REST API · AcroForm · Overlay

Fill any
PDF form
via API.

Upload any PDF with form fields. Get it back filled — in milliseconds. AcroForm detection, overlay support, checkbox & radio handling. No SDKs. Just REST.

Start for free View Docs →
2
Endpoints
<1s
Avg. response
99%
Field accuracy
example — POST /fill
# Step 1: Analyze your PDF POST https://api.ops-os.ai/analyze Content-Type: multipart/form-data X-API-Key: your_api_key ← Response: { "document_id": "doc_a1b2c3", "has_acroform": true, "fields": [{ "field_name": "FirstName" }] } # Step 2: Fill it POST https://api.ops-os.ai/fill { "document_id": "doc_a1b2c3", "fields": [{ "field_name": "FirstName", "value": "Maria" }] } ← Get back your filled PDF ✓
Simple by design

Two endpoints.
Infinite forms.

Step 01
🔍
Analyze

Upload any PDF. The API detects all form fields, their types (text, checkbox, radio, date), positions, and the best fill strategy.

POST /analyze
Step 02
✍️
Fill

Send field values using the document_id from step 1. Works with AcroForm fields or coordinate-based overlay — auto-detected.

POST /fill
Step 03
📄
Download

Get back a perfectly filled PDF. Print it, send it, or store it. Pixel-perfect output every time.

GET /download/{id}
Built for builders

Who uses
FormFlow?

⚖️
Law Firms & Legal Tech

Automate court documents, contracts, and applications. Fill hundreds of forms programmatically without touching a PDF editor.

→ Contracts · Court Docs · Applications
🏗️
Freelancers & Agencies

Your client needs PDF automation? Drop in the FormFlow API in hours. No PDF library wrestling. Clean REST, clean output.

→ n8n · Zapier · Custom Apps
🏛️
Government & NGOs

Social benefit forms, visa applications, permit requests. Support multiple users filling the same form template at scale.

→ Social Benefits · Permits · Registrations
🤖
AI & Automation Tools

Building an AI assistant that handles documents? FormFlow handles the PDF layer so you can focus on the intelligence layer.

→ Chatbots · Workflows · Document AI
No surprises

Transparent
pricing.

Free
€0
forever
20 requests / month
  • Analyze endpoint
  • Fill endpoint
  • AcroForm support
  • Community support
Get started
Most Popular
Starter
€19
per month
500 requests / month
  • Everything in Free
  • Overlay fill mode
  • Email support
  • 0.038€ per extra req
Get Starter
Pro
€49
per month
2,000 requests / month
  • Everything in Starter
  • Priority processing
  • Usage dashboard
  • 0.025€ per extra req
Get Pro
Pay-as-you-go
€0.05
per request
No monthly limit
  • No subscription
  • Pay only what you use
  • Perfect for sporadic use
  • Email support
Contact us
Also available on

Find us on
RapidAPI.

1
Search "FormFlow PDF"
Find the API on RapidAPI Marketplace. Thousands of developers discover APIs there daily.
2
Subscribe with one click
No account setup with us needed. Use your existing RapidAPI account and start immediately.
3
Test in the browser
RapidAPI has a built-in playground. Test /analyze and /fill directly — no Postman needed.
4
Copy code snippet
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Why RapidAPI?
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