The E-Signature API for Your Own App
Send documents for legally binding electronic signature straight from your software. Create them from templates, JSON or PDFs, get a webhook the moment they are signed and download the sealed PDF - with one simple REST API.
curl https://api.airsign.com.au/api/v1/SessionFromTemplate \
-H "Authorization: Bearer $AIRSIGN_TOKEN" \
-H "Content-Type: application/json" \
-d '{
"templateId": "7f3c...e21a",
"name": "Employment agreement - Jane Smith",
"recipients": [
{ "name": "Jane Smith", "email": "[email protected]" }
],
"variableValues": { "start_date": "3 November 2026" },
"sendImmediately": true
}'E-Signatures Built Into Your Workflow
Copying details into a signing app and chasing people by email does not scale. The AirSign e-signature API lets the systems you already use - your CRM, HR platform, practice software or website - send the right document to the right person automatically, and get the signed copy back without anyone lifting a finger.
Simple REST + JSON
Plain HTTPS requests from any language. No SDK to install and no XML.
No Separate API Plan
Included on every paid plan from $5 a month. API documents use your normal plan sessions.
Legally Binding
The same consent, sealed PDF and audit trail as signing from the AirSign website.
What You Can Build With the AirSign API
A few of the ways Australian businesses use the API to take the paperwork out of their day.
Employee onboarding
When a new starter is added to your HR or payroll system, send their contract, tax and super forms for signing automatically.
Contracts from your CRM
Mark a deal as won and the agreement goes out pre-filled with the customer's details, ready to sign on their phone.
Property and leasing
Generate leases, condition reports and authorities from your property platform and track who still has to sign.
Health and NDIS consent
Send consent forms and service agreements from your client system and file the signed copy against the right record.
Website sign-ups
Turn an online form into a signed agreement - your site calls the API and the customer signs in the same sitting.
High-volume sending
Send the same template to hundreds of people with their own details filled in, and follow progress from your own dashboard.
Everything You Need to Send and Track Signatures
Each feature links to its page in the developer documentation.
Send from templates
Build a template once in the AirSign editor, then send it with recipients and variable values in a single API call.
View docsDocuments from JSON
No PDF? Describe the document as headings, paragraphs, fields and signature blocks and AirSign lays it out for you.
View docsUpload your own PDFs
Upload an existing PDF and its form fields are imported automatically. Add signature fields by page position or next to printed text.
View docsDraft, review, then send
Sessions are created as drafts by default so someone can check them in AirSign first - or set sendImmediately to send straight away.
View docsWebhooks for every step
Get notified when a document is created, emailed, signed by each person, completed or declined, with automatic retries if your endpoint is down.
View docsDownload signed PDFs
Fetch the completed, sealed PDF and the certificate of completion with its audit trail, ready to store in your own system.
View docsTrack and manage sessions
List and filter sessions, check each recipient's status, resend invitations, update drafts and archive what you no longer need.
View docsSecure OAuth 2.0
Server-to-server access with the OAuth 2.0 client credentials flow. Create and revoke API clients any time from your settings.
View docsHow to Send a Document for Signature With the API
Create API credentials
In AirSign, open Settings > API and create a client. You get a client ID and secret for your server.
Get an access token
Exchange your credentials for a Bearer token with one call to the OAuth 2.0 token endpoint.
Send a document
Create a signing session from a template, a JSON document or an uploaded PDF, and choose whether to send it now.
Get the signed copy
A webhook tells you when it is signed. Download the sealed PDF and certificate and file them where they belong.
Start with the authentication guide, then send your first template.
API Endpoints at a Glance
All requests go to https://api.airsign.com.au/api/v1 with a Bearer token.
Sessions
E-Signature Webhooks
Instead of polling, let AirSign tell you what happened. Add an endpoint in Settings > Webhooks, pick the events you care about and AirSign sends a JSON POST each time one fires. Failed deliveries are retried automatically, and you can see every delivery and send a test event from the same screen. Read the webhooks setup guide for details.
session.createdsession.email_sentsession.file_filledsession.signature_appliedsession.recipient_completedsession.completedsession.declinedtemplate.createdtemplate.updateddocument.activateddocument.reneweddocument.expiring_soondocument.expireddocument.retiredtraining.invite_senttraining.completedform.invite_sentform.completedA Free E-Signature API on Every Paid Plan
No API surcharge
No developer tier and no per-call fees. Documents sent through the API use the sessions already in your plan.
Australian data storage
API documents are stored in Australian data centres, the same as everything else in AirSign.
Same legal standing
Every API signature carries the consent record, sealed PDF and certificate of completion.
Compare plans on the pricing page.
E-Signature API FAQs
An e-signature API lets your own software send documents for electronic signature without anyone logging in to a separate signing app. Your system creates the document and recipients with an API call, the signers get an email and sign on any device, and your system is told when it is done and can download the signed PDF.
API access is included at no extra cost on every paid AirSign plan, starting from the $5 a month Starter plan. There is no separate developer plan and no per-call fee. Documents sent through the API count toward your plan's monthly sessions exactly like documents sent from the website.
Yes. A document sent through the API goes through the same signing process as one sent from the AirSign website, with signer consent, a tamper-evident sealed PDF and a full audit trail. Electronic signatures are recognised under the Electronic Transactions Act 1999 (Cth) and the matching state and territory laws, with some exceptions such as certain deeds and documents that must be witnessed in a particular way.
No. You can send a template you built in AirSign, upload your own PDF, or describe the document in JSON using the block document format - headings, paragraphs, bullet lists, images, input fields and signature blocks - and AirSign lays out and places every field for you.
Any language that can make an HTTPS request - Node.js, Python, PHP, C#, Java, Go, Ruby and so on. The API is plain REST with JSON bodies and OAuth 2.0 Bearer tokens, so there is no SDK to install.
Add a webhook in Settings > Webhooks and AirSign will POST to your endpoint as things happen - when each recipient signs, when the whole document is completed or if someone declines. Failed deliveries are retried automatically. You can also poll the session endpoint for its status.
Yes. Sessions are created as drafts unless you set sendImmediately to true, so you can create, inspect and update documents freely and only send when you are ready. Start a free trial to get going.
Documents created through the API are stored in the same place as everything else in AirSign - Australian data centres, in line with the Australian Privacy Principles.
Yes. Use the Zapier integration to connect AirSign to thousands of apps, or connect ChatGPT or Claude through the AirSign MCP server and ask for what you need in plain English.
AirSign gives you the core signing workflow - templates, recipients, webhooks and signed PDF downloads - on every paid plan from $5 a month, with no separate API plan to buy. It is built for Australian businesses, with Australian data storage and local support.
Send your first document from code today
Start a free AirSign trial, create an API client in Settings and send a document for signature in a few minutes.