diff --git a/demo/demo.sql b/demo/demo.sql
index 1a06d44..45c0a31 100644
--- a/demo/demo.sql
+++ b/demo/demo.sql
@@ -60,14 +60,15 @@ select add_product(1, 'Cavall Fort', 'Revista quinzenal en llengua catalana i de
 select add_product(1, 'Palla', 'Tija seca dels cereals després que el gra o llavor ha estat separat mitjançant la trilla.', '25.00', array[3]);
 select add_product(1, 'Teia', 'Fusta resinosa de pi i d’altres arbres, provinent sobretot del cor de l’arbre, que crema amb molta facilitat.', '7.00', array[2]);
 
+alter sequence tag_tag_id_seq restart;
 alter sequence invoice_invoice_id_seq restart;
 alter sequence invoice_product_invoice_product_id_seq restart;
-select add_invoice(1, '', (current_date - '28 days'::interval)::date, 6, 'Vol esmorzar!', 1, '{"(1,Teia,\"Fusta resinosa de pi i d’altres arbres, provinent sobretot del cor de l’arbre, que crema amb molta facilitat.\",7.00,1,0.0,{2})","(5,Cavall Fort,\"Revista quinzenal en llengua catalana i de còmic en català, destinada a infants i joves.\",3.64,1,0.0,{2})"}');
-select add_invoice(1, '', (current_date - '24 days'::interval)::date, 5, '', 1, '{"(1,Palla,Tija seca dels cereals després que el gra o llavor ha estat separat mitjançant la trilla.,25.00,25,0.0,{3})","(5,Cavall Fort,\"Revista quinzenal en llengua catalana i de còmic en català, destinada a infants i joves.\",3.64,1,0.0,{2})"}');
-select add_invoice(1, '', (current_date - '17 days'::interval)::date, 4, '', 1, '{"(1,\"Paper higiènic (pack de 32 U)\",Paper que s’usa per mantenir la higiene personal després de defecar o orinar.,7.99,10,0.0,{4})","(5,Cavall Fort,\"Revista quinzenal en llengua catalana i de còmic en català, destinada a infants i joves.\",3.64,1,0.0,{2})"}');
-select add_invoice(1, '', (current_date - '7 days'::interval)::date, 3, '', 1, '{"(1,Mirra,Goma resinosa aromàtica de color gris groguenc i gust amargant.,7.22,144,0.05,{2})","(5,Cavall Fort,\"Revista quinzenal en llengua catalana i de còmic en català, destinada a infants i joves.\",4.45,1,0.0,{2})"}');
-select add_invoice(1, '', (current_date - '4 days'::interval)::date, 2, '', 1, '{"(1,Encens,Goma resina fragrant que desprèn una olor característica quan es crema.,2.26,460,0.05,{2})","(5,Cavall Fort,\"Revista quinzenal en llengua catalana i de còmic en català, destinada a infants i joves.\",4.53,1,0.0,{2})"}');
-select add_invoice(1, '', (current_date - '1 days'::interval)::date, 1, '', 1, '{"(1,Or,\"Metall de transició tou, brillant, groc, pesant, mal·leable, dúctil i que no reacciona amb la majoria de productes químics, però és sensible al clor i a l’aigua règia.\",57.82,18,0.05,{2})","(5,Cavall Fort,\"Revista quinzenal en llengua catalana i de còmic en català, destinada a infants i joves.\",3.43,1,0.0,{2})"}');
+select add_invoice(1, '', (current_date - '28 days'::interval)::date, 6, 'Vol esmorzar!', 1, '{producte}','{"(1,Teia,\"Fusta resinosa de pi i d’altres arbres, provinent sobretot del cor de l’arbre, que crema amb molta facilitat.\",7.00,1,0.0,{2})","(5,Cavall Fort,\"Revista quinzenal en llengua catalana i de còmic en català, destinada a infants i joves.\",3.64,1,0.0,{2})"}');
+select add_invoice(1, '', (current_date - '24 days'::interval)::date, 5, '', 1, '{producte,bestia}','{"(1,Palla,Tija seca dels cereals després que el gra o llavor ha estat separat mitjançant la trilla.,25.00,25,0.0,{3})","(5,Cavall Fort,\"Revista quinzenal en llengua catalana i de còmic en català, destinada a infants i joves.\",3.64,1,0.0,{2})"}');
+select add_invoice(1, '', (current_date - '17 days'::interval)::date, 4, '', 1, '{producte,higiene}','{"(1,\"Paper higiènic (pack de 32 U)\",Paper que s’usa per mantenir la higiene personal després de defecar o orinar.,7.99,10,0.0,{4})","(5,Cavall Fort,\"Revista quinzenal en llengua catalana i de còmic en català, destinada a infants i joves.\",3.64,1,0.0,{2})"}');
+select add_invoice(1, '', (current_date - '7 days'::interval)::date, 3, '', 1, '{producte,mag}','{"(1,Mirra,Goma resinosa aromàtica de color gris groguenc i gust amargant.,7.22,144,0.05,{2})","(5,Cavall Fort,\"Revista quinzenal en llengua catalana i de còmic en català, destinada a infants i joves.\",4.45,1,0.0,{2})"}');
+select add_invoice(1, '', (current_date - '4 days'::interval)::date, 2, '', 1, '{producte,mag}','{"(1,Encens,Goma resina fragrant que desprèn una olor característica quan es crema.,2.26,460,0.05,{2})","(5,Cavall Fort,\"Revista quinzenal en llengua catalana i de còmic en català, destinada a infants i joves.\",4.53,1,0.0,{2})"}');
+select add_invoice(1, '', (current_date - '1 days'::interval)::date, 1, '', 1, '{producte,mag}','{"(1,Or,\"Metall de transició tou, brillant, groc, pesant, mal·leable, dúctil i que no reacciona amb la majoria de productes químics, però és sensible al clor i a l’aigua règia.\",57.82,18,0.05,{2})","(5,Cavall Fort,\"Revista quinzenal en llengua catalana i de còmic en català, destinada a infants i joves.\",3.43,1,0.0,{2})"}');
 
 update invoice set invoice_status = 'paid' where invoice_id in (1, 5);
 update invoice set invoice_status = 'unpaid' where invoice_id = 3;
diff --git a/deploy/add_invoice.sql b/deploy/add_invoice.sql
index e709ed5..0fff44c 100644
--- a/deploy/add_invoice.sql
+++ b/deploy/add_invoice.sql
@@ -9,12 +9,15 @@
 -- requires: invoice_product
 -- requires: invoice_product_tax
 -- requires: next_invoice_number
+-- requires: tag_name
+-- requires: tag
+-- requires: invoice_tag
 
 begin;
 
 set search_path to numerus, public;
 
-create or replace function add_invoice(company_id integer, invoice_number text, invoice_date date, contact_id integer, notes text, payment_method_id integer, products new_invoice_product[]) returns uuid as
+create or replace function add_invoice(company integer, invoice_number text, invoice_date date, contact_id integer, notes text, payment_method_id integer, tags tag_name[], products new_invoice_product[]) returns uuid as
 $$
 declare
 	iid integer;
@@ -24,11 +27,11 @@ declare
 	ipid integer;
 begin
 	if invoice_number is null or length(trim(invoice_number)) = 0 then
-		invoice_number = next_invoice_number(company_id, invoice_date);
+		invoice_number = next_invoice_number(company, invoice_date);
 	end if;
 
 	insert into invoice (company_id, invoice_number, invoice_date, contact_id, notes, currency_code, payment_method_id)
-	select company.company_id
+	select company_id
 	     , invoice_number
 	     , invoice_date
 	     , contact_id
@@ -36,7 +39,7 @@ begin
 	     , currency_code
 	     , add_invoice.payment_method_id
 	from company
-	where company.company_id = add_invoice.company_id
+	where company.company_id = add_invoice.company
 	returning invoice_id, slug, currency_code
 	into iid, pslug, ccode;
 
@@ -61,13 +64,27 @@ begin
 		join unnest(product.tax) as ptax(tax_id) using (tax_id);
 	end loop;
 
+	if array_length(tags, 1) > 0 then
+		insert into tag (company_id, name)
+		select add_invoice.company, new_tag.name
+		from unnest (tags) as new_tag(name)
+		on conflict (company_id, name) do nothing
+		;
+
+		insert into invoice_tag (invoice_id, tag_id)
+		select iid, tag_id
+		from tag
+		join unnest (tags) as new_tag(name) on company_id = add_invoice.company and tag.name = new_tag.name
+		;
+	end if;
+
 	return pslug;
 end;
 $$
 language plpgsql;
 
