Getting Started with the Relentify API

What this does

The Relentify API lets you programmatically create invoices, manage customers, pull reports, and automate your accounting workflows. This guide covers authentication, rate limits, and error handling so you can start integrating quickly.

When to use it

Use the API when you want to connect Relentify to your own systems, build custom integrations, or automate repetitive tasks.

Step by step

1. Go to Settings and select API Keys
2. Click Generate API Key to create a new key (prefixed with rly_)
3. Copy the key and store it securely — it will not be shown again
4. Set the Authorization header on all requests: Bearer rly_your_key_here
5. Use the base URL: https://accounting.relentify.com/api/v1
6. All request and response bodies use JSON — set Content-Type: application/json
7. Rate limits are 100 requests per minute per key — a 429 response means you should back off and retry
8. Errors return a JSON object with error (machine-readable code) and message (human-readable description):

{
  "error": "validation_error",
  "message": "The field 'email' is required."
}

9. To test without affecting live data, append ?test_mode=true to any request
10. Check the individual endpoint guides for request and response examples