Edit API
Fill any PDF form from your data
Form field detection finds every fillable field in a PDF, then fills it from plain-language instructions or a schema and returns the edited file.
What it does
Instructions or schema
Describe what to fill in plain language, or pass a schema for repeatable, field-by-field control.
Every field type
Text, checkbox, radio, dropdown, option list, signature, and table fields. Flatten the PDF to lock filled values.
Edited file and values
The response returns the edited PDF and the values filled, and saved templates reuse a detected layout.
Under the hood
Detect form fields and fill them programatically.
Comprehensive field support
Detect and fill in checkboxes, signatures, text fields, tables, dropdowns, multi-line paragraphs, and character-per-box inputs (like SSNs).
Dynamic form filling for agents
Use natural language instructions to map data to the right fields automatically, no template required.
Template-based filling
For static forms, detect field positions once and fill them at scale deterministically.
Reliability at any scale
Fast, reliable results even on complex forms with hundreds of fields.
How to get started
Create an account
Sign up at dashboard.extend.ai. New accounts get 10,000 free credits.
Copy an API key from the Developers page and export it as EXTEND_API_KEY.
Choose how to call Edit
Studio: try Edit in the browser with no code.
MCP: connect Claude, Cursor, or any MCP client to https://mcp.extend.ai/mcp.
CLI: install with curl -fsSL https://extend.ai/install.sh | sh, then run extend setup.
SDKs: pip install extend-ai or npm install extend-ai; Java and Go SDKs are also available.
Process your first document
Send a blank PDF form and instructions; the response links to the filled file.
curl -X POST https://api.extend.ai/edit \ -H "Authorization: Bearer $EXTEND_API_KEY" \ -H "x-extend-api-version: 2026-02-09" \ -H "Content-Type: application/json" \ -d '{ "file": { "url": "https://extend-public-files.s3.us-east-2.amazonaws.com/f1040.pdf" }, "config": { "instructions": "Fill the form with the provided data." } }'Move to production
Send production traffic to POST /edit_runs; the synchronous POST /edit times out after 5 minutes.
Pricing
From 1 credit per page for filling, plus 2 for form detection when you skip the schema.
See full pricingUse cases
- Edit quickstart (Form 1040)
Tax forms
Fill IRS forms such as the 1040 from structured data or instructions.
- Workflows docs
Parse, extract, then fill
Move values from one document into another form in a single pipeline.
- Healthcare
Prior authorizations
Complete payer prior-auth forms from patient and clinical data.
- Financial services
Onboarding & account opening
Pre-fill account-opening applications from data you already hold.
- Edit docs
Static templates at scale
Detect field positions once, then fill the same form deterministically.
- Edit launch post
Agent-driven filling
Let an agent map data to fields with plain-language instructions.