-revoke execute on function add_invoice(integer, text, date, integer, text, integer, new_invoice_product[]) from public;
-grant execute on function add_invoice(integer, text, date, integer, text, integer, new_invoice_product[]) to invoicer;
-grant execute on function add_invoice(integer, text, date, integer, text, integer, new_invoice_product[]) to admin;
+revoke execute on function add_invoice(integer, text, date, integer, text, integer, tag_name[], new_invoice_product[]) from public;
+grant execute on function add_invoice(integer, text, date, integer, text, integer, tag_name[], new_invoice_product[]) to invoicer;
+grant execute on function add_invoice(integer, text, date, integer, text, integer, tag_name[], new_invoice_product[]) to admin;
 
 commit;
diff --git a/deploy/invoice_tag.sql b/deploy/invoice_tag.sql
new file mode 100644
index 0000000..54f3ee2
--- /dev/null
+++ b/deploy/invoice_tag.sql
@@ -0,0 +1,31 @@
+-- Deploy numerus:invoice_tag to pg
+-- requires: schema_numerus
+-- requires: tag
+-- requires: invoice
+
+begin;
+
+set search_path to numerus, public;
+
+create table invoice_tag (
+	invoice_id integer not null references invoice,
+	tag_id integer not null references tag,
+	primary key (invoice_id, tag_id)
+);
+
+grant select, insert, update, delete on table invoice_tag to invoicer;
+grant select, insert, update, delete on table invoice_tag to admin;
+
+alter table invoice_tag enable row level security;
+
+create policy company_policy
+on invoice_tag
+using (
+	exists(
+		select 1
+		from invoice
+		where invoice.invoice_id = invoice_tag.invoice_id
+	)
+);
+
+commit;
diff --git a/deploy/tag.sql b/deploy/tag.sql
new file mode 100644
index 0000000..3071316
--- /dev/null
+++ b/deploy/tag.sql
@@ -0,0 +1,35 @@
+-- Deploy numerus:tag to pg
+-- requires: schema_numerus
+-- requires: tag_name
+
+begin;
+
+set search_path to numerus, public;
+
+create table tag (
+	tag_id serial primary key,
+	company_id integer not null references company,
+	name tag_name not null,
+	unique (company_id, name)
+);
+
+grant select, insert, update, delete on table tag to invoicer;
+grant select, insert, update, delete on table tag to admin;
+
+grant usage on sequence tag_tag_id_seq to invoicer;
+grant usage on sequence tag_tag_id_seq to admin;
+
+alter table tag enable row level security;
+
+create policy company_policy
+on tag
+using (
+	exists(
+		select 1
+		from company_user
+		join user_profile using (user_id)
+		where company_user.company_id = tag.company_id
+	)
+);
+
+commit;
diff --git a/deploy/tag_name.sql b/deploy/tag_name.sql
new file mode 100644
index 0000000..70f6d5a
--- /dev/null
+++ b/deploy/tag_name.sql
@@ -0,0 +1,12 @@
+-- Deploy numerus:tag_name to pg
+-- requires: schema_numerus
+
+begin;
+
+set search_path to numerus, public;
+
+-- The same as a topic on gitea
+create domain tag_name as text
+check ( value ~ '^[a-z0-9][a-z0-9-]{0,34}$' );
+
+commit;
diff --git a/pkg/invoices.go b/pkg/invoices.go
index fe39bf5..a1e9c6f 100644
--- a/pkg/invoices.go
+++ b/pkg/invoices.go
@@ -14,6 +14,7 @@ import (
 	"net/http"
 	"os"
 	"os/exec"
+	"regexp"
 	"sort"
 	"strconv"
 	"strings"
@@ -27,6 +28,7 @@ type InvoiceEntry struct {
 	Total        string
 	CustomerName string
 	CustomerSlug string
+	Tags         []string
 	Status       string
 	StatusLabel  string
 }
@@ -39,21 +41,51 @@ type InvoicesIndexPage struct {
 func IndexInvoices(w http.ResponseWriter, r *http.Request, _ httprouter.Params) {
 	conn := getConn(r)
 	locale := getLocale(r)
+	tag := r.URL.Query().Get("tag")
 	page := &InvoicesIndexPage{
-		Invoices:        mustCollectInvoiceEntries(r.Context(), conn, mustGetCompany(r), locale),
+		Invoices:        mustCollectInvoiceEntries(r.Context(), conn, mustGetCompany(r), locale, tag),
 		InvoiceStatuses: mustCollectInvoiceStatuses(r.Context(), conn, locale),
 	}
 	mustRenderAppTemplate(w, r, "invoices/index.gohtml", page)
 }
 
-func mustCollectInvoiceEntries(ctx context.Context, conn *Conn, company *Company, locale *Locale) []*InvoiceEntry {
-	rows := conn.MustQuery(ctx, "select invoice.slug, invoice_date, invoice_number, contact.business_name, contact.slug, invoice.invoice_status, isi18n.name, to_price(total, decimal_digits) from invoice join contact using (contact_id) join invoice_status_i18n isi18n on invoice.invoice_status = isi18n.invoice_status and isi18n.lang_tag = $2 join invoice_amount using (invoice_id) join currency using (currency_code) where invoice.company_id = $1 order by invoice_date desc, invoice_number desc", company.Id, locale.Language.String())
+func mustCollectInvoiceEntries(ctx context.Context, conn *Conn, company *Company, locale *Locale, tag string) []*InvoiceEntry {
+	rows := conn.MustQuery(ctx, `
+		select invoice.slug
+		     , invoice_date
+		     , invoice_number
+		     , contact.business_name
+		     , contact.slug
+		     , array_agg(tag.name::text)
+		     , invoice.invoice_status
+		     , isi18n.name
+		     , to_price(total, decimal_digits)
+		from invoice
+		left join invoice_tag using (invoice_id)
+		left join tag using(tag_id)
+		join contact using (contact_id)
+		join invoice_status_i18n isi18n on invoice.invoice_status = isi18n.invoice_status and isi18n.lang_tag = $2
+		join invoice_amount using (invoice_id)
+		join currency using (currency_code)
+		where invoice.company_id = $1 and (($3 = '') or (tag.name = $3))
+		group by invoice.slug
+		       , invoice_date
+		       , invoice_number
+		       , contact.business_name
+		       , contact.slug
+		       , invoice.invoice_status
+		       , isi18n.name
+		       , total
+		       , decimal_digits
+		order by invoice_date desc
+		       , invoice_number desc
+	`, company.Id, locale.Language.String(), tag)
 	defer rows.Close()
 
 	var entries []*InvoiceEntry
 	for rows.Next() {
 		entry := &InvoiceEntry{}
-		if err := rows.Scan(&entry.Slug, &entry.Date, &entry.Number, &entry.CustomerName, &entry.CustomerSlug, &entry.Status, &entry.StatusLabel, &entry.Total); err != nil {
+		if err := rows.Scan(&entry.Slug, &entry.Date, &entry.Number, &entry.CustomerName, &entry.CustomerSlug, &entry.Tags, &entry.Status, &entry.StatusLabel, &entry.Total); err != nil {
 			panic(err)
 		}
 		entries = append(entries, entry)
@@ -330,7 +362,9 @@ func HandleAddInvoice(w http.ResponseWriter, r *http.Request, _ httprouter.Param
 		mustRenderNewInvoiceForm(w, r, form)
 		return
 	}
-	slug := conn.MustGetText(r.Context(), "", "select add_invoice($1, $2, $3, $4, $5, $6, $7)", company.Id, form.Number, form.Date, form.Customer, form.Notes, form.PaymentMethod, NewInvoiceProductArray(form.Products))
+	reg := regexp.MustCompile("[^a-z0-9-]+")
+	tags := strings.Split(reg.ReplaceAllString(form.Tags.Val, " "), " ")
+	slug := conn.MustGetText(r.Context(), "", "select add_invoice($1, $2, $3, $4, $5, $6, $7, $8)", company.Id, form.Number, form.Date, form.Customer, form.Notes, form.PaymentMethod, tags, NewInvoiceProductArray(form.Products))
 	http.Redirect(w, r, companyURI(company, "/invoices/"+slug), http.StatusSeeOther)
 }
 
@@ -421,6 +455,7 @@ type invoiceForm struct {
 	Date          *InputField
 	Notes         *InputField
 	PaymentMethod *SelectField
+	Tags          *InputField
 	Products      []*invoiceProductForm
 }
 
