---
site_search: "GET /ask?q={query} (read-only search over extend.ai and docs.extend.ai; returns links and quoted passages, not generated answers)"
title: "Edit API: Detect and Fill PDF Form Fields | Extend"
description: "Detect and fill PDF form fields from plain-language instructions or a JSON schema. Text, checkbox, radio, dropdown, signature, and table fields, with optional flattening."
canonical: https://www.extend.ai/edit
---

# Edit API: Detect and Fill PDF Form Fields | Extend

> Search this site and the docs: [`/ask?q=…`](/ask?q=webhook+retries) returns matching pages from extend.ai and docs.extend.ai, with quoted passages.

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.

[Try for free](https://dashboard.extend.ai/) · [Book a demo](https://www.extend.ai/get-started)

## 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

### 1. 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.

[Sign up](https://dashboard.extend.ai/) · [Developers page](https://dashboard.extend.ai/developers)

### 2. 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.

[Open Studio](https://dashboard.extend.ai/studio) · [MCP setup](https://www.extend.ai/agents/mcp.md) · [CLI setup](https://www.extend.ai/agents/cli.md) · [SDK docs](https://docs.extend.ai/sdks)

### 3. Process your first document

Send a blank PDF form and instructions; the response links to the filled file.

```bash
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." } }'
```

### 4. Move to production

Send production traffic to POST /edit_runs; the synchronous POST /edit times out after 5 minutes.

[Edit File API reference](https://docs.extend.ai/api-reference/endpoints/edit/edit-file)

## Pricing

From 1 credit per page for filling, plus 2 for form detection when you skip the schema.

[See full pricing](https://www.extend.ai/pricing.md)

## Documentation

- [Editing overview](https://docs.extend.ai/editing/overview)
- [Edit File API reference](https://docs.extend.ai/api-reference/endpoints/edit/edit-file)
- [Evaluation overview](https://docs.extend.ai/evaluation/overview)

## Related reading

- [Introducing Edit with improved PDF form detection and filling](https://www.extend.ai/resources/introducing-edit-upgrade.md)
- [Introducing Edit](https://www.extend.ai/resources/introducing-edit-a-single-api-to-fill-any-form-programmatically.md)

## Use cases

### Tax forms

Fill IRS forms such as the 1040 from structured data or instructions.

[Edit quickstart (Form 1040)](https://docs.extend.ai/editing/overview)

### Parse, extract, then fill

Move values from one document into another form in a single pipeline.

[Workflows docs](https://docs.extend.ai/workflows/overview)

### Prior authorizations

Complete payer prior-auth forms from patient and clinical data.

[Healthcare](https://www.extend.ai/healthcare.md)

### Onboarding & account opening

Pre-fill account-opening applications from data you already hold.

[Financial services](https://www.extend.ai/financial-services.md)

### Static templates at scale

Detect field positions once, then fill the same form deterministically.

[Edit docs](https://docs.extend.ai/editing/overview)

### Agent-driven filling

Let an agent map data to fields with plain-language instructions.

[Edit launch post](https://www.extend.ai/resources/introducing-edit-upgrade.md)

## More products

- [Parse](https://www.extend.ai/parse.md)
- [Extract](https://www.extend.ai/extract.md)
- [Split](https://www.extend.ai/split.md)
- [Verify](https://www.extend.ai/verify.md)
- [Classify](https://www.extend.ai/classify.md)