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Create and send sevdesk invoices from a short brief

You know what to bill after a call, but writing the invoice means finding the contact, typing every position, picking the tax rate and choosing the send option, all in the invoice mask.

Cotlet does it in your own sevdesk account with list_contacts, create_contact, create_invoice_draft, get_invoice and send_invoice, called by your AI agent, an n8n workflow or a script.

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Hosted · nothing to install or maintain

Can sevdesk do this on its own?

sevdesk creates invoices in its web mask and, on the Buchhaltung Pro plan, through saveInvoice and sendViaEmail (checked 14 Oct 2026). Both routes need the positions, tax rate and send format spelled out by you. Nothing in sevdesk turns a short brief into a draft you can read before it goes out.

How you do it in sevdesk today

  1. Go to Rechnungen and click Rechnung erstellen at the top right. sevdesk opens the invoice mask.
  2. Type the first letters in the field Kontakt and pick the customer. If you enter a new name, sevdesk creates the contact in the background.
  3. In the section Produkte, choose Brutto or Netto first, then fill Position, Menge, Einheit, Einzelpreis and USt. for each line.
  4. For an e-invoice, switch on the toggle E-Rechnung. The email address of the contact is then required.
  5. Finish with Versenden / Drucken / Herunterladen and choose Als E-Mail versenden. The invoice becomes open and the invoice number is fixed.

How to create and send sevdesk invoices from a short brief

Prompt

Create an invoice for Nordlicht Studio: website relaunch phase 2 for 1,200 EUR and 3 workshop days at 150 EUR, 19% VAT. Show me the draft, and when I say go, send it as an e-invoice.
  1. 01

    Find or create the contact

    list_contacts searches the name. If there is no match, create_contact adds the customer with the category you named, so the invoice is not created for a stray name typed into the mask.

  2. 02

    Build the draft, send nothing

    create_invoice_draft takes the positions from your brief with price mode net or gross, unit price and tax rate. The result is a draft, not a sent invoice, and the agent stops here for your review.

  3. 03

    Read the draft back

    get_invoice returns the positions and totals as sevdesk calculated them. The agent compares them with your brief, so a net price typed as gross is caught before the customer sees it.

  4. 04

    Check the e-invoice needs

    If you asked for an e-invoice, the agent checks that the contact has an email address. A missing one is reported, not guessed, because sevdesk requires it.

  5. 05

    Send after your go

    send_invoice finishes the invoice and emails it, as a PDF with the XML inside (ZUGFeRD) or as XML only (X-Rechnung). It always asks first by default, because the invoice number is final from that moment.

What you get back

Example data

Draft RE-1043 for Nordlicht Studio
1 x Website relaunch, phase 2: 1,200.00 EUR
3 x Workshop day: 450.00 EUR
Net 1,650.00 EUR, VAT 19% 313.50 EUR, total 1,963.50 EUR
E-invoice on, contact email present
Waiting for your go to send

Other ways to ask

  • Create the invoice for the same customer as last month and change the workshop days to 4, but do not send it.
  • Bill every contact in the category Kunde the same 49 EUR monthly fee and show me all drafts first.
  • Send the draft RE-1043 as XML only because the customer is a public body.
  • Create the draft in gross prices, because this customer is a private person.

What sevdesk allows, and what to know first

  • The invoice number in a draft is not final: sevdesk assigns it when the invoice is finished, in the order the invoices are sent.
  • Several drafts can show the same invoice number until they are sent, so a draft number must not be quoted to the customer.
  • E-invoices need your VAT ID in the company settings, and the email address of the recipient is a required field.
  • The Leitweg-ID is needed only for public clients such as authorities; for normal business invoices sevdesk sets the customer reference to 0.
  • An invoice cannot have a negative total in sevdesk; use a cancellation invoice or a credit note instead.

send_invoice asks for your OK by default. To run it on a schedule without you, switch confirmation off for that tool in your dashboard.

Sources: sevdesk Help: Rechnung erstellen · sevdesk Help: Rechnungsversand · sevdesk Help: E-Rechnung (versenden) · sevdesk Help: Rechnungsnummern im Entwurfsmodus · sevdesk Help: Rechnungen Produkte

Call send_invoice from a script

curl

curl -X POST https://cotlet.dev/api/v1/sevdesk/invoices/41873190 \
  -H "Authorization: Bearer $COTLET_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"to_email":"accounts@nordlicht-studio.example","subject":"Invoice RE-1043","message":"Hello, please find our invoice RE-1043 attached. Payment is due within 14 days.","format":"zugferd_pdf"}'

Example response

{
  "invoice_id": "41873190",
  "invoice_number": "RE-1043",
  "status": "open",
  "sent_to": "accounts@nordlicht-studio.example",
  "format": "zugferd_pdf",
  "sent_at": "2026-10-14T10:42:00+02:00"
}

MCP: add https://cotlet.dev/mcp/v1 with the same key; the call is sevdesk_write → send_invoice. Example data.

Schedule it in n8n, Make, Zapier or cron

sevdesk tools this automation uses

Cotlet sevdesk tools used to create and send sevdesk invoices from a short brief
Tool Parameters
list_contacts search, category, customer_number, limit, cursor
create_contact kind, name, first_name, last_name, category, email, street, zip, city, country
create_invoice_draft contact_id, positions, price_mode, invoice_date, subject, e_invoice, customer_reference
get_invoice invoice_id
send_invoice invoice_id, to_email, subject, message, format, copy_to_me
All 14 sevdesk tools with descriptions

Frequently asked questions

Is it safe to connect sevdesk to Cotlet?

Yes. You sign in to sevdesk yourself, in your own Cloud Browser in the EU, and we never save your password. Your agents only get sevdesk once you enable it, every background request is listed, and the browser profile is stored encrypted with AES-256-GCM, the cipher 1Password uses for its vaults. The AI model never sees a login, posts and messages wait for your OK, and Disable for agents cuts access in one click. Independent scanners grade cotlet.dev A+ on Qualys SSL Labs, securityheaders.com and Mozilla Observatory; live results are on https://cotlet.dev/security.

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