@@ -435,10 +470,9 @@ func newInvoiceForm(ctx context.Context, conn *Conn, locale *Locale, company *Co
 			Options:  MustGetOptions(ctx, conn, "select contact_id::text, business_name from contact where company_id = $1 order by business_name", company.Id),
 		},
 		Number: &InputField{
-			Name:     "number",
-			Label:    pgettext("input", "Number", locale),
-			Type:     "text",
-			Required: false,
+			Name:  "number",
+			Label: pgettext("input", "Number", locale),
+			Type:  "text",
 		},
 		Date: &InputField{
 			Name:     "date",
@@ -451,6 +485,11 @@ func newInvoiceForm(ctx context.Context, conn *Conn, locale *Locale, company *Co
 			Label: pgettext("input", "Notes", locale),
 			Type:  "textarea",
 		},
+		Tags: &InputField{
+			Name:  "tags",
+			Label: pgettext("input", "Tags", locale),
+			Type:  "text",
+		},
 		PaymentMethod: &SelectField{
 			Name:     "payment_method",
 			Required: true,
@@ -469,6 +508,7 @@ func (form *invoiceForm) Parse(r *http.Request) error {
 	form.Number.FillValue(r)
 	form.Date.FillValue(r)
 	form.Notes.FillValue(r)
+	form.Tags.FillValue(r)
 	form.PaymentMethod.FillValue(r)
 	if _, ok := r.Form["product.id.0"]; ok {
 		taxOptions := mustGetTaxOptions(r.Context(), getConn(r), form.company)
@@ -541,7 +581,24 @@ func (form *invoiceForm) MustFillFromDatabase(ctx context.Context, conn *Conn, s
 	var invoiceId int
 	selectedPaymentMethod := form.PaymentMethod.Selected
 	form.PaymentMethod.Clear()
-	if notFoundErrorOrPanic(conn.QueryRow(ctx, "select invoice_id, contact_id, invoice_number, invoice_date, notes, payment_method_id from invoice where slug = $1", slug).Scan(&invoiceId, form.Customer, form.Number, form.Date, form.Notes, form.PaymentMethod)) {
+	if notFoundErrorOrPanic(conn.QueryRow(ctx, `
+		select invoice_id
+		     , contact_id
+		     , invoice_number
+		     , invoice_date
+		     , notes
+		     , payment_method_id
+		     , string_agg(tag.name, ', ')
+		from invoice
+		left join invoice_tag using (invoice_id)
+		left join tag using(tag_id) where slug = $1
+		group by invoice_id
+		       , contact_id
+		       , invoice_number
+		       , invoice_date
+		       , notes
+		       , payment_method_id
+	`, slug).Scan(&invoiceId, form.Customer, form.Number, form.Date, form.Notes, form.PaymentMethod, form.Tags)) {
 		form.PaymentMethod.Selected = selectedPaymentMethod
 		return
 	}
diff --git a/po/ca.po b/po/ca.po
index c7cc2ae..70057f6 100644
--- a/po/ca.po
+++ b/po/ca.po
@@ -8,7 +8,7 @@ msgid ""
 msgstr ""
 "Project-Id-Version: numerus\n"
 "Report-Msgid-Bugs-To: jordi@tandem.blog\n"
-"POT-Creation-Date: 2023-03-09 12:08+0100\n"
+"POT-Creation-Date: 2023-03-10 13:59+0100\n"
 "PO-Revision-Date: 2023-01-18 17:08+0100\n"
 "Last-Translator: jordi fita mas <jordi@tandem.blog>\n"
 "Language-Team: Catalan <ca@dodds.net>\n"
@@ -46,51 +46,51 @@ msgctxt "title"
 msgid "New Invoice"
 msgstr "Nova factura"
 
-#: web/template/invoices/products.gohtml:41
+#: web/template/invoices/products.gohtml:42
 #: web/template/products/index.gohtml:21
 msgctxt "product"
 msgid "All"
 msgstr "Tots"
 
-#: web/template/invoices/products.gohtml:42
+#: web/template/invoices/products.gohtml:43
 #: web/template/products/index.gohtml:22
 msgctxt "title"
 msgid "Name"
 msgstr "Nom"
 
-#: web/template/invoices/products.gohtml:43
+#: web/template/invoices/products.gohtml:44
 #: web/template/invoices/view.gohtml:54 web/template/products/index.gohtml:23
 msgctxt "title"
 msgid "Price"
 msgstr "Preu"
 
-#: web/template/invoices/products.gohtml:57
+#: web/template/invoices/products.gohtml:58
 #: web/template/products/index.gohtml:37
 msgid "No products added yet."
 msgstr "No hi ha cap producte."
 
-#: web/template/invoices/products.gohtml:65 web/template/invoices/new.gohtml:61
+#: web/template/invoices/products.gohtml:66 web/template/invoices/new.gohtml:62
 msgctxt "action"
 msgid "Add products"
 msgstr "Afegeix productes"
 
-#: web/template/invoices/new.gohtml:42 web/template/invoices/view.gohtml:59
+#: web/template/invoices/new.gohtml:43 web/template/invoices/view.gohtml:59
 msgctxt "title"
 msgid "Subtotal"
 msgstr "Subtotal"
 
-#: web/template/invoices/new.gohtml:52 web/template/invoices/view.gohtml:63
+#: web/template/invoices/new.gohtml:53 web/template/invoices/view.gohtml:63
 #: web/template/invoices/view.gohtml:103
 msgctxt "title"
 msgid "Total"
 msgstr "Total"
 
-#: web/template/invoices/new.gohtml:64
+#: web/template/invoices/new.gohtml:65
 msgctxt "action"
 msgid "Update"
 msgstr "Actualitza"
 
-#: web/template/invoices/new.gohtml:66 web/template/invoices/index.gohtml:19
+#: web/template/invoices/new.gohtml:67 web/template/invoices/index.gohtml:19
 msgctxt "action"
 msgid "New invoice"
 msgstr "Nova factura"
@@ -127,8 +127,8 @@ msgstr "Estat"
 
 #: web/template/invoices/index.gohtml:33
 msgctxt "title"
-msgid "Label"
-msgstr "Etiqueta"
+msgid "Tags"
+msgstr "Etiquetes"
 
 #: web/template/invoices/index.gohtml:34
 msgctxt "title"
@@ -150,12 +150,12 @@ msgctxt "action"
 msgid "Select invoice %v"
 msgstr "Selecciona factura %v"
 
-#: web/template/invoices/index.gohtml:86 web/template/invoices/view.gohtml:14
+#: web/template/invoices/index.gohtml:91 web/template/invoices/view.gohtml:14
 msgctxt "action"
 msgid "Duplicate"
 msgstr "Duplica"
 
-#: web/template/invoices/index.gohtml:96
+#: web/template/invoices/index.gohtml:101
 msgid "No invoices added yet."
 msgstr "No hi ha cap factura."
 
@@ -428,44 +428,44 @@ msgstr "No podeu deixar la contrasenya en blanc."
 msgid "Invalid user or password."
 msgstr "Nom d’usuari o contrasenya incorrectes."
 
-#: pkg/products.go:165 pkg/invoices.go:578
+#: pkg/products.go:165 pkg/invoices.go:635
 msgctxt "input"
 msgid "Name"
 msgstr "Nom"
 
-#: pkg/products.go:171 pkg/invoices.go:583
+#: pkg/products.go:171 pkg/invoices.go:640
 msgctxt "input"
 msgid "Description"
 msgstr "Descripció"
 
-#: pkg/products.go:176 pkg/invoices.go:587
+#: pkg/products.go:176 pkg/invoices.go:644
 msgctxt "input"
 msgid "Price"
 msgstr "Preu"
 
-#: pkg/products.go:186 pkg/invoices.go:613
+#: pkg/products.go:186 pkg/invoices.go:670
 msgctxt "input"
 msgid "Taxes"
 msgstr "Imposts"
 
-#: pkg/products.go:206 pkg/profile.go:92 pkg/invoices.go:492
-#: pkg/invoices.go:649
+#: pkg/products.go:206 pkg/profile.go:92 pkg/invoices.go:532
+#: pkg/invoices.go:706
 msgid "Name can not be empty."
 msgstr "No podeu deixar el nom en blanc."
 
-#: pkg/products.go:207 pkg/invoices.go:650
+#: pkg/products.go:207 pkg/invoices.go:707
 msgid "Price can not be empty."
 msgstr "No podeu deixar el preu en blanc."
 
-#: pkg/products.go:208 pkg/invoices.go:651
+#: pkg/products.go:208 pkg/invoices.go:708
 msgid "Price must be a number greater than zero."
 msgstr "El preu ha de ser un número major a zero."
 
-#: pkg/products.go:210 pkg/invoices.go:659
+#: pkg/products.go:210 pkg/invoices.go:716
 msgid "Selected tax is not valid."
 msgstr "Heu seleccionat un impost que no és vàlid."
 
-#: pkg/products.go:211 pkg/invoices.go:660
+#: pkg/products.go:211 pkg/invoices.go:717
 msgid "You can only select a tax of each class."
 msgstr "Només podeu seleccionar un impost de cada classe."
 
