Greenstamp API Platform

Compliant e-invoicing infrastructure — one API for European Peppol

Greenstamp handles the hard compliance — European Peppol e-invoicing — so you can issue compliant invoices directly from your product or AI agent.

Get API keys

What you can build

Three integration surfaces — pick the one that fits your architecture

REST API

Full invoicing, AP, and treasury surface — ~25 OpenAPI-documented resources. Create, issue, cancel, and query invoices and bills with a single authenticated request.

MCP Server

Let AI agents draft invoices, read counterparties and ledger data, and request stamp actions — safely. Read-only by default; write operations require an explicit human-approval gate.

Webhooks

Subscribe an endpoint and receive signed, real-time events the moment things happen — invoice.stamped, invoice.paid, bill.paid, and 25+ more — with automatic retries and a full delivery log.

Up in one request

Authenticate with a Bearer token, pass entity and counterparty IDs, and get back a stamped invoice. Here's a Peppol example using the real endpoint shape:

bash

curl https://api.greenstamp.io/api/v1/invoices \
  -H "Authorization: Bearer $GREENSTAMP_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "entity_id":        "entt_...",
    "counterparty_id":  "cpty_...",
    "currency":         "EUR",
    "line_items": [{
      "description":  "Consulting services",
      "quantity":     1,
      "unit_price":   1000.00
    }]
  }'

Authentication & keys

API keys are org-scoped with per-resource permission scopes. Keys created for AI agents default to read-only; write operations (stamping, cancellations) require explicit elevated permissions with a human-approval gate. Get your keys from your API Keys dashboard.