> ## Documentation Index
> Fetch the complete documentation index at: https://docs.pasca.name.ng/llms.txt
> Use this file to discover all available pages before exploring further.

# Status and validation

> Check invoice state and validate data

## Validation

Use schema validation to confirm your payload is compliant before signing. Use IRN validation to confirm IRN ownership and format.

## Status checks

* Lookup IRN status with `GET /api/v1/einvoice/lookup/{IRN}`.
* Fetch invoice details with `GET /api/v1/einvoice/{IRN}` or the simplified view with `GET /api/v1/einvoice/{IRN}/simple`.

## Updates

Use `PATCH /api/v1/einvoice/update/{IRN}` to update payment status and reference data after issuance.