Developer API

E-Signature API Built
for Developers

Integrate legally binding electronic signatures into any application in minutes, not months. A modern REST API with API-key auth on every plan from $12/mo, plus webhooks and embeddable signing from $29/mo.

See the Code

API access included with every plan. 7-day free trial, no credit card required.

Send a Document for Signature in Two API Calls

A clean, predictable API that does exactly what you expect. No XML. No SOAP. Just JSON.

Request — POST /api/documents, then POST /api/documents/:id/send
# 1. Upload the document (PDF, DOC, or DOCX)
curl -X POST https://shocksign.com/api/documents \
  -H "X-API-Key: YOUR_API_KEY" \
  -F "file=@contract.pdf" \
  -F "title=Service Agreement"

# 2. Send it for signature
curl -X POST https://shocksign.com/api/documents/DOCUMENT_ID/send \
  -H "X-API-Key: YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "signers": [
      { "name": "Jane Smith", "email": "jane@example.com", "order": 1 }
    ],
    "message": "Hi Jane, please review and sign."
  }'
Response — 200 OK
{
  "message": "Document sent for signature",
  "signatureRequests": [
    {
      "id": "b1c2d3e4-5f67-4890-a1b2-c3d4e5f60718",
      "signerEmail": "jane@example.com",
      "signerName": "Jane Smith",
      "signingUrl": "https://shocksign.com/sign/SIGNING_TOKEN",
      "order": 1
    }
  ],
  "ccRecipients": []
}

// Webhook events: document.created, document.sent, document.viewed,
// document.signed, document.completed, document.declined

Why Developers Choose ShockSign's API

Built by developers, for developers. Every design decision optimized for developer experience.

RESTful Design

Clean, predictable endpoints following REST conventions. JSON in, JSON out. No SOAP, no XML, no legacy baggage.

Webhooks & Events

Real-time notifications for every signature event. Document opened, signed, completed, declined — all delivered instantly.

API Key Auth

Simple, secure authentication with an X-API-Key header. Create, name, and revoke keys from your dashboard. OAuth 2.0 partner integrations available on request.

Embeddable Signing

Embed the signing experience directly in your app with a simple iframe. Fully white-labeled, fully customizable.

Signed Webhooks

Every webhook is signed with HMAC-SHA256 (X-ShockSign-Signature) and timestamped, so you can verify payloads before acting on them.

Straightforward Docs

A plain REST + JSON API you can call from any language with any HTTP client. Copy-paste curl samples for every endpoint — no client library required.

API vs Competitors

See how ShockSign's electronic signature API stacks up against DocuSign and HelloSign for developers.

FeatureShockSignDocuSignHelloSign
API Access Tier
Every plan — from $12/mo
Enterprise only
Business — $49/mo
Setup Time
Minutes
Days to weeks
Hours
Webhook Support
Yes
Yes
Yes
Embed Signing (iframe)
Yes
Yes
No
Rate Limits
Fair-use limits; higher on request
Varies by contract
100 req/min
Free Trial API Access
7-day trial, no card
Developer account
Test mode
Client Libraries
Any HTTP client (REST + JSON)
6+ languages
3 languages
Transparent Pricing
Yes
No
Yes

Integration Examples

From embedded signing to fully automated document pipelines — build anything with the ShockSign API.

Web App Integration

Embed the full signing experience inside your SaaS product. Your users sign documents without ever leaving your application. White-label ready with custom branding.

CRM Automation

Trigger signature requests directly from your CRM pipeline. When a deal moves to "Contract Sent," ShockSign sends the document automatically. Works with any CRM via webhooks or Zapier.

Document Workflow

Build automated contract pipelines — generate documents from templates, route them for sequential or parallel signing, archive completed files, and notify stakeholders at every step.

Start Building with ShockSign API

Get your API key and send your first document for signature in under 5 minutes. API access included with every plan.

7-day free trial. No credit card required to start.