Free Developer Data API

Generate browser-safe developer identifiers, text transforms, hashes, dates, math helpers and non-sensitive CEP test data. No API key required.

No API key requiredCORS enabledJSON responses21 endpointsOpenAPI JSON
BASE URLhttps://www.4devtool.com/api

Quick start

Public endpoints return JSON and are designed for QA, demos, testing, automation, fixtures and browser-based development workflows.

curl
curl "https://www.4devtool.com/api/generate/uuid?count=3"
JavaScript
const response = await fetch("https://www.4devtool.com/api/generate/uuid?count=3");
const data = await response.json();
console.log(data);

Authentication

Authentication is not required. All public endpoints can be used without an API key.

Rate limits

Rate limits may be applied to protect service availability. Avoid excessive automated requests and cache responses when possible.

Responsible use

The API generates synthetic data for testing, QA, demos, development and automation. Do not use generated values for fraud, impersonation, real registrations or illegal activity.

Examples by use case

Generate UUIDs for test recordsValidate Brazilian CEP field formatsCreate hashes for QA fixturesEncode and decode Base64Calculate date differences for workflows

Brazil

2
GET/generate/cepGenerate Brazilian CEP

Generate Brazilian CEP

countinteger - optional - default 1 - min 1 - max 50
Success responseHTTP 200
{
  "success": true,
  "count": 1,
  "data": ["example"]
}
Error responseHTTP 400
{
  "success": false,
  "error": "Invalid value"
}
Open example
GET/validate/cepValidate Brazilian CEP format

Validate Brazilian CEP format

valuestring - required
Success responseHTTP 200
{
  "success": true,
  "valid": true,
  "input": "example"
}
Error responseHTTP 400
{
  "success": false,
  "error": "Invalid value"
}
Open example

Universal

19
GET/calculate/gcd-lcmCalculate GCD and LCM

Calculate GCD and LCM

No parametersReady to call
Success responseHTTP 200
{
  "success": true,
  "count": 1,
  "data": ["example"]
}
Error responseHTTP 400
{
  "success": false,
  "error": "Invalid value"
}
Open example
GET/calculate/percentageCalculate percentage values

Calculate percentage values

No parametersReady to call
Success responseHTTP 200
{
  "success": true,
  "count": 1,
  "data": ["example"]
}
Error responseHTTP 400
{
  "success": false,
  "error": "Invalid value"
}
Open example
GET/date/addAdd days to a date

Add days to a date

No parametersReady to call
Success responseHTTP 200
{
  "success": true,
  "count": 1,
  "data": ["example"]
}
Error responseHTTP 400
{
  "success": false,
  "error": "Invalid value"
}
Open example
GET/date/differenceCalculate difference between dates

Calculate difference between dates

No parametersReady to call
Success responseHTTP 200
{
  "success": true,
  "count": 1,
  "data": ["example"]
}
Error responseHTTP 400
{
  "success": false,
  "error": "Invalid value"
}
Open example
GET/decode/base64Decode Base64 to a string

Decode Base64 to a string

valuestring - optional
Success responseHTTP 200
{
  "success": true,
  "count": 1,
  "data": ["example"]
}
Error responseHTTP 400
{
  "success": false,
  "error": "Invalid value"
}
Open example
GET/decode/urlURL-decode a string

URL-decode a string

valuestring - optional
Success responseHTTP 200
{
  "success": true,
  "count": 1,
  "data": ["example"]
}
Error responseHTTP 400
{
  "success": false,
  "error": "Invalid value"
}
Open example
GET/encode/base64Encode a string to Base64

Encode a string to Base64

valuestring - optional
Success responseHTTP 200
{
  "success": true,
  "count": 1,
  "data": ["example"]
}
Error responseHTTP 400
{
  "success": false,
  "error": "Invalid value"
}
Open example
GET/encode/urlURL-encode a string

URL-encode a string

valuestring - optional
Success responseHTTP 200
{
  "success": true,
  "count": 1,
  "data": ["example"]
}
Error responseHTTP 400
{
  "success": false,
  "error": "Invalid value"
}
Open example
GET/generate/passwordGenerate secure passwords