@@ -573,83 +573,88 @@ msgstr "La confirmació no és igual a la contrasenya."
 msgid "Selected language is not valid."
 msgstr "Heu seleccionat un idioma que no és vàlid."
 
-#: pkg/invoices.go:270
+#: pkg/invoices.go:302
 msgid "Select a customer to bill."
 msgstr "Escolliu un client a facturar."
 
-#: pkg/invoices.go:363 pkg/invoices.go:392
+#: pkg/invoices.go:397 pkg/invoices.go:426
 msgid "Invalid action"
 msgstr "Acció invàlida."
 
-#: pkg/invoices.go:386
+#: pkg/invoices.go:420
 msgid "invoices.zip"
 msgstr "factures.zip"
 
-#: pkg/invoices.go:433
+#: pkg/invoices.go:468
 msgctxt "input"
 msgid "Customer"
 msgstr "Client"
 
-#: pkg/invoices.go:439
+#: pkg/invoices.go:474
 msgctxt "input"
 msgid "Number"
 msgstr "Número"
 
-#: pkg/invoices.go:445
+#: pkg/invoices.go:479
 msgctxt "input"
 msgid "Invoice Date"
 msgstr "Data de factura"
 
-#: pkg/invoices.go:451
+#: pkg/invoices.go:485
 msgctxt "input"
 msgid "Notes"
 msgstr "Notes"
 
-#: pkg/invoices.go:457
+#: pkg/invoices.go:490
+msgctxt "input"
+msgid "Tags"
+msgstr "Etiquetes"
+
+#: pkg/invoices.go:496
 msgctxt "input"
 msgid "Payment Method"
 msgstr "Mètode de pagament"
 
-#: pkg/invoices.go:493
+#: pkg/invoices.go:533
 msgid "Invoice date can not be empty."
 msgstr "No podeu deixar la data de la factura en blanc."
 
-#: pkg/invoices.go:494
+#: pkg/invoices.go:534
 msgid "Invoice date must be a valid date."
 msgstr "La data de facturació ha de ser vàlida."
 
-#: pkg/invoices.go:496
+#: pkg/invoices.go:536
 msgid "Selected payment method is not valid."
 msgstr "Heu seleccionat un mètode de pagament que no és vàlid."
 
-#: pkg/invoices.go:573
+#: pkg/invoices.go:630
 msgctxt "input"
 msgid "Id"
 msgstr "Identificador"
 
-#: pkg/invoices.go:596
+#: pkg/invoices.go:653
 msgctxt "input"
 msgid "Quantity"
 msgstr "Quantitat"
 
-#: pkg/invoices.go:604
+#: pkg/invoices.go:661
 msgctxt "input"
 msgid "Discount (%)"
 msgstr "Descompte (%)"
 
-#: pkg/invoices.go:653
+#: pkg/invoices.go:710
 msgid "Quantity can not be empty."
 msgstr "No podeu deixar la quantitat en blanc."
 
-#: pkg/invoices.go:654
+#: pkg/invoices.go:711
 msgid "Quantity must be a number greater than zero."
 msgstr "La quantitat ha de ser un número major a zero."
 
-#: pkg/invoices.go:656
+#: pkg/invoices.go:713
 msgid "Discount can not be empty."
 msgstr "No podeu deixar el descompte en blanc."
 
-#: pkg/invoices.go:657
+#: pkg/invoices.go:714
 msgid "Discount must be a percentage between 0 and 100."
 msgstr "El descompte ha de ser un percentatge entre 0 i 100."
 
@@ -751,6 +756,10 @@ msgstr "No podeu deixar el codi postal en blanc."
 msgid "This value is not a valid postal code."
 msgstr "Aquest valor no és un codi postal vàlid."
 
+#~ msgctxt "title"
+#~ msgid "Label"
+#~ msgstr "Etiqueta"
+
 #~ msgid "Select a tax for this product."
 #~ msgstr "Escolliu un impost per aquest producte."
 
diff --git a/po/es.po b/po/es.po
index 54e38f4..4a8374d 100644
--- a/po/es.po
+++ b/po/es.po
@@ -7,7 +7,7 @@ msgid ""
 msgstr ""
 "Project-Id-Version: numerus\n"
 "Report-Msgid-Bugs-To: jordi@tandem.blog\n"
-"POT-Creation-Date: 2023-03-09 12:08+0100\n"
+"POT-Creation-Date: 2023-03-10 13:59+0100\n"
 "PO-Revision-Date: 2023-01-18 17:45+0100\n"
 "Last-Translator: jordi fita mas <jordi@tandem.blog>\n"
 "Language-Team: Spanish <es@tp.org.es>\n"
@@ -46,51 +46,51 @@ msgctxt "title"
 msgid "New Invoice"
 msgstr "Nueva factura"
 
-#: web/template/invoices/products.gohtml:41
+#: web/template/invoices/products.gohtml:42
 #: web/template/products/index.gohtml:21
 msgctxt "product"
 msgid "All"
 msgstr "Todos"
 
-#: web/template/invoices/products.gohtml:42
+#: web/template/invoices/products.gohtml:43
 #: web/template/products/index.gohtml:22
 msgctxt "title"
 msgid "Name"
 msgstr "Nombre"
 
-#: web/template/invoices/products.gohtml:43
+#: web/template/invoices/products.gohtml:44
 #: web/template/invoices/view.gohtml:54 web/template/products/index.gohtml:23
 msgctxt "title"
 msgid "Price"
 msgstr "Precio"
 
-#: web/template/invoices/products.gohtml:57
+#: web/template/invoices/products.gohtml:58
 #: web/template/products/index.gohtml:37
 msgid "No products added yet."
 msgstr "No hay productos."
 
-#: web/template/invoices/products.gohtml:65 web/template/invoices/new.gohtml:61
+#: web/template/invoices/products.gohtml:66 web/template/invoices/new.gohtml:62
 msgctxt "action"
 msgid "Add products"
 msgstr "Añadir productos"
 
-#: web/template/invoices/new.gohtml:42 web/template/invoices/view.gohtml:59
+#: web/template/invoices/new.gohtml:43 web/template/invoices/view.gohtml:59
 msgctxt "title"
 msgid "Subtotal"
 msgstr "Subtotal"
 
-#: web/template/invoices/new.gohtml:52 web/template/invoices/view.gohtml:63
+#: web/template/invoices/new.gohtml:53 web/template/invoices/view.gohtml:63
 #: web/template/invoices/view.gohtml:103
 msgctxt "title"
 msgid "Total"
 msgstr "Total"
 
-#: web/template/invoices/new.gohtml:64
+#: web/template/invoices/new.gohtml:65
 msgctxt "action"
 msgid "Update"
 msgstr "Actualizar"
 
-#: web/template/invoices/new.gohtml:66 web/template/invoices/index.gohtml:19
+#: web/template/invoices/new.gohtml:67 web/template/invoices/index.gohtml:19
 msgctxt "action"
 msgid "New invoice"
 msgstr "Nueva factura"
@@ -127,8 +127,8 @@ msgstr "Estado"
 
 #: web/template/invoices/index.gohtml:33
 msgctxt "title"
-msgid "Label"
-msgstr "Etiqueta"
+msgid "Tags"
+msgstr "Etiquetes"
 
 #: web/template/invoices/index.gohtml:34
 msgctxt "title"
@@ -150,12 +150,12 @@ msgctxt "action"
 msgid "Select invoice %v"
 msgstr "Seleccionar factura %v"
 
-#: web/template/invoices/index.gohtml:86 web/template/invoices/view.gohtml:14
+#: web/template/invoices/index.gohtml:91 web/template/invoices/view.gohtml:14
 msgctxt "action"
 msgid "Duplicate"
 msgstr "Duplicar"
 
-#: web/template/invoices/index.gohtml:96
+#: web/template/invoices/index.gohtml:101
 msgid "No invoices added yet."
 msgstr "No hay facturas."
 
@@ -428,44 +428,44 @@ msgstr "No podéis dejar la contraseña en blanco."
 msgid "Invalid user or password."
 msgstr "Nombre de usuario o contraseña inválido."
 
-#: pkg/products.go:165 pkg/invoices.go:578
+#: pkg/products.go:165 pkg/invoices.go:635
 msgctxt "input"
 msgid "Name"
 msgstr "Nombre"
 
-#: pkg/products.go:171 pkg/invoices.go:583
+#: pkg/products.go:171 pkg/invoices.go:640
 msgctxt "input"
 msgid "Description"
 msgstr "Descripción"
 
-#: pkg/products.go:176 pkg/invoices.go:587
+#: pkg/products.go:176 pkg/invoices.go:644
 msgctxt "input"
 msgid "Price"
 msgstr "Precio"
 
-#: pkg/products.go:186 pkg/invoices.go:613
+#: pkg/products.go:186 pkg/invoices.go:670
 msgctxt "input"
 msgid "Taxes"
 msgstr "Impuestos"
 
-#: pkg/products.go:206 pkg/profile.go:92 pkg/invoices.go:492
-#: pkg/invoices.go:649
+#: pkg/products.go:206 pkg/profile.go:92 pkg/invoices.go:532
+#: pkg/invoices.go:706
 msgid "Name can not be empty."
 msgstr "No podéis dejar el nombre en blanco."
 
