Three steps. Sixty seconds. Zero spreadsheets.
No forms. No clicking around. Just tell your bot what to invoice and Billbot handles the rest. It’s almost unfair how easy this is.
Grab an API key
Sign up, go to Settings, click "Generate". That's 30 seconds of your life. We're sorry. It won't happen again.
Your API key starts with bb_ and works immediately. Use it as a Bearer token in the Authorization header. That's it. No OAuth flow. No client secrets. No tears.
Feed it to your bot
Give your AI agent the API key + the OpenAPI spec URL. It reads the spec and immediately knows every trick Billbot can do.
Billbot provides an OpenAPI spec, llms.txt, and an MCP server. Most AI agents read these and start creating invoices with zero configuration. Your bot figures it out faster than you would.
"Invoice Acme for 10h of dev work"
Your agent creates the invoice, generates the PDF, and sends you the download link. Done. Like magic, but with JSON.
The entire flow — creating the client, adding line items, calculating totals, generating the PDF — happens in one API call chain. Your agent orchestrates it all while you do literally anything else.
Four ways in. Zero friction.
REST, MCP, OpenAPI, or plain text — Billbot speaks every dialect your agent knows.
REST API
Full CRUD. Clean JSON. Proper error codes. The kind of API that makes your bot feel loved.
MCP Server
Model Context Protocol — your AI agent calls Billbot tools directly. Like giving your bot a phone number.
OpenAPI Spec
Machine-readable spec at /api/openapi. Point your bot here and watch it auto-discover everything.
llms.txt
A plain text file at /llms.txt that explains Billbot to any AI. Think of it as a README for robots.
I used to spend Sunday evenings writing invoices. Now I tell Claude “invoice Render Labs for January — 42 hours at €95” and it’s done before I finish my coffee.
Lukas Meier
Freelance Full-Stack Developer, BerlinReady to automate your invoicing?
Sign up in 30 seconds. Generate an API key. Let your agent do the rest.