MatterReady™ Sign API · Coming soon

An eSignature API with sealed, timestamped PDFs

Built for legal software and any document that has to hold up years later. Send documents for signature from your application, follow each envelope by webhook, and get back a digitally sealed, timestamped PDF with the audit trail inside it. $99/month for 200 envelopes, API included, no per-seat fees.

Join the early-access list See eSignature API pricing

How it works

From PDF to sealed document

Create an envelope

Point to your PDF by HTTPS URL with its SHA-256 hash, list the signers, and place signature, initials, date, text, and checkbox fields by page and position. Pre-fill any values you already know.

Signers are emailed a private link

Each signer opens the document in the browser, with no account, and consents to sign electronically before drawing, typing, or uploading a signature. With a signing order set, each person is emailed when it is their turn.

Track status by webhook or API

Receive a webhook when an envelope is sent, completed, sealed, declined, voided, or expired, or fetch its status at any time. Send a reminder or void an envelope with one call.

Download the sealed PDF and evidence

The completed document is sealed with an Adobe-trusted certificate and an RFC 3161 timestamp, with a completion certificate appended. The machine-readable audit trail is available separately.

Example

Create an envelope with two signers in order

A simplified request. Early-access developers get the full request schema with their sandbox key.

curl -X POST https://sign.matterready.io/api/v1/envelopes \
  -H "Authorization: Bearer mrs_test_..." \
  -H "Content-Type: application/json" \
  -d '{
    "name": "Services agreement",
    "source_pdf_url": "https://files.example.com/agreement.pdf",
    "source_pdf_hash": "<sha-256 of the PDF>",
    "apply_signing_order": true,
    "recipients": [
      { "role": "client",  "name": "Jordan Smith", "email": "jordan@example.com", "signing_order": 1 },
      { "role": "company", "name": "Alex Lee",     "email": "alex@example.com",   "signing_order": 2 }
    ],
    "fields": [
      { "recipient_role": "client",  "type": "signature", "page": 3, "x": 0.12, "y": 0.78, "width": 0.33, "height": 0.05 },
      { "recipient_role": "client",  "type": "date",      "page": 3, "x": 0.52, "y": 0.78, "width": 0.20, "height": 0.03 },
      { "recipient_role": "company", "type": "signature", "page": 3, "x": 0.12, "y": 0.87, "width": 0.33, "height": 0.05 }
    ]
  }'

Endpoints

What the API covers

Endpoint	What it does
`POST /api/v1/envelopes`	Create and send an envelope: document, signers, fields, signing order, expiry, branding
`GET /api/v1/envelopes/:id`	Envelope status with each signer's progress
`POST /api/v1/envelopes/:id/remind`	Re-send the signing email to signers who haven't finished
`POST /api/v1/envelopes/:id/void`	Cancel an envelope that is still out for signature
`GET /api/v1/envelopes/:id/sealed-pdf`	Download the sealed, signed PDF
`GET /api/v1/envelopes/:id/evidence`	Download the envelope's audit trail as JSON
`GET /api/v1/envelopes/:id/verify-pdf`	Re-verify a sealed PDF's signature, timestamp, and integrity

Evidence

An audit trail you can check

Every event in an envelope's life (created, sent, viewed, signed, declined, completed, sealed) is written to a hash-chained log, where each entry includes the hash of the one before it. Editing or removing an event breaks the chain. The chain root is printed on the completion certificate, and any sealed document can be checked on MatterReady's public verification page.

Keys and environments

Separate sandbox and production keys

Keys are scoped to your account and to one mode, sandbox or live, stored only as hashes, and revocable. Sandbox envelopes go through the whole signing flow but are watermarked, never sealed, never billed, and can only be sent to addresses on your own domains, so a test can't reach a real customer.

eSignature API questions

How much does the MatterReady Sign API cost?

$99 per month for 200 envelopes, with full API access included and no per-seat fees (planned launch pricing). Sandbox keys for development will be free.

When can I get API keys?

MatterReady Sign is coming soon. Join the early-access list and we'll send you a sandbox key and walk you through the integration as access opens.

How do I send the document to be signed?

Host the PDF at an HTTPS URL and include its SHA-256 hash when you create the envelope. The hash lets MatterReady Sign confirm it is sealing exactly the file you sent.

How are signature fields positioned?

Each field is placed by page number and a position given as fractions of the page (x, y, width, height from 0 to 1, measured from the top-left corner), so it works at any page size. Each field is assigned to a signer role. Text-tag placement inside the document isn't supported.

Can I test without sending real signature requests?

Yes. Sandbox keys run the full signing flow, but documents are watermarked, never sealed, never billed, and can only be sent to email addresses on your own domains.

Building legal software?

MatterReady Sign comes from a legal intake platform and handles the documents law firms send most: engagement agreements, authorizations, and intake forms. See the legal document signing use cases.

Join the early-access list MatterReady Sign overview