-#: pkg/products.go:207 pkg/invoices.go:650
+#: pkg/products.go:207 pkg/invoices.go:707
 msgid "Price can not be empty."
 msgstr "No podéis dejar el precio en blanco."
 
-#: pkg/products.go:208 pkg/invoices.go:651
+#: pkg/products.go:208 pkg/invoices.go:708
 msgid "Price must be a number greater than zero."
 msgstr "El precio tiene que ser un número mayor a cero."
 
-#: pkg/products.go:210 pkg/invoices.go:659
+#: pkg/products.go:210 pkg/invoices.go:716
 msgid "Selected tax is not valid."
 msgstr "Habéis escogido un impuesto que no es válido."
 
-#: pkg/products.go:211 pkg/invoices.go:660
+#: pkg/products.go:211 pkg/invoices.go:717
 msgid "You can only select a tax of each class."
 msgstr "Solo podéis escoger un impuesto de cada clase."
 
@@ -573,83 +573,88 @@ msgstr "La confirmación no corresponde con la contraseña."
 msgid "Selected language is not valid."
 msgstr "Habéis escogido un idioma que no es válido."
 
-#: pkg/invoices.go:270
+#: pkg/invoices.go:302
 msgid "Select a customer to bill."
 msgstr "Escoged un cliente a facturar."
 
-#: pkg/invoices.go:363 pkg/invoices.go:392
+#: pkg/invoices.go:397 pkg/invoices.go:426
 msgid "Invalid action"
 msgstr "Acción inválida."
 
-#: pkg/invoices.go:386
+#: pkg/invoices.go:420
 msgid "invoices.zip"
 msgstr "facturas.zip"
 
-#: pkg/invoices.go:433
+#: pkg/invoices.go:468
 msgctxt "input"
 msgid "Customer"
 msgstr "Cliente"
 
-#: pkg/invoices.go:439
+#: pkg/invoices.go:474
 msgctxt "input"
 msgid "Number"
 msgstr "Número"
 
-#: pkg/invoices.go:445
+#: pkg/invoices.go:479
 msgctxt "input"
 msgid "Invoice Date"
 msgstr "Fecha de factura"
 
-#: pkg/invoices.go:451
+#: pkg/invoices.go:485
 msgctxt "input"
 msgid "Notes"
 msgstr "Notas"
 
-#: pkg/invoices.go:457
+#: pkg/invoices.go:490
+msgctxt "input"
+msgid "Tags"
+msgstr "Etiquetes"
+
+#: pkg/invoices.go:496
 msgctxt "input"
 msgid "Payment Method"
 msgstr "Método de pago"
 
-#: pkg/invoices.go:493
+#: pkg/invoices.go:533
 msgid "Invoice date can not be empty."
 msgstr "No podéis dejar la fecha de la factura en blanco."
 
-#: pkg/invoices.go:494
+#: pkg/invoices.go:534
 msgid "Invoice date must be a valid date."
 msgstr "La fecha de factura debe ser válida."
 
-#: pkg/invoices.go:496
+#: pkg/invoices.go:536
 msgid "Selected payment method is not valid."
 msgstr "Habéis escogido un método de pago que no es válido."
 
-#: pkg/invoices.go:573
+#: pkg/invoices.go:630
 msgctxt "input"
 msgid "Id"
 msgstr "Identificador"
 
-#: pkg/invoices.go:596
+#: pkg/invoices.go:653
 msgctxt "input"
 msgid "Quantity"
 msgstr "Cantidad"
 
-#: pkg/invoices.go:604
+#: pkg/invoices.go:661
 msgctxt "input"
 msgid "Discount (%)"
 msgstr "Descuento (%)"
 
-#: pkg/invoices.go:653
+#: pkg/invoices.go:710
 msgid "Quantity can not be empty."
 msgstr "No podéis dejar la cantidad en blanco."
 
-#: pkg/invoices.go:654
+#: pkg/invoices.go:711
 msgid "Quantity must be a number greater than zero."
 msgstr "La cantidad tiene que ser un número mayor a cero."
 
-#: pkg/invoices.go:656
+#: pkg/invoices.go:713
 msgid "Discount can not be empty."
 msgstr "No podéis dejar el descuento en blanco."
 
-#: pkg/invoices.go:657
+#: pkg/invoices.go:714
 msgid "Discount must be a percentage between 0 and 100."
 msgstr "El descuento tiene que ser un porcentaje entre 0 y 100."
 
@@ -751,6 +756,10 @@ msgstr "No podéis dejar el código postal en blanco."
 msgid "This value is not a valid postal code."
 msgstr "Este valor no es un código postal válido válido."
 
+#~ msgctxt "title"
+#~ msgid "Label"
+#~ msgstr "Etiqueta"
+
 #~ msgid "Select a tax for this product."
 #~ msgstr "Escoged un impuesto para este producto."
 
diff --git a/revert/add_invoice.sql b/revert/add_invoice.sql
index 612cc0d..7a200d9 100644
--- a/revert/add_invoice.sql
+++ b/revert/add_invoice.sql
@@ -2,6 +2,6 @@
 
 begin;
 
-drop function if exists numerus.add_invoice(integer, text, date, integer, text, integer, numerus.new_invoice_product[]);
+drop function if exists numerus.add_invoice(integer, text, date, integer, text, integer, numerus.tag_name[], numerus.new_invoice_product[]);
 
 commit;
diff --git a/revert/invoice_tag.sql b/revert/invoice_tag.sql
new file mode 100644
index 0000000..49192e7
--- /dev/null
+++ b/revert/invoice_tag.sql
@@ -0,0 +1,7 @@
+-- Revert numerus:invoice_tag from pg
+
+begin;
+
+drop table if exists numerus.invoice_tag;
+
+commit;
diff --git a/revert/tag.sql b/revert/tag.sql
new file mode 100644
index 0000000..f936d9a
--- /dev/null
+++ b/revert/tag.sql
@@ -0,0 +1,7 @@
+-- Revert numerus:tag from pg
+
+begin;
+
+drop table if exists numerus.tag;
+
+commit;
diff --git a/revert/tag_name.sql b/revert/tag_name.sql
new file mode 100644
index 0000000..69a026d
--- /dev/null
+++ b/revert/tag_name.sql
@@ -0,0 +1,7 @@
+-- Revert numerus:tag_name from pg
+
+begin;
+
+drop domain if exists numerus.tag_name;
+
+commit;
diff --git a/sqitch.plan b/sqitch.plan
index 629b635..bfa237f 100644
--- a/sqitch.plan
+++ b/sqitch.plan
@@ -58,7 +58,10 @@ invoice_product_tax [schema_numerus invoice_product tax tax_rate] 2023-02-15T13:
 new_invoice_product [schema_numerus] 2023-02-16T21:06:01Z jordi fita mas <jordi@tandem.blog> # Add type for passing products to new invoices
 invoice_number_counter [schema_numerus company] 2023-02-17T13:04:48Z jordi fita mas <jordi@tandem.blog> # Add relation to count invoice numbers
 next_invoice_number [schema_numerus invoice_number_counter] 2023-02-17T13:21:48Z jordi fita mas <jordi@tandem.blog> # Add function to retrieve the next invoice number
-add_invoice [schema_numerus invoice company currency parse_price new_invoice_product tax invoice_product invoice_product_tax next_invoice_number] 2023-02-16T21:12:46Z jordi fita mas <jordi@tandem.blog> # Add function to create new invoices
+tag_name [schema_numerus] 2023-03-10T11:06:11Z jordi fita mas <jordi@tandem.blog> # Add domain for tag names
+tag [schema_numerus tag_name] 2023-03-10T11:04:24Z jordi fita mas <jordi@tandem.blog> # Add relation for tags
+invoice_tag [schema_numerus tag invoice] 2023-03-10T11:37:43Z jordi fita mas <jordi@tandem.blog> # Add relation for invoice tag
+add_invoice [schema_numerus invoice company currency parse_price new_invoice_product tax invoice_product invoice_product_tax next_invoice_number tag_name tag invoice_tag] 2023-02-16T21:12:46Z jordi fita mas <jordi@tandem.blog> # Add function to create new invoices
 invoice_tax_amount [schema_numerus invoice_product invoice_product_tax] 2023-02-22T12:08:35Z jordi fita mas <jordi@tandem.blog> # Add view for invoice tax amount
 invoice_product_amount [schema_numerus invoice_product invoice_product_tax] 2023-03-01T11:18:05Z jordi fita mas <jordi@tandem.blog> # Add view for invoice product subtotal and total
 invoice_amount [schema_numerus invoice_product invoice_product_amount] 2023-02-22T12:58:46Z jordi fita mas <jordi@tandem.blog> # Add view to compute subtotal and total for invoices
diff --git a/test/add_invoice.sql b/test/add_invoice.sql
index e95ccd6..df31966 100644
--- a/test/add_invoice.sql
+++ b/test/add_invoice.sql
@@ -5,22 +5,24 @@ reset client_min_messages;
 
 begin;
 
