Connect fastbill to any app

FastBill is a cloud app for German invoicing & accounting. Writing offers and invoices, paying your bills or preparing your tax return is easier than ever with FastBill.

Connects with an API keyfastbill.com

18 actions

What the catalog holds today. Ask for anything missing and your agent reads the API documentation and adds it.

Build solutions, not workarounds.

What do you want to automate with fastbill?

Ask the assistant

Connect your AI client

Give your AI client this address.

https://mcp.apiant.ai

Any client that takes a remote MCP server. Nothing to install. Create your free account, then sign in once in your browser.

Set it up in your client

Claude Code

Run this in the directory you want to work in.

claude mcp add --transport http -s project apiant-ai https://mcp.apiant.ai

Start Claude Code there, approve the server, and sign in in the browser page it opens.

Claude Code guide

Claude, web and desktop

Open Customize, then Connectors, then Add custom connector, and paste the address. On Team and Enterprise an owner adds it first.

Setup guide

Cursor

Add the address to your MCP configuration as a server URL. Cursor signs you in in your browser.

Setup guide

Zed

Open Settings, then AI, then MCP Servers, then Add Server, then Add Remote Server.

Setup guide

Codex and the ChatGPT desktop app

Open Settings, then MCP servers, then Add server, and choose Streamable HTTP. From the terminal, Codex takes the address with its own add command and then signs you in.

Setup guide

Any other MCP client

Paste the address where the client asks for a remote MCP server URL, and name the server apiant-ai where it lets you. APIANT's skills reach the client over the same connection.

Setup guide

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What your agent can do with fastbill

Triggers and actions 18 actions

Action
Add Payment for Invoice
Adds full payment for invoice
Action
Add Payment for Revenue
Adds full payment for revenue
Action
Create Customer
Creates a new customer in FastBill
Action
Create Invoice
Creates a new invoice
Action
Create Offer
Creates a new offer in FastBill
Action
Create Revenue
Creates a revenue entry
Action
Delete Customer
Delete a FastBill customer by ID.
Action
Delete Invoice
Delete a FastBill invoice by ID.
Action
Delete Offer
Delete a FastBill offer/estimate by ID.
Action
Finalize Invoice
Converts an invoice draft to a final invoice
Action
Get Customer
Fetch a single FastBill customer by ID.
Action
Get Invoice
Fetch a single FastBill invoice by ID.
Action
Get Offer
Fetch a single FastBill offer/estimate by ID.
Action
Search Customer
Search for a Customer
Action
Search Invoice
Find an invoice
Action
Send Invoice by Email
Send an invoice by email
Action
Update Customer
Update fields on an existing FastBill customer.
Action
Update Invoice
Update fields on an existing (draft) FastBill invoice.

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What our customers say

Questions

fastbill, answered

What can your agent do in fastbill?

Any of fastbill's 18 actions, including Create Customer, Create Invoice, Create Offer and Create Revenue. Your agent maps the data both ways and tests every scenario before it ships.

Which apps can fastbill connect to?

Any app in the catalog; the list on this page pairs fastbill with each of them. If the other app is missing, point your agent at its API documentation and it builds the connector.

What happens when something fails?

Your agent works that out for you. It plans the failure paths along with the happy path, then tests every scenario before it ships.

Is there a free plan?

Yes. Every plan includes the agent, including free, and building from your own AI client spends no assistant credits.