For developers · REST API

A digital signature API for your system

Upload a document, invite the signers and pull the signed file back into your system. Signers use Smart-ID, Mobile-ID, an ID card or another EU country's eID — you do not build the signing yourself.

Create an account and API key See the price API documentation

Legally equal to a handwritten signature in every EU country (eIDAS QES).

Qualified signatures in your system, with no eID integration of your own.

Documents

Upload a PDF or an ASiC-E container as multipart — no base64 field and no small size ceiling. Check the status, then download the signed file or the original.

Signers

Add a signer by e-mail — they get a link — or by personal code and country, which puts the request in their 1DOX inbox with no e-mail at all. If you send invitations yourself, the API returns the signing link.

Send a reminder, remove a signer or cancel every outstanding request.

Webhooks

1DOX notifies your address when a signature is added, the document is complete or a signer declines. Each delivery is signed with HMAC-SHA256 and a failed one is retried up to 5 times. No polling needed.

Qualified signatures

The signer signs on the 1DOX page with their eID. The result is a qualified electronic signature (QES) under eIDAS, valid across the European Union.

Keys per workspace

An API key belongs to one workspace and sees only its documents. Each workspace can have up to three keys — give every integration its own.

OpenAPI documentation

Every call and the webhook body are described in an OpenAPI 3.1 specification. Errors come as RFC 9457 problem details.

How to start

Step 1

Create an account

Create a 1DOX account and pick your personal or company workspace.

Step 2

Create an API key

Under Settings → API, create a key and add your webhook address.

Step 3

Send a document

Upload a document, add the signers and wait for the webhook that says it is complete.

Price

The API costs nothing extra: every plan gets API keys, the free one included. A signature costs the same as in the portal — €0.36 for a standard signature, €6 for an international remote QES — paid by the document owner. Every new account gets €5 of free signing credit.

Signature costs · Pay-as-you-go

€0.36/ standard signature

Smart-ID, Mobile-ID, ID-card

Premium QES: €6e.g. ADACOM remote QES for international signers without local eIDs

Claim €5 free credit

Frequently asked questions

Do I have to integrate Smart-ID or the ID card myself?

No. Signing happens on the 1DOX signing page, which offers Smart-ID, Mobile-ID, ID cards and other EU countries' eIDs. Your system sends the document and gets the signed file back.

Does the signer need a 1DOX account?

Not with an e-mail invitation: they open the link and sign. An identity-bound request lands in their 1DOX inbox, which they open by logging in with their eID.

How do I verify a webhook?

Compute HMAC-SHA256 over the raw request body with your workspace's webhook secret and compare it with the x-1dox-signature header. Retries carry the same deliveryId, so you can skip a delivery you already handled.

Do plan limits apply to the API?

Yes. A document uploaded through the API passes the same checks as one uploaded in the portal: the document count and file size follow the workspace's plan.

Where is the API documentation?

At 1dox.eu/docs/api. The machine-readable OpenAPI specification is at 1dox.eu/api/v1/openapi.json.

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eIDAS qualified signaturesGDPR compliantDocuments stored in the EU