ICD-10 Codes — Free Medical Diagnosis Code Lookup API (No Key)

How to Use This API

1. Search for a Diagnosis Code

https://icd10api.com/?code=E11.9

Returns the full description and metadata for Type 2 diabetes without complications.

2. Search by Description

https://icd10api.com/?desc=hypertension

Returns all ICD-10 codes matching "hypertension".

3. Combined Search

https://icd10api.com/?desc=fracture&code=S52

4. JavaScript — Lookup Tool

async function lookupICD(code) {
  const resp = await fetch(`https://icd10api.com/?code=${code}`);
  const data = await resp.json();
  if (data.IsError === false) {
    console.log(`Code: ${data.Code}`);
    console.log(`Description: ${data.Description}`);
    console.log(`Valid: ${data.IsValid}`);
    console.log(`Billable: ${data.IsBillable}`);
  }
}

lookupICD('J45.0');  // Asthma

5. Python — Bulk Code Resolver

import requests

codes = ['I10', 'E11.9', 'J45.0', 'M54.5', 'N39.0']
for code in codes:
    resp = requests.get('https://icd10api.com/', params={'code': code})
    data = resp.json()
    if not data['IsError']:
        print(f"{data['Code']}: {data['Description']}")
    else:
        print(f"{code}: Not found")

TL;DR

ICD-10 Codes provides a simple REST API for looking up medical diagnosis codes from the ICD-10-CM (Clinical Modification) standard used in US healthcare. Search by code (e.g., E11.9) or by description text (e.g., hypertension). Each result includes the code, full description, valid status, and billable indicator. Perfect for medical billing software, EHR integration, healthcare education tools, and clinical reference apps. No API key needed — just query and get JSON.

Quick start: https://icd10api.com/?code=E11.9

No API key needed — just make a request!

Look up ICD-10 code E11.9: https://icd10api.com/?code=E11.9

Try This URL Now

Frequently Asked Questions

What is ICD-10-CM?: ICD-10-CM (Clinical Modification) is the US standard for diagnosis codes used in healthcare billing, medical records, and epidemiology. It replaces the older ICD-9 standard.
Do I need an API key?: No. This API is completely free and open. No registration or authentication required.
How many codes are available?: The database covers the complete ICD-10-CM code set — approximately 70,000+ diagnosis codes with their descriptions and metadata.
Is this suitable for production medical use?: This is a helpful reference tool, but always verify critical medical coding against official CMS/CDC sources. The API is best suited for educational and development purposes.
Can I search by partial code?: Yes, partial code searches work. Searching S52 returns all codes in the forearm fracture category.
What's the difference between Valid and Billable?: A valid code exists in the ICD-10-CM system. A billable code is specific enough to use on insurance claims for reimbursement. Some codes are valid but not billable (used as category headers).

API Details

API URL: https://icd10api.com/
Documentation: icd10api.com
Category: Health
Authentication: Not Required
Geographic Coverage: United States (ICD-10-CM standard)

What You Can Build

Medical billing code lookup tool for healthcare administrators
EHR (Electronic Health Record) integration for diagnosis entry
Medical student study app for learning diagnosis codes
Clinical documentation improvement assistant
Healthcare claims processing validation system