Billomat

Billomat is German online invoicing and accounting. Agents manage clients, suppliers, and articles, issue invoices with items and payments, send estimates, create credit notes, and log incoming supplier invoices.

58 actions API key available

Billomat website Platform Documentation Capability data verified 2026-08-24

A month of billable work closes and the recurring charges are due

List Clients returns the accounts to bill with their own price basis and tax rule

Create Invoice writes the draft with its items supplied inline

Get Invoice reads the stored document back and the agent compares the totals against what it sent

The price basis and the client's tax rule are confirmed to match the figures the totals imply

Complete Invoice assigns the number and renders the PDF, then Send Invoice By Email delivers it

Anything whose read back total disagrees with the source stops and goes to the biller

What This Integration Enables

Billomat covers German online invoicing end to end: clients and their contacts, suppliers, an article catalog, invoices with items, payments and comments, estimates, credit notes, incoming supplier invoices and recurring billing. FlowRunner agents run all of it, and the aggregated listing is worth calling out early, because Billomat can group a listing by client, month or status and hand back totals rather than records. A dashboard that would otherwise mean paging the whole ledger becomes one call.

The reason to think carefully before pointing an agent at this API is a specific politeness in how it accepts writes. Billomat expects every write body wrapped in its resource name, and a body sent unwrapped is accepted with a success response and changes nothing. That is the worst failure an API can have, because there is no error to catch and no exception to route. FlowRunner's connectors are built and verified against each vendor's official API, so the wrapping is handled for you, but the lesson generalizes past the wrapper: on this platform, a write is not proved by its response. It is proved by reading the record back, and that is how the workflows below are built.

Without FlowRunner

Writes trusted because they returned 200 A write that changed nothing looks identical to a write that worked, and the difference shows up at close

Totals that depend on a hidden setting Net or gross is a client level default nobody looks at, and a document totals differently with no error

Cleanup by deletion Correcting a bad invoice means deleting it, which takes its PDF, its items and its comments with it

With FlowRunner

Writes proved by reading back The agent reads the record it just wrote and compares it against the source before moving on

The setting is read, not assumed The client's price basis and tax rule are pulled before the document is built, so the totals are intended

Cleanup by cancellation Canceling keeps the numbering sequence and stays reversible, and deletion becomes a decision a person makes

Use Case Scenarios

Recurring billing that reconciles itself

At the start of the cycle, the agent reads List Recurrings and Get Recurring to see what is scheduled and Add Recurring Item to reflect a plan change agreed upstream in a system like Chargebee. It creates each invoice with Create Invoice, supplying items inline because that is the only place inline items work, then reads each one back with Get Invoice before Complete Invoice assigns a number. Payments arriving from Stripe are matched against List Invoices filtered to open and overdue, then recorded with Create Invoice Payment. Nothing gets completed on the strength of a create response alone.
A dashboard that costs one call

Finance wants revenue by client by month without waiting for the accountant. The agent runs the invoice listing grouped by client and year, which returns aggregated totals instead of records, and writes the result into Google Sheets. Because the grouping happens on Billomat's side, the flow does not page through a year of documents, which matters when the account is rate limited to a fixed number of requests inside each quarter hour window. The same job posts a short summary into Slack on the first working day of the month.
The supplier inbox that stops at the classification it cannot make

Supplier PDFs arrive by email or through Dext. The agent reads each one, matches or creates the supplier, and records it with Create Incoming. When the bank feed shows the money leaving, Create Incoming Payment books the settlement. Invoices whose supplier is new, whose amount sits outside the range that supplier has ever billed, or whose expense classification is genuinely ambiguous become automation exceptions instead of guesses. The bookkeeper sees a queue of things that needed a person, not a queue of everything.

Human-in-Loop Highlight

Billomat gives an agent two ways to make an invoice go away and only one of them is survivable. Cancel Invoice voids the document while keeping the numbering sequence intact, and Uncancel Invoice puts it back, so cancellation is a decision that can be revisited. Delete Invoice destroys the document along with its PDFs, its items and its comments, and there is no matching undo anywhere in the action list. Both are one call. So when a flow decides an invoice should not stand, it stops rather than choosing: "Invoice RE-2026-0338 for Kellner Systemtechnik, 12,400.00 EUR, completed on 3 March, one payment of 4,000.00 recorded against it, three comments. It appears to duplicate RE-2026-0331. Cancel it, which is reversible and keeps the number, or delete it, which is not?" The agent already gathered the evidence: the suspected duplicate, the payment, the comment history. What it declines to do is pick the verb whose consequences it cannot undo.

