Factuarea Node.js / TypeScript SDK

The official TypeScript SDK for the Factuarea API — Spanish e‑invoicing, VeriFactu, quotes, delivery notes and more.

It wraps the full v1 REST API (234 operations across 17 resources) with a premium runtime: automatic retries, automatic idempotency keys, transparent cursor auto‑pagination, a typed error hierarchy, typed webhook verification and binary (PDF) downloads. Ships as dual ESM + CommonJS with full type declarations.

Status: 0.x (pre‑GA). The public surface is stable and SemVer‑protected, but minor breaking changes may occur before 1.0.0 (which tracks the API's GA event).

Installation

npm install @factuarea/sdk

Requires Node 20 or newer. The SDK is runtime‑agnostic (built on the Web fetch standard) and also runs on Deno, Bun and Cloudflare Workers.

Quickstart

import { Factuarea } from "@factuarea/sdk";

const factuarea = new Factuarea({ apiKey: process.env.FACTUAREA_API_KEY! });

// Create an invoice
const invoice = await factuarea.invoices.create({
  client_id: "01931b3e-7c4a-7f2e-9a8b-3c5d6e7f8a9b",
  series_id: "01931b3e-7c4a-7f2e-9a8b-000000000001",
  issue_date: "2026-06-05",
  lines: [
    { description: "Consulting", quantity: 1, unit_price: 1000, taxes_id: "..." },
  ],
});

// List with transparent auto-pagination
for await (const inv of await factuarea.invoices.list({ status: "paid" })) {
  console.log(inv.id);
}

// Download a PDF
const pdf = await factuarea.invoices.pdf(invoice.id);
await require("node:fs/promises").writeFile("invoice.pdf", pdf.toBuffer());

Server‑side only. Your API key is a secret. Never ship it to a browser or a public client — use this SDK from your backend.

Authentication & environments

Pass your API key to the constructor. The key prefix selects the environment — there is no separate flag:

| Prefix | Environment | Effects | | ------------- | ----------- | ---------------------------------------------------- | | fact_test_… | Sandbox | Isolated test company; no real VeriFactu/email/webhooks | | fact_live_… | Production | Real data and side effects |

const sandbox = new Factuarea({ apiKey: "fact_test_…" });
sandbox.environment; // "test"

const prod = new Factuarea({ apiKey: "fact_live_…" });
prod.environment;    // "live"

Configuration

new Factuarea({
  apiKey: "fact_live_…",        // required
  baseUrl: "https://api.factuarea.com/v1", // override for self-hosted/staging
  timeout: 60_000,              // per-request timeout in ms (default 60s)
  maxRetries: 2,                // retry attempts after the first try (default 2)
  factuareaVersion: "2026-06-04", // pinned API version header (default: this release's)
  defaultHeaders: {},           // extra headers on every request
});

The SDK pins the Factuarea-Version header to the API version this release was built against, so the API's behaviour stays stable until you upgrade the SDK.

Resources

Every operation is reachable as factuarea.<resource>.<method>(), following the SDK method‑naming contract. Resources: account, clients, suppliers, products, invoices, quotes, proformas, deliveryNotes, purchaseInvoices, recurringInvoices, series, taxes, taxReports, verifactu, events, eventCatalog, webhookEndpoints. Nested groups too (e.g. factuarea.products.gallery.upload(...), factuarea.deliveryNotes.publicLink.update(...)).

Pagination

List methods return a Page, which is itself an async iterable. Iterate everything, or walk page by page:

const page = await factuarea.clients.list({ limit: 50 });

// (a) iterate all items across all pages
for await (const client of page) {
  console.log(client.id);
}

// (b) page-by-page
page.data;       // items on this page
page.hasMore;    // boolean
page.nextCursor; // opaque cursor or null
const next = await page.getNextPage(); // Page | null

// (c) collect everything into an array
const all = await page.toArray();

The SDK manages cursors for you using the API's next_cursor / has_more.

Automatic retries

Transient failures — 429 (rate limit), 5xx and network errors — are retried automatically with exponential backoff and full jitter, honouring the Retry-After header. Deterministic client errors (e.g. 422 validation) are never retried and surface immediately. Tune with maxRetries (globally or per request).

