Accounting

fastbill integrations

Connect fastbill to any other app, or use it from your AI client over MCP. 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

You'll sign in before anything runs. What you typed comes with you.

Connect your AI client

Give your AI client this address.

https://mcp.apiant.ai

One connection does both: ask your client to act in an app once, or have it build an automation that keeps running. 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 (opens in a new tab)
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 (opens in a new tab)
Cursor

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

Setup guide (opens in a new tab)
Zed

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

Setup guide (opens in a new tab)
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 (opens in a new tab)
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 (opens in a new tab)

Popular

fastbill with the apps people pair it with most

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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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Questions

fastbill, answered

Is there a fastbill MCP server?

APIANT's MCP server at https://mcp.apiant.ai works with fastbill. Add that address to any AI client that takes a remote MCP server and sign in once in your browser. Your client can then run fastbill actions on demand, or have APIANT build, test and run automations that use fastbill. Nothing to install.

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.

Can I use fastbill directly from Claude, ChatGPT or Cursor?

Yes. Connect your AI client to APIANT once and it works with fastbill two ways. Ask it to do something in fastbill once and it runs that action on the spot. Ask for an automation and your agent builds it, tests every scenario and keeps it running on its own. A one-off action uses your plan's tasks the same way an automation step does.

Do I need to write code against the fastbill API?

No. APIANT connects to the fastbill API for you, with your fastbill API key. Describe what you want in plain language and your agent builds it on the fastbill triggers and actions in the catalog. If you need an endpoint that is not there yet, your agent reads the fastbill API documentation and adds it.

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.