Developer API — REST v1

Integrate any tool
into your workflow.

Access 15+ utility tools via REST API. Parse, validate, convert, and generate — all from a single integration. Free tier with 1,000 calls per month.

Get started →View endpoints →

Quick start

Three steps to your first call.

1. Get your API key

Create a free account to get your API key. You can find it in your account dashboard. No credit card required for the free tier.

2. Make your first request

All endpoints accept POST requests with a JSON body. Pass your API key in the X-API-Key header.

— terminal

curl -X POST https://toolforte.com/api/v1/tools/json-formatter \
  -H "Content-Type: application/json" \
  -H "X-API-Key: your_api_key_here" \
  -d '{"json": "{\"name\": \"ToolForte\"}", "indent": 2}'

3. Handle the response

Every response returns JSON with the tool-specific result. On success you get a 200 status code.

— response.json

{
  "formatted": "{\n  \"name\": \"ToolForte\"\n}",
  "valid": true
}

Authentication

API key in every header.

Authenticate every request by including your API key in the X-API-Key header. Never expose your key in client-side code or public repositories.

— terminal

curl -X POST https://toolforte.com/api/v1/tools/uuid-generator \
  -H "Content-Type: application/json" \
  -H "X-API-Key: tf_live_abc123def456" \
  -d '{"count": 1}'

Security tip. Keep your API key server-side. If you suspect a key has been compromised, rotate it immediately from your dashboard.

Pricing

Start free. Upgrade when you need more.

Free

— 1,000 calls/month
— 10 requests/minute

—All 15 endpoints
—JSON responses
—Standard support

Popular

Dev

€19/month

— 50,000 calls/month
— 60 requests/minute

—All 15 endpoints
—Priority queue
—Email support
—Usage dashboard

Scale

€99/month

— 500,000 calls/month
— 300 requests/minute

—All 15 endpoints
—Priority queue
—Dedicated support
—Usage dashboard
—Webhook notifications
—Custom rate limits

Rate limits

Transparent limits.

— Plan	— Monthly calls	— Rate limit	— Burst
Free	1,000	10 req/min	5 req/sec
Dev	50,000	60 req/min	20 req/sec
Scale	500,000	300 req/min	50 req/sec

Rate limit headers are included in every response: X-RateLimit-Limit, X-RateLimit-Remaining, and X-RateLimit-Reset.

Endpoints

15 REST endpoints.

All endpoints accept POST requests with a JSON body and return JSON responses.

— Text Diff — JSON Formatter — Markdown to HTML — CSV to JSON — URL Encoder/Decoder — Base64 Encode/Decode — Regex Tester — Color Converter — Password Strength — Word Counter — Cron Parser — UUID Generator — IBAN Validator — Slug Generator — Email Validator

POST/api/v1/tools/text-diff

Text Diff

Compare two texts and return a structured diff with additions, deletions, and unchanged lines.

— Request body

— request.json

{
  "original": "Hello world",
  "modified": "Hello there, world!"
}

— Response

— response.json

{
  "changes": [
    {
      "type": "equal",
      "value": "Hello "
    },
    {
      "type": "delete",
      "value": "world"
    },
    {
      "type": "insert",
      "value": "there, world!"
    }
  ]
}

— curl example

— terminal

curl -X POST https://toolforte.com/api/v1/tools/text-diff \
  -H "Content-Type: application/json" \
  -H "X-API-Key: your_api_key_here" \
  -d '{"original":"Hello world","modified":"Hello there, world!"}'

POST/api/v1/tools/json-formatter

JSON Formatter

Format, validate, and prettify JSON strings. Returns formatted output or validation errors.

— Request body

— request.json

{
  "json": "{\"name\":\"ToolForte\",\"version\":1}",
  "indent": 2
}

— Response

— response.json

{
  "formatted": "{\n  \"name\": \"ToolForte\",\n  \"version\": 1\n}",
  "valid": true
}

— curl example

— terminal

curl -X POST https://toolforte.com/api/v1/tools/json-formatter \
  -H "Content-Type: application/json" \
  -H "X-API-Key: your_api_key_here" \
  -d '{"json":"{\"name\":\"ToolForte\",\"version\":1}","indent":2}'

POST/api/v1/tools/markdown-to-html

Markdown to HTML

Convert Markdown content to sanitized HTML. Supports GFM tables, code blocks, and task lists.

— Request body

— request.json

{
  "markdown": "# Hello\n\nThis is **bold** text."
}

— Response

— response.json

{
  "html": "<h1>Hello</h1>\n<p>This is <strong>bold</strong> text.</p>"
}

— curl example

— terminal

curl -X POST https://toolforte.com/api/v1/tools/markdown-to-html \
  -H "Content-Type: application/json" \
  -H "X-API-Key: your_api_key_here" \
  -d '{"markdown":"# Hello\n\nThis is **bold** text."}'

POST/api/v1/tools/csv-to-json

CSV to JSON

Parse CSV data into a JSON array of objects. Auto-detects delimiters and handles quoted fields.

— Request body

— request.json

{
  "csv": "name,age\nAlice,30\nBob,25",
  "delimiter": ","
}

— Response

— response.json

{
  "data": [
    {
      "name": "Alice",
      "age": "30"
    },
    {
      "name": "Bob",
      "age": "25"
    }
  ],
  "rows": 2,
  "columns": 2
}

— curl example

— terminal

curl -X POST https://toolforte.com/api/v1/tools/csv-to-json \
  -H "Content-Type: application/json" \
  -H "X-API-Key: your_api_key_here" \
  -d '{"csv":"name,age\nAlice,30\nBob,25","delimiter":","}'

POST/api/v1/tools/url-encoder

URL Encoder/Decoder

Encode or decode URL components. Handles special characters and unicode.

