---
title: "SANDBOX: verify buyer -> create -> validate -> route -> transmit (mock or partner Peppol sandbox) -> signed evidence receipt"
method: POST
path: "/einvoice/send"
tags: ["E-invoice"]
---

# SANDBOX: verify buyer -> create -> validate -> route -> transmit (mock or partner Peppol sandbox) -> signed evidence receipt

`POST /einvoice/send`

## Request

- Base URL: `https://api.wsystem.dev`
- URL: `https://api.wsystem.dev/einvoice/send`
- Auth: none declared

One call for the whole e-invoice flow. Body: {"invoice": <same JSON as POST /einvoice/create>, "mode": "sandbox", "transport": "mock"}. Steps: VIES check of buyer.vat_id (invalid VAT stops the flow), sanctions screen of the buyer name, EN 16931 UBL creation + validation (invalid stops the flow), route lookup (Peppol Directory, country mandate, France PPF), transmission via a pluggable transport, and an Ed25519-signed evidence receipt (JWS; public key at GET /einvoice/evidence-key). SANDBOX ONLY. transport: 'mock' (default; transmits nothing), 'recommand' or 'e-invoice-be' (the validated Peppol BIS 3 UBL is really submitted to that Peppol access point's sandbox/playground and the partner document id is returned and signed into the receipt; it is addressed to W System's own sandbox company, never to the buyer, and does not reach the production Peppol network; transmission.transmitted stays false). Partner transports switch invoice.format to peppol-bis3. mode=live returns 501 until production Peppol sending is live. Free tier shared, then x402 $0.08 (same as create).

## Request body

- object

## Response `200`

Successful Response

- unknown

## Other responses

- `402`: Payment Required: x402 v2 challenge (PAYMENT-REQUIRED header). Returned when the free tier is used up, or for a bare call without input.
- `422`: Validation Error
- `429`: Free tier used up and x402 disabled

---

[API](https://skmtc.dev/wsystem/apis/w-system-eu-business-data-api-vat-vies-eori-company-registry.md) · [All operations](https://skmtc.dev/wsystem/apis/w-system-eu-business-data-api-vat-vies-eori-company-registry/llms.txt) · [OpenAPI document](https://skmtc.dev/wsystem/apis/w-system-eu-business-data-api-vat-vies-eori-company-registry/revisions/ab39146b346f?raw)