A simple and documented REST API to add electronic signature to any software. Compatible with HelloCabAvocat, ERP, CRM and any web application.
Changing your management software to get integrated signing is costly and risky. Training your teams, migrating your data, modifying your processes — for a single feature.
You have to leave your business software, go to another platform, upload manually, come back to your tool. A tedious and error-prone process.
Migrating to a new all-in-one software to get signing costs dearly in time, money and training. Often disproportionate.
Building a signing system from scratch is very complex: OTP, PDF, evidence, eIDAS compliance. Months of development for uncertain results.
A simple, well-documented REST API with concrete examples. Keep your current software and add signing in less than a day of development.
Create your API key in one click from your HelloWeSign dashboard. Set a name, monthly quota and webhook URL. Your key is immediately operational.
Less than 2 minutes to be readySend your PDF in base64 with the list of signers, callback URL and metadata. HelloWeSign creates the request, stores the file and generates signing links.
A single POST request to start everythingEach signer automatically receives their invitation email with a unique link. They view the document, verify via OTP, sign — without creating an account.
100% autonomous signer experienceAs soon as everyone has signed, HelloWeSign calls your webhook URL with the status and download links for the signed document and evidence file. Your system updates automatically.
HMAC signature to verify webhook authenticityPOST /api/v1/signature-requests
Authorization: Bearer votre_cle_api
{
"document": "base64...",
"filename": "contrat.pdf",
"signers": [
{
"name": "Jean Dupont",
"email": "jean@mail.com",
"order": 1
}
],
"callbackUrl": "https://votre-app.com/webhook",
"externalReference": "DOSSIER-2024-001"
}// Response: unique signing link per signer + request ID
Everything you need for a professional and reliable integration.
Standard JSON/REST interface, compatible with all languages and frameworks. OpenAPI documentation available.
Secure API keys via Authorization header. Monthly quota management per key to control usage.
Automatic notification of your endpoint on each status change. HMAC-SHA256 signature for security.
Send your PDF directly in the API request as base64. No need to handle a separate file upload.
Each signer receives a unique and secure URL. Single-use token, configurable expiration.
Designed to work natively with HelloCabAvocat. Send documents for signing directly from your client files.
Any software publisher or developer who wants to add electronic signature without starting from scratch.
Sending a document for signing directly from the client file.
The lawyer clicks 'Send for signature' in HelloCabAvocat. The HelloWeSign API handles everything. The status updates automatically in the file.
Automating sales contracts from a commercial CRM.
As soon as an opportunity moves to 'Won', the CRM calls the API to send the contract. Signature obtained without leaving the sales process.
Adding signing to an online property management platform.
Leases are signed directly from the platform. No redirection to a third-party tool. 100% integrated experience for tenants.
Standard REST API with clear documentation. An experienced developer can integrate complete signing in half a day.
Complete documentation with request and response examples for each endpoint. Examples in JavaScript, Python, PHP.
HelloWeSign manages the entire signer interface (invitation, OTP, signature, confirmation). You only need to handle the result webhook.
From sending the document to receiving the signed version, everything is automated. Your application is notified automatically via webhook.
Webhooks include a verifiable HMAC-SHA256 signature. You can be certain of the authenticity of received notifications.
Plans adapted to your volume, from 5 signatures/month (FREE) to unlimited (ENTERPRISE). Predictable billing.
Create your account, generate your API key and start integrating in hours. Documentation and examples included.