-select plan(17);
+select plan(19);
 
 set search_path to auth, numerus, public;
 
-select has_function('numerus', 'add_invoice', array ['integer', 'text', 'date', 'integer', 'text', 'integer', 'new_invoice_product[]']);
-select function_lang_is('numerus', 'add_invoice', array ['integer', 'text', 'date', 'integer', 'text', 'integer', 'new_invoice_product[]'], 'plpgsql');
-select function_returns('numerus', 'add_invoice', array ['integer', 'text', 'date', 'integer', 'text', 'integer', 'new_invoice_product[]'], 'uuid');
-select isnt_definer('numerus', 'add_invoice', array ['integer', 'text', 'date', 'integer', 'text', 'integer', 'new_invoice_product[]']);
-select volatility_is('numerus', 'add_invoice', array ['integer', 'text', 'date', 'integer', 'text', 'integer', 'new_invoice_product[]'], 'volatile');
-select function_privs_are('numerus', 'add_invoice', array ['integer', 'text', 'date', 'integer', 'text', 'integer', 'new_invoice_product[]'], 'guest', array []::text[]);
-select function_privs_are('numerus', 'add_invoice', array ['integer', 'text', 'date', 'integer', 'text', 'integer', 'new_invoice_product[]'], 'invoicer', array ['EXECUTE']);
-select function_privs_are('numerus', 'add_invoice', array ['integer', 'text', 'date', 'integer', 'text', 'integer', 'new_invoice_product[]'], 'admin', array ['EXECUTE']);
-select function_privs_are('numerus', 'add_invoice', array ['integer', 'text', 'date', 'integer', 'text', 'integer', 'new_invoice_product[]'], 'authenticator', array []::text[]);
+select has_function('numerus', 'add_invoice', array ['integer', 'text', 'date', 'integer', 'text', 'integer', 'tag_name[]', 'new_invoice_product[]']);
+select function_lang_is('numerus', 'add_invoice', array ['integer', 'text', 'date', 'integer', 'text', 'integer', 'tag_name[]', 'new_invoice_product[]'], 'plpgsql');
+select function_returns('numerus', 'add_invoice', array ['integer', 'text', 'date', 'integer', 'text', 'integer', 'tag_name[]', 'new_invoice_product[]'], 'uuid');
+select isnt_definer('numerus', 'add_invoice', array ['integer', 'text', 'date', 'integer', 'text', 'integer', 'tag_name[]', 'new_invoice_product[]']);
+select volatility_is('numerus', 'add_invoice', array ['integer', 'text', 'date', 'integer', 'text', 'integer', 'tag_name[]', 'new_invoice_product[]'], 'volatile');
+select function_privs_are('numerus', 'add_invoice', array ['integer', 'text', 'date', 'integer', 'text', 'integer', 'tag_name[]', 'new_invoice_product[]'], 'guest', array []::text[]);
+select function_privs_are('numerus', 'add_invoice', array ['integer', 'text', 'date', 'integer', 'text', 'integer', 'tag_name[]', 'new_invoice_product[]'], 'invoicer', array ['EXECUTE']);
+select function_privs_are('numerus', 'add_invoice', array ['integer', 'text', 'date', 'integer', 'text', 'integer', 'tag_name[]', 'new_invoice_product[]'], 'admin', array ['EXECUTE']);
+select function_privs_are('numerus', 'add_invoice', array ['integer', 'text', 'date', 'integer', 'text', 'integer', 'tag_name[]', 'new_invoice_product[]'], 'authenticator', array []::text[]);
 
 
 set client_min_messages to warning;
+truncate invoice_tag cascade;
+truncate tag cascade;
 truncate invoice_number_counter cascade;
 truncate invoice_product_tax cascade;
 truncate invoice_product cascade;
@@ -81,27 +83,27 @@ values (12, 1, 'Contact 2.1', 'XX555', '', '777-777-777', 'c@c', '', '', '', '',
 
 
 select lives_ok(
-	$$ select add_invoice(1, 'INV001', '2023-02-15', 12, 'Notes 1', 111, '{"(7,Product 1,Description 1,12.24,2,0.0,{4})"}') $$,
+	$$ select add_invoice(1, 'INV001', '2023-02-15', 12, 'Notes 1', 111, '{tag1,tag2}','{"(7,Product 1,Description 1,12.24,2,0.0,{4})"}') $$,
 	'Should be able to insert an invoice for the first company with a product'
 );
 
 select lives_ok(
-	$$ select add_invoice(1, 'INV002', '2023-02-16', 13, 'Notes 2', 111, '{"(7,Product 1 bis,Description 1 bis,33.33,1,0.50,\"{4,3}\")","(8,Product 2,Description 2,24.00,3,0.75,{})"}') $$,
+	$$ select add_invoice(1, 'INV002', '2023-02-16', 13, 'Notes 2', 111, '{}', '{"(7,Product 1 bis,Description 1 bis,33.33,1,0.50,\"{4,3}\")","(8,Product 2,Description 2,24.00,3,0.75,{})"}') $$,
 	'Should be able to insert a second invoice for the first company with two product'
 );
 
 select lives_ok(
-	$$ select add_invoice(2, 'INV101', '2023-02-14', 15, 'Notes 3', 222, '{"(11,Product 4.3,,11.11,1,0.0,{6})"}') $$,
+	$$ select add_invoice(2, 'INV101', '2023-02-14', 15, 'Notes 3', 222, '{tag3}','{"(11,Product 4.3,,11.11,1,0.0,{6})"}') $$,
 	'Should be able to insert an invoice for the second company with a product'
 );
 
 select lives_ok(
-	$$ select add_invoice(1, NULL, '2023-03-15', 13, '', 111, '{"(7,PA1,DA1,44.33,1,0.50,{})"}') $$,
+	$$ select add_invoice(1, NULL, '2023-03-15', 13, '', 111, '{tag2}', '{"(7,PA1,DA1,44.33,1,0.50,{})"}') $$,
 	'Should be able to insert an invoice with an autogenerated number'
 );
 
 select lives_ok(
-	$$ select add_invoice(2, '  ', '2023-04-16', 14, '', 222, '{"(11,PA2,DA2,55.33,10,0.75,{})"}') $$,
+	$$ select add_invoice(2, '  ', '2023-04-16', 14, '', 222, '{tag2,tag3,tag4}','{"(11,PA2,DA2,55.33,10,0.75,{})"}') $$,
 	'Should consider non-null, but otherwise empty numbers the same as null and autogenerate it'
 );
 
@@ -138,6 +140,30 @@ select bag_eq(
 	'Should have created all invoice product taxes'
 );
 
+select bag_eq(
+	$$ select company_id, name from tag $$,
+	$$ values (1, 'tag1')
+	        , (1, 'tag2')
+		, (2, 'tag2')
+		, (2, 'tag3')
+		, (2, 'tag4')
+	$$,
+	'Should have added all new tags once'
+);
+
+select bag_eq(
+	$$ select invoice_number, tag.name from invoice_tag join invoice using (invoice_id) join tag using (tag_id) $$,
+	$$ values ('INV001', 'tag1')
+	        , ('INV001', 'tag2')
+	        , ('INV101', 'tag3')
+	        , ('F20230006', 'tag2')
+	        , ('INV056-23', 'tag2')
+	        , ('INV056-23', 'tag3')
+	        , ('INV056-23', 'tag4')
+	$$,
+	'Should have assigned the tags to invoices'
+);
+
 