Generate secure passwords

lengthinteger - optional - default 16uppercaseboolean - optional - default truenumbersboolean - optional - default truesymbolsboolean - optional - default falsecountinteger - optional - default 1
Success responseHTTP 200
{
  "success": true,
  "count": 1,
  "data": ["example"]
}
Error responseHTTP 400
{
  "success": false,
  "error": "Invalid value"
}
Open example
GET/generate/random-numberGenerate random numbers in a range

Generate random numbers in a range

mininteger - optional - default 1maxinteger - optional - default 100countinteger - optional - default 1
Success responseHTTP 200
{
  "success": true,
  "count": 1,
  "data": ["example"]
}
Error responseHTTP 400
{
  "success": false,
  "error": "Invalid value"
}
Open example
GET/generate/ulidGenerate ULID identifiers

Generate ULID identifiers

countinteger - optional - default 1 - min 1 - max 50
Success responseHTTP 200
{
  "success": true,
  "count": 1,
  "data": ["example"]
}
Error responseHTTP 400
{
  "success": false,
  "error": "Invalid value"
}
Open example
GET/generate/uuidGenerate UUID v4

Generate UUID v4

countinteger - optional - default 1 - min 1 - max 50
Success responseHTTP 200
{
  "success": true,
  "count": 1,
  "data": ["example"]
}
Error responseHTTP 400
{
  "success": false,
  "error": "Invalid value"
}
Open example
GET/hashHash a value with SHA algorithms

Hash a value with SHA algorithms

valuestring - requiredalgorithmstring - optional - default sha256
Success responseHTTP 200
{
  "success": true,
  "count": 1,
  "data": ["example"]
}
Error responseHTTP 400
{
  "success": false,
  "error": "Invalid value"
}
Open example
GET/transform/caseConvert text case

Convert text case

valuestring - required
Success responseHTTP 200
{
  "success": true,
  "count": 1,
  "data": ["example"]
}
Error responseHTTP 400
{
  "success": false,
  "error": "Invalid value"
}
Open example
GET/transform/remove-accentsRemove accents from text

Remove accents from text

valuestring - required
Success responseHTTP 200
{
  "success": true,
  "count": 1,
  "data": ["example"]
}
Error responseHTTP 400
{
  "success": false,
  "error": "Invalid value"
}
Open example
GET/transform/reverseReverse text

Reverse text

valuestring - required
Success responseHTTP 200
{
  "success": true,
  "count": 1,
  "data": ["example"]
}
Error responseHTTP 400
{
  "success": false,
  "error": "Invalid value"
}
Open example
GET/transform/slugConvert text to a URL slug

Convert text to a URL slug

valuestring - required
Success responseHTTP 200
{
  "success": true,
  "count": 1,
  "data": ["example"]
}
Error responseHTTP 400
{
  "success": false,
  "error": "Invalid value"
}
Open example
GET/transform/sort-linesSort lines alphabetically

Sort lines alphabetically

valuestring - required
Success responseHTTP 200
{
  "success": true,
  "count": 1,
  "data": ["example"]
}
Error responseHTTP 400
{
  "success": false,
  "error": "Invalid value"
}
Open example
GET/transform/truncateTruncate text

Truncate text

valuestring - required
Success responseHTTP 200
{
  "success": true,
  "count": 1,
  "data": ["example"]
}
Error responseHTTP 400
{
  "success": false,
  "error": "Invalid value"
}
Open example

API FAQ

Is the 4DevTool API free?

Yes. Public endpoints are free to use for QA, demos, development, testing and automation.

Does the API require an API key?

No. Authentication is not required for the public endpoints documented on this page.

Can I use the API from the browser?

Yes. CORS is enabled so browser-based prototypes and QA utilities can call the API directly.

Are generated values real?

No. Generated values are synthetic test data for QA, demos, development and automation.

Is there an OpenAPI specification?

Yes. The public OpenAPI JSON is available at /api-docs/openapi-public.json.