Agent processes routinely

Detects exception requiring judgment

Clear match Continues automatically

Ambiguous Routes to human via preferred channel

Human decides

Agent resumes with decision

Agent Capabilities

58 actions

Account

Get Own Company Reads the account's own company record, which Billomat stores as a special client.
List Taxes Lists the tax rates configured on the account.
List Units Lists the units of measure an article or a line can carry.
List Templates Lists the document templates available.
List Email Templates Lists the saved email wordings a send can use.

Clients

List Clients Lists clients with filters and paging. It also supports grouping, which turns the listing into totals rather than records.
Get Client Retrieves a single client, including its price basis and tax rule.
Create Client Creates a client. Its tax rule decides whether VAT is always charged, never charged, or derived from the country.
Update Client Updates a client record.
Delete Client Deletes a client.
List Client Contacts Lists the people attached to a client.
Create Client Contact Adds a person to a client, which is how an invoice reaches a named recipient.
Delete Client Contact Removes a person from a client.

Articles

List Articles Lists the catalog with prices and tax rates.
Get Article Retrieves a single catalog article.
Create Article Adds an article to the catalog.
Update Article Updates a catalog article.
Delete Article Removes a catalog article.

Suppliers

List Suppliers Lists suppliers on the account.
Create Supplier Creates a supplier record.
Delete Supplier Removes a supplier record.

Invoices

List Invoices Lists invoices with status and payment type filters, and with the grouping that returns aggregated totals.
Get Invoice Retrieves a single invoice. The read that proves a write actually landed.
Create Invoice Creates an invoice as a draft with an empty number. Items supplied here are the only inline item set the API accepts.
Update Invoice Updates a draft invoice's header. It does not touch items or comments.
Complete Invoice Assigns the number, moves the invoice to open and renders the PDF. Before this runs there is nothing for the PDF download to fetch.
Cancel Invoice Voids a completed invoice while preserving the numbering sequence.
Uncancel Invoice Reverses a cancellation, which is what makes canceling the recoverable choice.
Delete Invoice Destroys an invoice along with its PDFs, items and comments. The operation this page's human gate exists for.
Send Invoice By Email Emails the invoice to the client using a saved wording or your own.
Download Invoice PDF Fetches the rendered PDF, which exists only after the invoice is completed.
List Invoice Items Lists the lines on an invoice.
Add Invoice Item Adds a line to a draft invoice.
Delete Invoice Item Removes a line from a draft invoice.
List Invoice Payments Lists the settlements recorded against an invoice.
Create Invoice Payment Records a settlement. It works only on an open or overdue invoice, never on a draft or a paid one.
Delete Invoice Payment Removes a recorded settlement.
Add Invoice Comment Adds a comment to an invoice, which is where an agent records why it did what it did.

Estimates

List Estimates Lists estimates with their status.
Get Estimate Retrieves a single estimate.
Create Estimate Creates an estimate as a draft.
Complete Estimate Assigns the estimate's number and renders it.
Set Estimate Outcome Records the estimate as won, lost or cleared, or reverses any of those.
Send Estimate By Email Emails the estimate to the client.
Download Estimate PDF Fetches the rendered estimate PDF.
Delete Estimate Removes an estimate.

Credit notes

List Credit Notes Lists credit notes on the account.
Create Credit Note Creates a credit note as a draft.
Complete Credit Note Assigns the credit note's number and renders it.
Download Credit Note PDF Fetches the rendered credit note PDF.
Delete Credit Note Removes a credit note.

Incomings

List Incomings Lists recorded supplier invoices.
Create Incoming Records a supplier invoice against a supplier.
Delete Incoming Removes a recorded supplier invoice.

Payments

Create Incoming Payment Records the settlement of a supplier invoice.

Recurrings

List Recurrings Lists the recurring billing definitions on the account.
Get Recurring Retrieves a single recurring definition with its schedule.
Add Recurring Item Adds a line to a recurring definition, which is how a plan change reaches next month's invoice.

Frequently Asked Questions

What can FlowRunner do with Billomat?

FlowRunner agents can run Get Own Company, List Taxes, and List Units in Billomat, plus 55 more actions.

Does connecting Billomat to FlowRunner require OAuth?

No. Billomat connects to FlowRunner with an API key, no OAuth flow required.

Can Billomat trigger a FlowRunner workflow automatically?

Billomat doesn't currently expose triggers in FlowRunner. It connects as an action step inside workflows started by another trigger.

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