FacturaHub's API is a REST API that lets you run your entire invoicing from your code, without going through the dashboard: you create invoices, clients, expenses and declarations, emit Verifactu and query metrics, all with JSON over HTTPS. It's the same backend the web app, the WhatsApp agent and the MCP server use, so any data you create via API shows up instantly across all three channels.
Authentication is dual and you pick based on your case:
x-api-key — your key in the header. Most convenient for server-to-server integrations (scripts, cron, your own backend). You generate it from your account settings.Authorization: Bearer <JWT> — a JWT token. Use it if you already have a user session.The endpoints cover the whole business. Each resource supports the usual REST operations (GET to list/read, POST to create, PATCH/PUT to update, DELETE to remove):
/api/invoices — invoices/api/clients — clients and CRM/api/expenses — expenses (with OCR scanning)/api/catalog — products and services/api/tasks — tasks/api/teams — teams and permissions/api/vendors and /api/supplier-invoices — vendors and received invoices/api/tax-declarations — Modelo 303 and other declarations/api/einvoice — e-invoicing (Verifactu in Spain)/api/cash-register — cash register/api/context — your business's living memory shared with the AIcurl -X POST https://api.facturahub.com/api/invoices \
-H "x-api-key: YOUR_API_KEY" \
-H "Content-Type: application/json" \
-d '{
"client": { "name": "Acme SL", "taxId": "B12345678", "country": "ES" },
"items": [{ "description": "Consulting", "quantity": 1, "unitPrice": 1000 }],
"taxRate": 21,
"retentionRate": 15,
"issueDate": "2026-06-18"
}'To emit an e-invoice in Spain, you first create the invoice and then emit it with POST /api/einvoice (or the legacy Verifactu endpoint): FacturaHub signs the record, sends it to the AEAT via Verifactu and returns the fiscal id, QR and status. For quarterly IVA, POST /api/tax-declarations/generate with {country:"ES", year, period} returns all Modelo 303 boxes calculated from your real invoices and expenses — ready for you or your accountant to file.
The whole API is documented and browsable:
https://facturahub.com/openapi.json — importable into Postman, Insomnia or any SDK generator.https://facturahub.com/api-docs/ — try endpoints from the browser.https://github.com/Santy1422/facturahub-api — code in cURL, JavaScript, Python and PHP.The plan is free and everything is unlimited: invoices, clients, expenses, API calls, Verifactu, Modelo 303 and CSV and PDF export. The only thing metered is AI: 25 free AI actions per month (for example a receipt OCR), and if you need more you buy a one-off token pack from €4.99 that never expires. There are no Starter/Growth/Pro plans or 7-day trial, and creating invoices or clients via the plain API doesn't consume AI.
Honest about what isn't ready yet (we don't announce it as available):
invoice.paid calling your URL when something changes./v1 — today the API lives under /api.In the meantime, you work against your real account and can use draft invoices to test without emitting anything fiscal.
Create, read, update and delete resources with standard HTTP. Same backend as the web, WhatsApp and MCP: what you create via API appears instantly across all three.
Use your API key in the x-api-key header for server-to-server integrations, or a JWT token in Authorization: Bearer if you already have a user session.
invoices, clients, expenses, catalog, tasks, teams, vendors, supplier-invoices, tax-declarations, e-invoice, cash-register and context. Full invoicing by API.
Create the invoice and emit it with POST /api/einvoice. FacturaHub signs the record, sends it to the AEAT via Verifactu and returns fiscal id, QR and status.
POST /api/tax-declarations/generate with {country:"ES", year, period} returns all 303 boxes calculated from your real data.
Public spec at facturahub.com/openapi.json (importable into Postman/Insomnia) and a browsable Swagger UI at facturahub.com/api-docs to test from the browser.
Public repository with examples in cURL, JavaScript, Python and PHP: github.com/Santy1422/facturahub-api.
Public testing sandbox, outbound webhooks (invoice.paid and similar) and a versioned base path /v1. Honestly: not yet, they're on the roadmap.
Two ways: with your API key in the x-api-key header (ideal for scripts and servers), or with a JWT token in Authorization: Bearer (if you already have a user session). You generate your key from your account settings.
The OpenAPI 3.1 spec is at facturahub.com/openapi.json and the browsable Swagger UI at facturahub.com/api-docs. There are cURL, JavaScript, Python and PHP examples in the GitHub repo: github.com/Santy1422/facturahub-api.
Practically the whole business: invoices, clients, expenses, product catalog, tasks, teams, vendors and received invoices, tax declarations (Modelo 303), e-invoicing (Verifactu), cash register and business context.
Yes. You create the invoice and emit it with POST /api/einvoice. FacturaHub signs the record, sends it to the AEAT via Verifactu and returns the fiscal id, QR and status of the e-invoice.
Not yet, and we prefer to be honest: the public sandbox, outbound webhooks (invoice.paid and similar) and a versioned base path /v1 are on the roadmap as coming soon. In the meantime you can test with draft invoices, which don't emit anything fiscal.
Nothing: the plan is free and API calls are unlimited. Only AI is metered — 25 free AI actions per month (like a receipt OCR) and one-off token packs from €4.99 if you need more. Creating invoices or clients via the plain API doesn't consume AI.
Yes. The API uses the same backend as the web, the WhatsApp agent and the MCP server. What you create via API appears instantly in the dashboard and vice versa: a single data source for all channels.