E-invoicing API in 2026: what to look for (and how Docnova compares)

Picking the wrong e-invoicing API in 2026 is an expensive mistake. Compliance mandates have expanded to Poland (KSeF), Romania (ANAF), France (PPF), Malaysia (LHDN), Belgium, Denmark, and more and the pace is accelerating. A single-country wrapper that served you in 2023 will not survive the next three years. This guide walks through what a production-grade e-invoicing API must deliver today, then shows exactly how Docnova’s API stacks up against each criterion.

What to Look for in an E-Invoicing API

The first question is scope: does the API treat every country as a first-class citizen, or does it bolt on new markets as an afterthought? Look for country-specific submission endpoints rather than a generic “send invoice” call that silently ignores local format requirements. You also need clear versioning, predictable error codes aligned with each tax authority’s own error vocabulary, and a sandbox environment that mirrors production behavior closely enough to trust your test results. Finally, check whether the provider maintains the compliance logic format changes, new certificate requirements, authority downtime handling or whether that burden falls on your team.

Authentication and Security

JWT-based authentication is the baseline in 2026. Beyond login and token refresh, a mature API exposes API key management so that server-to-server integrations never touch user credentials. Docnova’s API key system, accessible under ERP Management settings, lets teams generate named keys with explicit expiry dates each key is shown in full only at generation time and masked in all subsequent views. Individual keys can be enabled or disabled via an ACTIVE toggle without revoking the entire integration, which is essential for credential rotation in production. The standard auth flow uses POST /auth/login for JWT issuance and POST /auth/refresh for token renewal; API keys follow the same JWT scheme for ERP and system integrations.

Multi-Country Support

A credible e-invoicing API in 2026 covers at minimum the markets where your customers operate today and the ones where mandates are coming next. Docnova exposes country-specific submission endpoints for Poland (POST /invoice/PL → KSeF), Romania (POST /invoice/RO → ANAF), France (POST /invoice/FR → PPF), Malaysia (POST /invoice/MY → LHDN), Denmark (POST /invoice/DK → NemHandel), Belgium (POST /invoice/BE), Croatia (POST /invoice/HR), Sweden (POST /invoice/SE), Serbia (POST /waybill/RS), and Egypt (POST /egypt-invoice → ETA). Each country path also includes the corresponding certificate and session-token endpoints so that the full auth handshake with each tax authority is handled server-side. The Peppol network is supported separately via POST /peppol/register and GET /peppol for cross-border document exchange.

API Works

Webhook and Event Support

TODO: verify: webhook/event push endpoints no webhook-specific endpoints were found in the API catalog source. Verify from backend controllers before publishing.

Real-time event delivery matters for invoice workflows: your ERP should know the moment a submission succeeds or a tax authority returns a rejection, without polling. When evaluating an e-invoicing API, confirm it offers outbound webhook delivery for at minimum submission status changes, authority acknowledgements, and payment events. Check whether retries are automatic on delivery failure and whether the event payload includes the authority’s own reference ID for reconciliation. Docnova’s API includes POST /invoice/payment for recording payment events and per-country token endpoints that manage authority session state; for webhook push configuration specifics, consult the Docnova developer documentation or contact the integration team.

How Docnova’s API Works

Docnova’s REST API follows resource-oriented design throughout. CRUD operations live at /{resource} (e.g., GET /invoice, POST /invoice, PUT /invoice/{id}), country-specific submissions extend the same resource with a country code suffix (/invoice/PL, /invoice/RO), and sub-resources use the /{resource}/{id}/{sub-resource} pattern. All endpoints except paths under /public/** and /auth/** require a valid JWT in the Authorization header.

The API key management interface in ERP Management settings maps directly to these integrations: each Company-type API key authorises a connected ERP or external system to act on behalf of that company. Keys carry an expiry date one-year validity is typical and can be deactivated individually. The partner directory endpoints (/partner/*) and business partner network endpoints (/business-partner/*) are available for building supplier or customer-facing integrations on top of the invoicing core.

Conclusion

An e-invoicing API worth building on in 2026 needs JWT plus API key auth, per-country submission endpoints backed by real authority integrations, and a clear path to the markets you will need next year. Docnova covers all of those with a documented REST API, named API key management with expiry and toggle controls, and country-specific endpoints spanning ten jurisdictions today. Try Docnova free or book a demo at docnova.ai.