 select *
 from finish();
diff --git a/test/invoice_tag.sql b/test/invoice_tag.sql
new file mode 100644
index 0000000..f97ab73
--- /dev/null
+++ b/test/invoice_tag.sql
@@ -0,0 +1,136 @@
+-- Test invoice_tag
+set client_min_messages to warning;
+create extension if not exists pgtap;
+reset client_min_messages;
+
+begin;
+
+select plan(23);
+
+set search_path to numerus, auth, public;
+
+select has_table('invoice_tag');
+select has_pk('invoice_tag' );
+select col_is_pk('invoice_tag', array['invoice_id', 'tag_id']);
+select table_privs_are('invoice_tag', 'guest', array []::text[]);
+select table_privs_are('invoice_tag', 'invoicer', array ['SELECT', 'INSERT', 'UPDATE', 'DELETE']);
+select table_privs_are('invoice_tag', 'admin', array ['SELECT', 'INSERT', 'UPDATE', 'DELETE']);
+select table_privs_are('invoice_tag', 'authenticator', array []::text[]);
+
+select has_column('invoice_tag', 'invoice_id');
+select col_is_fk('invoice_tag', 'invoice_id');
+select fk_ok('invoice_tag', 'invoice_id', 'invoice', 'invoice_id');
+select col_type_is('invoice_tag', 'invoice_id', 'integer');
+select col_not_null('invoice_tag', 'invoice_id');
+select col_hasnt_default('invoice_tag', 'invoice_id');
+
+select has_column('invoice_tag', 'tag_id');
+select col_is_fk('invoice_tag', 'tag_id');
+select fk_ok('invoice_tag', 'tag_id', 'tag', 'tag_id');
+select col_type_is('invoice_tag', 'tag_id', 'integer');
+select col_not_null('invoice_tag', 'tag_id');
+select col_hasnt_default('invoice_tag', 'tag_id');
+
+
+set client_min_messages to warning;
+truncate invoice_tag cascade;
+truncate invoice cascade;
+truncate tag cascade;
+truncate contact cascade;
+truncate company_user cascade;
+truncate company cascade;
+truncate payment_method cascade;
+truncate auth."user" cascade;
+reset client_min_messages;
+
+insert into auth."user" (user_id, email, name, password, role, cookie, cookie_expires_at)
+values (1, 'demo@tandem.blog', 'Demo', 'test', 'invoicer', '44facbb30d8a419dfd4bfbc44a4b5539d4970148dfc84bed0e', current_timestamp + interval '1 month')
+     , (5, 'admin@tandem.blog', 'Demo', 'test', 'admin', '12af4c88b528c2ad4222e3740496ecbc58e76e26f087657524', current_timestamp + interval '1 month')
+;
+
+set constraints "company_default_payment_method_id_fkey" deferred;
+
+insert into company (company_id, business_name, vatin, trade_name, phone, email, web, address, city, province, postal_code, country_code, currency_code, default_payment_method_id)
+values (2, 'Company 2', 'XX123', '', '555-555-555', 'a@a', '', '', '', '', '', 'ES', 'EUR', 222)
+     , (4, 'Company 4', 'XX234', '', '666-666-666', 'b@b', '', '', '', '', '', 'FR', 'USD', 444)
+;
+
+insert into payment_method (payment_method_id, company_id, name, instructions)
+values (444, 4, 'cash', 'cash')
+     , (222, 2, 'cash', 'cash')
+;
+
+set constraints "company_default_payment_method_id_fkey" immediate;
+
+insert into company_user (company_id, user_id)
+values (2, 1)
+     , (4, 5)
+;
+
+insert into contact (contact_id, company_id, business_name, vatin, trade_name, phone, email, web, address, city, province, postal_code, country_code)
+values (6, 2, 'Contact 1', 'XX555', '', '777-777-777', 'c@c', '', '', '', '', '', 'ES')
+     , (8, 4, 'Contact 2', 'XX666', '', '888-888-888', 'd@d', '', '', '', '', '', 'ES')
+;
+
+insert into invoice (invoice_id, company_id, invoice_number, contact_id, currency_code, payment_method_id)
+values (10, 2, 'INV020001', 6, 'EUR', 222)
+     , (12, 4, 'INV040001', 8, 'EUR', 444)
+;
+
+insert into tag (tag_id, company_id, name)
+values (14, 2, 'web')
+     , (15, 2, 'design')
+     , (16, 4, 'product')
+     , (17, 4, 'development')
+     , (18, 4, 'something-else')
+     , (19, 4, 'design')
+;
+
+insert into invoice_tag (invoice_id, tag_id)
+values (10, 14)
+     , (10, 15)
+     , (12, 18)
+;
+
+prepare invoice_tag_data as
+select invoice_id, tag_id
+from invoice_tag
+;
+
+set role invoicer;
+select is_empty('invoice_tag_data', 'Should show no data when cookie is not set yet');
+reset role;
+
+select set_cookie('44facbb30d8a419dfd4bfbc44a4b5539d4970148dfc84bed0e/demo@tandem.blog');
+select bag_eq(
+	'invoice_tag_data',
+	$$ values ( 10, 14 )
+	        , ( 10, 15 )
+	$$,
+	'Should only list invoice tags of the companies where demo@tandem.blog is user of'
+);
+reset role;
+
+select set_cookie('12af4c88b528c2ad4222e3740496ecbc58e76e26f087657524/admin@tandem.blog');
+select bag_eq(
+	'invoice_tag_data',
+	$$ values ( 12, 18 )
+	$$,
+	'Should only list invoice tags of the companies where admin@tandem.blog is user of'
+);
+reset role;
+
+select set_cookie('not-a-cookie');
+select throws_ok(
+	'invoice_tag_data',
+	'42501', 'permission denied for table invoice_tag',
+	'Should not allow select to guest users'
+);
+
+
+reset role;
+select *
+from finish();
+
+rollback;
+
diff --git a/test/tag.sql b/test/tag.sql
new file mode 100644
index 0000000..4163d56
--- /dev/null
+++ b/test/tag.sql
@@ -0,0 +1,139 @@
+-- Test tag
+set client_min_messages to warning;
+create extension if not exists pgtap;
+reset client_min_messages;
+
+begin;
+
+select plan(33);
+
+set search_path to numerus, auth, public;
+
+select has_table('tag');
+select has_pk('tag' );
+select table_privs_are('tag', 'guest', array []::text[]);
+select table_privs_are('tag', 'invoicer', array ['SELECT', 'INSERT', 'UPDATE', 'DELETE']);
+select table_privs_are('tag', 'admin', array ['SELECT', 'INSERT', 'UPDATE', 'DELETE']);
+select table_privs_are('tag', 'authenticator', array []::text[]);
+
+select has_sequence('tag_tag_id_seq');
+select sequence_privs_are('tag_tag_id_seq', 'guest', array[]::text[]);
+select sequence_privs_are('tag_tag_id_seq', 'invoicer', array['USAGE']);
+select sequence_privs_are('tag_tag_id_seq', 'admin', array['USAGE']);
+select sequence_privs_are('tag_tag_id_seq', 'authenticator', array[]::text[]);
+
+select has_column('tag', 'tag_id');
+select col_is_pk('tag', 'tag_id');
+select col_type_is('tag', 'tag_id', 'integer');
+select col_not_null('tag', 'tag_id');
+select col_has_default('tag', 'tag_id');
+select col_default_is('tag', 'tag_id', 'nextval(''tag_tag_id_seq''::regclass)');
+
+select has_column('tag', 'company_id');
+select col_is_fk('tag', 'company_id');
+select fk_ok('tag', 'company_id', 'company', 'company_id');
+select col_type_is('tag', 'company_id', 'integer');
+select col_not_null('tag', 'company_id');
+select col_hasnt_default('tag', 'company_id');
+
+select has_column('tag', 'name');
+select col_type_is('tag', 'name', 'tag_name');
+select col_not_null('tag', 'name');
+select col_hasnt_default('tag', 'name');
+select col_is_unique('tag', array['company_id', 'name']);
+
+
+set client_min_messages to warning;
+truncate tag cascade;
+truncate company_user cascade;
+truncate company cascade;
+truncate payment_method cascade;
+truncate auth."user" cascade;
+reset client_min_messages;
+
+insert into auth."user" (user_id, email, name, password, role, cookie, cookie_expires_at)
+values (1, 'demo@tandem.blog', 'Demo', 'test', 'invoicer', '44facbb30d8a419dfd4bfbc44a4b5539d4970148dfc84bed0e', current_timestamp + interval '1 month')
+     , (5, 'admin@tandem.blog', 'Demo', 'test', 'admin', '12af4c88b528c2ad4222e3740496ecbc58e76e26f087657524', current_timestamp + interval '1 month')
+;
+
+set constraints "company_default_payment_method_id_fkey" deferred;
+
+insert into company (company_id, business_name, vatin, trade_name, phone, email, web, address, city, province, postal_code, country_code, currency_code, default_payment_method_id)
+values (2, 'Company 2', 'XX123', '', '555-555-555', 'a@a', '', '', '', '', '', 'ES', 'EUR', 222)
+     , (4, 'Company 4', 'XX234', '', '666-666-666', 'b@b', '', '', '', '', '', 'FR', 'USD', 444)
+;
+
+insert into payment_method (payment_method_id, company_id, name, instructions)
+values (444, 4, 'cash', 'cash')
+     , (222, 2, 'cash', 'cash')
+;
+
+set constraints "company_default_payment_method_id_fkey" immediate;
+
+insert into company_user (company_id, user_id)
+values (2, 1)
+     , (4, 5)
+;
+
+insert into tag (company_id, name)
+values (2, 'web')
+     , (2, 'design')
+     , (4, 'product')
+     , (4, 'development')
+     , (4, 'something-else')
+     , (4, 'design')
+;
+
+prepare tag_data as
+select company_id, name
+from tag
+;
+
+set role invoicer;
+select is_empty('tag_data', 'Should show no data when cookie is not set yet');
+reset role;
+
+select set_cookie('44facbb30d8a419dfd4bfbc44a4b5539d4970148dfc84bed0e/demo@tandem.blog');
+select bag_eq(
+	'tag_data',
+	$$ values ( 2, 'web' )
+	        , ( 2, 'design' )
+	$$,
+	'Should only list tags of the companies where demo@tandem.blog is user of'
+);
+reset role;
+
+select set_cookie('12af4c88b528c2ad4222e3740496ecbc58e76e26f087657524/admin@tandem.blog');
+select bag_eq(
+	'tag_data',
+	$$ values (4, 'product' )
+	        , (4, 'development' )
+		, (4, 'something-else' )
+	        , (4, 'design' )
+	$$,
+	'Should only list tags of the companies where admin@tandem.blog is user of'
+);
+reset role;
+
+select set_cookie('not-a-cookie');
+select throws_ok(
+	'tag_data',
+	'42501', 'permission denied for table tag',
+	'Should not allow select to guest users'
+);
+reset role;
+
+select throws_ok( $$
+	insert into tag (company_id, name)
+	values (2, 'web')
+	$$,
+	'23505', 'duplicate key value violates unique constraint "tag_company_id_name_key"',
+	'Should not allow repeated tag names within the same company'
+);
+
+
+select *
+from finish();
+
+rollback;
+
diff --git a/test/tag_name.sql b/test/tag_name.sql
new file mode 100644
index 0000000..0397220
--- /dev/null
+++ b/test/tag_name.sql
@@ -0,0 +1,59 @@
+-- Test tag_name
+set client_min_messages to warning;
+create extension if not exists pgtap;
+reset client_min_messages;
+
+begin;
+
+select plan(12);
+
+set search_path to numerus, public;
+
+select has_domain('tag_name');
+select domain_type_is('tag_name', 'text');
+
+select lives_ok($$ select 'abcdefghijklmnopqrstuvwxyz012345678'::tag_name $$, 'Should be able to cast strings with up to 35 lowercase alphanumeric characters to tag_name');
+select lives_ok($$ select 'a'::tag_name $$, 'Should be able to cast strings with a single letter to tag_name');
+select lives_ok($$ select '1'::tag_name $$, 'Should be able to cast strings with a single number to tag_name');
+select lives_ok($$ select 'a-long-tag'::tag_name $$, 'Should be able to cast strings with dashes to tag_name');
+
+select throws_ok(
+	$$ SELECT 'abcdefghijklmnopqrstuvwxyz0123456789'::tag_name $$,
+	23514, null,
+	'Should reject tag names with more than 35 characters'
+);
+
+select throws_ok(
+	$$ SELECT 'aB'::tag_name $$,
+	23514, null,
+	'Should reject tag names with uppercase characters'
+);
+
+select throws_ok(
+	$$ SELECT 'a$'::tag_name $$,
+	23514, null,
+	'Should reject tag names with symbols'
+);
+
+select throws_ok(
+	$$ SELECT 'a a'::tag_name $$,
+	23514, null,
+	'Should reject tag names with spaces'
+);
+
+select throws_ok(
+	$$ SELECT '-aa'::tag_name $$,
+	23514, null,
+	'Should reject tag names starting with a dash'
+);
+
+select throws_ok(
+	$$ SELECT ''::tag_name $$,
+	23514, null,
+	'Should reject empty tag names'
+);
+
+select *
+from finish();
+
+rollback;
diff --git a/verify/add_invoice.sql b/verify/add_invoice.sql
index 4662ff7..c8e6807 100644
--- a/verify/add_invoice.sql
+++ b/verify/add_invoice.sql
@@ -2,6 +2,6 @@
 
