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Invoice Ninja

Business Operations Free key (no card)

AuthenticationFree key (no card)
Rate limitNo enforced API rate limit on self-hosted instances

Documentation: api-docs.invoicing.co ยท Checked Sep 13, 2026

About

Invoice Ninja is an open-source invoicing platform you can self-host for free with full API access. The REST API covers invoices, clients, payments, and expenses. Note that the free hosted plan does not include API access, so free API use means running your own instance.

Details

Free to start. You may need a free key, but no credit card.

Auth: Free key (no card)

Rate limit: No enforced API rate limit on self-hosted instances

Verified: 2026-09-13

Best for: invoicing open-source self-hosted

Read the docs Back to catalog

Setup

  1. Install Invoice Ninja on your own server or local environment
  2. Complete the setup wizard and create your company profile
  3. Go to Settings > Account Management > API Tokens in the app
  4. Generate a personal API token
  5. Send it as an X-API-Token header in requests
  6. Call endpoints like /api/v1/invoices to manage billing data
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