Build invoicing into anything you ship.
Create clients, generate invoices, send PDFs, mark them paid — all via a clean REST API. Free test mode on every plan, including FREE.
Quickstart
Three curl calls to a working invoice. Replace $KEY with your test key.
curl -X POST https://hisabi.ai/api/v1/clients \
-H "Authorization: Bearer $KEY" \
-H "Content-Type: application/json" \
-d '{
"name": "Acme Inc.",
"email": "billing@acme.com",
"currency": "AED"
}'curl -X POST https://hisabi.ai/api/v1/invoices \
-H "Authorization: Bearer $KEY" \
-H "Content-Type: application/json" \
-d '{
"client_id": "<id from step 1>",
"due_date": "2026-12-01T00:00:00Z",
"currency": "AED",
"line_items": [
{
"description": "Web design",
"quantity": 1,
"unit_price": 500000,
"tax_rate": 5
}
]
}'curl https://hisabi.ai/api/v1/invoices/<id>/pdf \
-H "Authorization: Bearer $KEY"
# Returns: { "data": { "url": "...", "expires_at": "..." } }
# Fetch the URL within 5 minutes for the PDF bytes.curl -X POST https://hisabi.ai/api/v1/invoices/<id>/mark-paid \
-H "Authorization: Bearer $KEY"Keys prefixed hsb_test_ are unlimited and free on every plan. Test invoices are flagged test_mode: true, excluded from billing/analytics, and never email your clients.
Use them for development, demos, CI checks, sandboxes — anything but production.
Test invoices auto-expire and are deleted 30 days after creation. Live invoices are never deleted.
- FREE · 20 req/min, 500/day, 1 key
- STARTER · 60 req/min, 5k/day, 3 keys
- PROFESSIONAL · 120 req/min, 25k/day, 10 keys
- FIRM · 300 req/min, 100k/day, 25 keys
- All responses include
RateLimit-*headers.
FAQ
Developer API questions
Can't find what you're looking for? Contact us
Yes. The Free plan includes API access with 1 active key, 20 requests/min, and 500 requests/day, plus unlimited free test-mode keys for development, demos, and CI. Paid plans simply lift the rate limits and key count — the API itself is free to use on every tier.
Hisabi.ai ships a stable REST API at /api/v1 with bearer-key authentication, OpenAPI 3.1 spec, snake_case JSON, integer money fields in smallest currency units, IETF rate-limit headers, request IDs on every response, and an interactive Scalar reference at /developers. Workspace-scoped keys with granular scopes (clients:read, invoices:write, brand:write, etc.) and unlimited free test mode (hsb_test_* keys) let developers build, demo, and run CI without ever burning a real invoice.
Yes. Stripe Invoicing charges 0.4% per invoice plus standard Stripe processing fees. Hisabi.ai charges nothing per invoice on the API — only the flat plan price (Free, Starter, Professional, or Firm) — and the Free plan already includes production API access. For non-US businesses, Hisabi.ai is significantly cheaper than Stripe Invoicing, QuickBooks Online API, Xero API, or FreshBooks API.
Send Authorization: Bearer hsb_(live|test)_<32 hex>. Generate a key in Settings → API Keys; the raw key is shown to you once and stored only as a SHA-256 hash. The hsb_live_ / hsb_test_ prefix is a Stripe-style convention so GitHub secret scanning detects leaks automatically.
Keys prefixed hsb_test_ are unlimited and free on every plan. They produce real Invoice rows flagged test_mode: true, but those invoices are excluded from analytics, the monthly invoice cap, and outbound emails. Test mode is the recommended way to develop, demo, and run integration tests.
Test invoices auto-expire 30 days after creation. A daily cleanup job deletes them along with their line items and audit log rows. Live (production) invoices are never deleted. This keeps the FREE tier sustainable: developers get unlimited test mode, but storage growth stays bounded.
Any ISO-4217 currency. Pass currency: 'AED' / 'USD' / 'EUR' / 'GBP' / 'SAR' / 'INR' / etc. on the invoice. Money fields are integers in the smallest unit of the currency (fils for AED, cents for USD). Multi-currency invoices include automatic base-currency conversion at post time.
Yes. The full OpenAPI 3.1 spec is publicly available at https://hisabi.ai/api/v1/openapi.json and renders interactively at https://hisabi.ai/developers via Scalar. You can import it into Postman, Insomnia, Bruno, or auto-generate SDKs in any language using openapi-generator, Stainless, or Speakeasy.
Yes. Any HTTP-capable automation tool works today: Zapier 'Webhooks by Zapier', Make 'HTTP' module, n8n 'HTTP Request' node, Pipedream. Native first-party integrations for Zapier and Make are on the v1.1 roadmap.
API reference
Full reference rendered from the OpenAPI 3.1 spec. Try requests directly from the browser using a test key.