 begin;
 
-select has_function_privilege('numerus.add_invoice(integer, text, date, integer, text, integer, numerus.new_invoice_product[])', 'execute');
+select has_function_privilege('numerus.add_invoice(integer, text, date, integer, text, integer, numerus.tag_name[], numerus.new_invoice_product[])', 'execute');
 
 rollback;
diff --git a/verify/invoice_tag.sql b/verify/invoice_tag.sql
new file mode 100644
index 0000000..5a59afb
--- /dev/null
+++ b/verify/invoice_tag.sql
@@ -0,0 +1,13 @@
+-- Verify numerus:invoice_tag on pg
+
+begin;
+
+select invoice_id
+     , tag_id
+from numerus.invoice_tag
+where false;
+
+select 1 / count(*) from pg_class where oid = 'numerus.invoice_tag'::regclass and relrowsecurity;
+select 1 / count(*) from pg_policy where polname = 'company_policy' and polrelid = 'numerus.invoice_tag'::regclass;
+
+rollback;
diff --git a/verify/tag.sql b/verify/tag.sql
new file mode 100644
index 0000000..e22603e
--- /dev/null
+++ b/verify/tag.sql
@@ -0,0 +1,14 @@
+-- Verify numerus:tag on pg
+
+begin;
+
+select tag_id
+     , company_id
+     , name
+from numerus.tag
+where false;
+
+select 1 / count(*) from pg_class where oid = 'numerus.tag'::regclass and relrowsecurity;
+select 1 / count(*) from pg_policy where polname = 'company_policy' and polrelid = 'numerus.tag'::regclass;
+
+rollback;
diff --git a/verify/tag_name.sql b/verify/tag_name.sql
new file mode 100644
index 0000000..8777cae
--- /dev/null
+++ b/verify/tag_name.sql
@@ -0,0 +1,7 @@
+-- Verify numerus:tag_name on pg
+
+begin;
+
+select pg_catalog.has_type_privilege('numerus.tag_name', 'usage');
+
+rollback;
diff --git a/web/template/invoices/index.gohtml b/web/template/invoices/index.gohtml
index 1312cd8..5dd6f49 100644
--- a/web/template/invoices/index.gohtml
+++ b/web/template/invoices/index.gohtml
@@ -30,7 +30,7 @@
             <th>{{( pgettext "Invoice Num." "title" )}}</th>
             <th>{{( pgettext "Customer" "title" )}}</th>
             <th>{{( pgettext "Status" "title" )}}</th>
-            <th>{{( pgettext "Label" "title" )}}</th>
+            <th>{{( pgettext "Tags" "title" )}}</th>
             <th>{{( pgettext "Amount" "title" )}}</th>
             <th>{{( pgettext "Download" "title" )}}</th>
             <th>{{( pgettext "Actions" "title" )}}</th>
@@ -69,7 +69,12 @@
                             </form>
                         </details>
                     </td>
-                    <td></td>
+                    <td>
+                        {{- range $index, $tag := .Tags }}
+                            {{- if gt $index 0 }}, {{ end -}}
+                            <a href="?tag={{ . }}">{{ . }}</a>
+                        {{- end }}
+                    </td>
                     <td class="numeric">{{ .Total|formatPrice }}</td>
                     <td class="invoice-download"><a href="{{ companyURI "/invoices/"}}{{ .Slug }}.pdf"
                                                     download="{{ .Number}}.pdf"
diff --git a/web/template/invoices/new.gohtml b/web/template/invoices/new.gohtml
index 652048d..233300f 100644
--- a/web/template/invoices/new.gohtml
+++ b/web/template/invoices/new.gohtml
@@ -20,8 +20,9 @@
                 {{ template "select-field" .Customer }}
                 {{ template "input-field" .Number }}
                 {{ template "input-field" .Date }}
-                {{ template "input-field" .Notes }}
+                {{ template "input-field" .Tags }}
                 {{ template "select-field" .PaymentMethod }}
+                {{ template "input-field" .Notes }}
 
                 {{- range $product := .Products }}
                     <fieldset class="new-invoice-product">
diff --git a/web/template/invoices/products.gohtml b/web/template/invoices/products.gohtml
index a7e700d..2423f67 100644
--- a/web/template/invoices/products.gohtml
+++ b/web/template/invoices/products.gohtml
@@ -21,6 +21,7 @@
                 {{ template "hidden-field" .Number }}
                 {{ template "hidden-field" .Date }}
                 {{ template "hidden-field" .Notes }}
+                {{ template "hidden-field" .Tags }}
 
                 {{- range $product := .Products }}
                     <fieldset>