I Built an API That Parses Any Contract into Structured JSON

Sebastian Snow — Mon, 18 May 2026 09:40:14 +0000

I Built an API That Parses Any Contract into Structured JSON

Every company deals with contracts. NDAs, employment agreements, leases, SaaS terms — they all contain critical data buried in unstructured text. Extracting that data manually is slow, expensive, and error-prone.

So I built Clausify — an API that takes any contract document and returns clean, structured JSON with all the key fields extracted.

What It Does

Upload a contract (PDF, Word, scanned image, or text file), and Clausify returns structured data like this:

{
  "parties": [
    {
      "name": "Acme Corporation",
      "address": "123 Business Ave, New York, NY",
      "representative": "John Smith, CEO"
    },
    {
      "name": "Beta Technologies LLC",
      "address": "456 Tech Road, San Francisco, CA",
      "representative": "Jane Doe, CTO"
    }
  ],
  "effective_date": "2024-01-15",
  "duration": "3 years",
  "obligations_of_receiving_party": "Shall not disclose any Confidential Information to third parties without prior written consent.",
  "governing_law": "State of New York"
}

One API call. No ML pipeline to set up. No training data needed.

How to Use It

1. Get Your API Key

2. Parse a Contract

cURL:

curl -X POST "https://clausify.p.rapidapi.com/v1/extractions" \
  -H "X-RapidAPI-Key: YOUR_API_KEY" \
  -H "X-RapidAPI-Host: clausify.p.rapidapi.com" \
  -F "file=@contract.pdf" \
  -F "contract_type=nda"

Python:

import requests

url = "https://clausify.p.rapidapi.com/v1/extractions"
headers = {
    "X-RapidAPI-Key": "YOUR_API_KEY",
    "X-RapidAPI-Host": "clausify.p.rapidapi.com"
}

with open("contract.pdf", "rb") as f:
    response = requests.post(
        url,
        headers=headers,
        files={"file": f},
        data={"contract_type": "nda"}
    )

data = response.json()
print(data["result"])

JavaScript:

const form = new FormData();
form.append("file", fs.createReadStream("contract.pdf"));
form.append("contract_type", "nda");

const response = await fetch(
  "https://clausify.p.rapidapi.com/v1/extractions",
  {
    method: "POST",
    headers: {
      "X-RapidAPI-Key": "YOUR_API_KEY",
      "X-RapidAPI-Host": "clausify.p.rapidapi.com",
    },
    body: form,
  }
);

const data = await response.json();
console.log(data.result);

3. Choose Your Contract Type

Clausify has 6 built-in templates optimized for different contract types:

Type	What It Extracts
`general`	Parties, dates, obligations, price, terms
`nda`	Confidential info definition, duration, exclusions
`employment`	Salary, benefits, probation, non-compete
`lease`	Rent, deposit, maintenance, renewal terms
`saas`	SLA, data handling, liability, auto-renewal
`procurement`	Goods, quantity, delivery, warranty, penalties

Or pass custom fields to extract exactly what you need:

-F 'fields=["vendor_name", "payment_deadline", "penalty_clause"]'

Use Cases

Legal Tech Platforms — Auto-populate case management systems with contract data.

HR Software — Parse employment contracts to extract salary, benefits, and start dates.

Real Estate Tools — Extract lease terms, rent amounts, and renewal dates from rental agreements.

Procurement Systems — Pull vendor info, pricing, and delivery dates from purchase orders.

Due Diligence — Batch-process hundreds of contracts during M&A and extract key terms.

How I Built It

The tech stack is straightforward:

FastAPI for the API framework
GPT for intelligent extraction (not regex — it understands context)
PyMuPDF for PDF text extraction
python-docx for Word documents
GPT Vision for scanned documents (built-in OCR)
Railway for deployment
RapidAPI for distribution and billing

The core logic is simple: parse the document into text, send it to GPT with a contract-type-specific prompt, and return structured JSON. The magic is in the prompt engineering — each contract type has an optimized extraction template.

Pricing

Plan	Price	Requests
Basic	Free	20/month
Pro	$9.99/mo	200/month
Ultra	$29.99/mo	800/month
Mega	$69.99/mo	3000/month

Try It

The free tier gives you 20 requests to test with your own contracts:

Try Clausify on RapidAPI →

I'd love to hear your feedback — what contract types or features would be most useful for your workflow? Drop a comment below.

DEV Community: Sebastian Snow

I Built an API That Parses Any Contract into Structured JSON

I Built an API That Parses Any Contract into Structured JSON

What It Does

How to Use It

1. Get Your API Key

2. Parse a Contract

3. Choose Your Contract Type

Use Cases

How I Built It

Pricing

Try It