Idempotency

Every POST automatically gets an Idempotency-Key (UUID), so a retried request never double‑creates a resource. The same key is reused across the retries of one logical call. Override per request:

await factuarea.invoices.create(body, { idempotencyKey: "order-4711" });

Typed errors

Errors map the API's error envelope to a typed hierarchy. Every error exposes .code, .type, .requestId and .status.

import {
  FactuareaError,
  ValidationError,
  AuthenticationError,
  NotFoundError,
  ConflictError,
  RateLimitError,
  ServerError,
  ConnectionError,
} from "@factuarea/sdk";

try {
  await factuarea.invoices.create(body);
} catch (error) {
  if (error instanceof ValidationError) {
    console.error(error.fields);     // { tax_id: ["NIF inválido"], … }
  } else if (error instanceof RateLimitError) {
    console.error(error.retryAfter); // seconds to wait
  } else if (error instanceof FactuareaError) {
    console.error(error.code, error.requestId);
  }
}

Your API key is never included in any error message, stack or property — only the request_id (safe to log and share with support).

Webhooks

Verify the signature of an incoming webhook and get the typed event back. Pass the raw request body (a string), not a re‑serialized object:

import { Factuarea, WebhookSignatureError, SIGNATURE_HEADER } from "@factuarea/sdk";

const factuarea = new Factuarea({ apiKey: process.env.FACTUAREA_API_KEY! });

// Express, with express.raw({ type: "application/json" }) on the route:
app.post("/webhooks/factuarea", (req, res) => {
  try {
    const event = factuarea.webhooks.verify(
      req.body.toString("utf8"),
      req.headers[SIGNATURE_HEADER.toLowerCase()] as string,
      process.env.FACTUAREA_WEBHOOK_SECRET!,
    );
    // event is typed by its `type`
    if (event.type === "invoice.paid") { /* … */ }
    res.sendStatus(200);
  } catch (e) {
    if (e instanceof WebhookSignatureError) return res.sendStatus(400);
    throw e;
  }
});

Verification uses HMAC‑SHA256 with a constant‑time comparison and a configurable timestamp tolerance (default 5 minutes) to reject replays. It also accepts both signatures during a secret‑rotation grace window.

Binary downloads

PDF and other binary endpoints return a BinaryResponse (not JSON):

const pdf = await factuarea.invoices.pdf(invoiceId);
pdf.contentType;     // "application/pdf"
pdf.toBuffer();      // Node Buffer
pdf.toBlob();        // Blob (type preserved)
pdf.body;            // raw ArrayBuffer

Examples

Runnable examples live in examples/:

• create-invoice.ts
• list-invoices.ts
• download-pdf.ts
• verify-webhook.ts

Supported runtimes & deprecation policy

| Runtime | Status | | -------------------- | ------------------------------ | | Node 20 | ✅ supported (CI) | | Node 22 (LTS) | ✅ supported (CI, recommended) | | Node 24 | ✅ supported (CI) | | Deno / Bun / Workers | ✅ works (Web fetch based) |

Minimum Node 20. The full support matrix, the Node-version policy and the deprecation / breaking-change policy live in SUPPORT.md.

Versioning

This SDK follows SemVer and is aligned with the API's date-based Factuarea-Version. Each release pins one Factuarea-Version and sends it on every request, so the API's behaviour is stable until you upgrade the SDK — upgrading is how you adopt a newer API version. The pinned value per release is recorded in the CHANGELOG, and the full policy + version mapping is in docs/VERSIONING.md. While in 0.x, minor versions may include breaking changes.

Releases & spec sync

Releases are automated with Changesets and published to npm via Trusted Publishing (OIDC) with build provenance — see docs/RELEASING.md. The generated layer is kept in sync with the public OpenAPI spec automatically — see docs/SPEC_SYNC.md.

Contributing & spec

The typed surface in src/generated/ is generated from the OpenAPI spec; the hand‑written runtime lives in src/core/. The pinned spec is committed at spec/openapi.json (frozen against the private spec at commit e822661bc). Do not edit src/generated/ by hand — run npm run generate.

License

MIT © Factuarea