Documentation

Everything you need to integrate blocksign.red into your application.

Quick start

Create your first envelope and collect signatures in under 5 minutes.

API reference

RESTful API with OpenAPI spec. Authentication, envelopes, signers, webhooks.

Verification

How blockchain anchoring works and how to independently verify any signature.

Document preparation

Upload a PDF, visually place signature fields, assign signers, and send — all from the browser.

Compliance

eIDAS, ESIGN, UETA, HIPAA, SOC 2 — what each standard requires and how we meet it.

Quick start

Get up and running in minutes. Sign up for an account, grab your API key from the dashboard, and send your first envelope using the endpoint below. Add signers, upload a PDF, and blocksign.red handles the rest — email notifications, the signing ceremony, audit trail, and blockchain anchoring are all automatic.

API base URL

https://api.blocksign.red/v1

Authentication

All API requests require a Bearer token in the Authorization header.

Authorization: Bearer <your-api-key>

Create an envelope

POST /v1/envelopes
Content-Type: application/json

{
  "document_id": "<document-id-from-upload>",
  "title": "NDA — Acme Corp",
  "routing_mode": "sequential",
  "signers": [
    {
      "client_ref": "signer1",
      "email": "alice@example.com",
      "name": "Alice",
      "routing_order": 1
    }
  ],
  "fields": [
    {
      "signer_ref": "signer1",
      "page": 1,
      "x": 0.1, "y": 0.2,
      "w": 0.3, "h": 0.05,
      "field_type": "signature",
      "required": true
    }
  ]
}

Webhooks

Subscribe to real-time events: envelope.completed, signer.signed, envelope.anchored. All webhook payloads include an HMAC signature for verification.

Document preparation

The /prepare page lets you create envelopes entirely from the browser — no API integration required.

  1. Upload — drag-and-drop or browse for a PDF (up to 25 MB). The document is stored server-side and a preview renders immediately.
  2. Place fields — select a field type (Signature, Initials, Text, Date, Checkbox) from the toolbar, then click on a page to drop it. Drag to reposition, resize from the bottom-right handle, and use the popover to assign the field to a signer, toggle required, or set a label.
  3. Review & send — add signer names and emails, choose sequential or parallel routing, review the field count per signer, and hit Send. Each signer receives an email with a unique signing link.

Under the hood, the prepare UI calls the same POST /v1/documents, POST /v1/envelopes, and POST /v1/envelopes/:id/send endpoints documented below — so everything is available programmatically too.

Field coordinate system

All field positions use normalized coordinates in the range [0, 1] relative to the page dimensions. The origin is at the bottom-left corner (PDF user space convention). For example, x: 0.1, y: 0.5, w: 0.3, h: 0.05 places a field starting 10% from the left edge and 50% up from the bottom, spanning 30% of the page width and 5% of its height.

Verification

Every signing event is SHA-256 hashed into a per-envelope hash chain. Each hash covers the previous hash at the envelope level and at the trigger level, so changing any event is detectable. We independently recompute the chain tip on every verification request; if it diverges from what's stored we surface it as a break. The Merkle root of those tips is also published to two public blockchains (Bitcoin via OpenTimestamps and Base L2), so the integrity claim doesn't rest on us alone. Anyone with an envelope ID can verify at /verify — no account required.

Compliance

blocksign.red is designed to meet the requirements of major electronic-signature and data-protection standards. Supported and roadmap frameworks include:

  • ESIGN Act & UETA (United States)
  • eIDAS SES / AES / QES (European Union)
  • HIPAA (healthcare)
  • 21 CFR Part 11 (life sciences)
  • SOC 2 Type II
  • GDPR
  • PAdES-LTV (long-term validation PDF signatures)

Data resides in your region by default.