— Request body

— request.json

{
  "text": "hello world & foo=bar",
  "mode": "encode"
}

— Response

— response.json

{
  "result": "hello%20world%20%26%20foo%3Dbar"
}

— curl example

— terminal

curl -X POST https://toolforte.com/api/v1/tools/url-encoder \
  -H "Content-Type: application/json" \
  -H "X-API-Key: your_api_key_here" \
  -d '{"text":"hello world & foo=bar","mode":"encode"}'

POST/api/v1/tools/base64

Base64 Encode/Decode

Encode text to Base64 or decode Base64 strings back to plain text.

— Request body

— request.json

{
  "text": "Hello, ToolForte!",
  "mode": "encode"
}

— Response

— response.json

{
  "result": "SGVsbG8sIFRvb2xGb3J0ZSE="
}

— curl example

— terminal

curl -X POST https://toolforte.com/api/v1/tools/base64 \
  -H "Content-Type: application/json" \
  -H "X-API-Key: your_api_key_here" \
  -d '{"text":"Hello, ToolForte!","mode":"encode"}'

POST/api/v1/tools/regex-tester

Regex Tester

Test a regular expression against a string. Returns all matches with groups and indices.

— Request body

— request.json

{
  "pattern": "(\\d{4})-(\\d{2})-(\\d{2})",
  "flags": "g",
  "text": "Today is 2026-04-08 and tomorrow is 2026-04-09."
}

— Response

— response.json

{
  "matches": [
    {
      "match": "2026-04-08",
      "index": 9,
      "groups": [
        "2026",
        "04",
        "08"
      ]
    },
    {
      "match": "2026-04-09",
      "index": 37,
      "groups": [
        "2026",
        "04",
        "09"
      ]
    }
  ],
  "count": 2
}

— curl example

— terminal

curl -X POST https://toolforte.com/api/v1/tools/regex-tester \
  -H "Content-Type: application/json" \
  -H "X-API-Key: your_api_key_here" \
  -d '{"pattern":"(\\d{4})-(\\d{2})-(\\d{2})","flags":"g","text":"Today is 2026-04-08 and tomorrow is 2026-04-09."}'

POST/api/v1/tools/color-converter

Color Converter

Convert colors between HEX, RGB, HSL, and HSB formats. Returns all representations.

— Request body

— request.json

{
  "color": "#4338ca",
  "format": "hex"
}

— Response

— response.json

{
  "hex": "#4338ca",
  "rgb": {
    "r": 67,
    "g": 56,
    "b": 202
  },
  "hsl": {
    "h": 245,
    "s": 58,
    "l": 51
  },
  "hsb": {
    "h": 245,
    "s": 72,
    "b": 79
  }
}

— curl example

— terminal

curl -X POST https://toolforte.com/api/v1/tools/color-converter \
  -H "Content-Type: application/json" \
  -H "X-API-Key: your_api_key_here" \
  -d '{"color":"#4338ca","format":"hex"}'

POST/api/v1/tools/password-strength

Password Strength

Analyze password strength and return a score with detailed feedback and suggestions.

— Request body

— request.json

{
  "password": "MyS3cur3P@ss!"
}

— Response

— response.json

{
  "score": 4,
  "label": "Strong",
  "crack_time": "centuries",
  "feedback": {
    "suggestions": [],
    "warning": null
  }
}

— curl example

— terminal

curl -X POST https://toolforte.com/api/v1/tools/password-strength \
  -H "Content-Type: application/json" \
  -H "X-API-Key: your_api_key_here" \
  -d '{"password":"MyS3cur3P@ss!"}'

POST/api/v1/tools/word-counter

Word Counter

Count words, characters, sentences, and paragraphs. Estimates reading and speaking time.

— Request body

— request.json

{
  "text": "The quick brown fox jumps over the lazy dog."
}

— Response

— response.json

{
  "words": 9,
  "characters": 44,
  "characters_no_spaces": 36,
  "sentences": 1,
  "paragraphs": 1,
  "reading_time_seconds": 2
}

— curl example

— terminal

curl -X POST https://toolforte.com/api/v1/tools/word-counter \
  -H "Content-Type: application/json" \
  -H "X-API-Key: your_api_key_here" \
  -d '{"text":"The quick brown fox jumps over the lazy dog."}'

POST/api/v1/tools/cron-parser

Cron Parser

Parse a cron expression into a human-readable description and list the next N scheduled runs.

— Request body

— request.json

{
  "expression": "0 9 * * MON-FRI",
  "count": 3
}

— Response

— response.json

{
  "description": "At 09:00 on every day-of-week from Monday through Friday",
  "next_runs": [
    "2026-04-09T09:00:00Z",
    "2026-04-10T09:00:00Z",
    "2026-04-11T09:00:00Z"
  ],
  "valid": true
}

— curl example

— terminal

curl -X POST https://toolforte.com/api/v1/tools/cron-parser \
  -H "Content-Type: application/json" \
  -H "X-API-Key: your_api_key_here" \
  -d '{"expression":"0 9 * * MON-FRI","count":3}'

POST/api/v1/tools/uuid-generator

UUID Generator

Generate one or more UUIDs (v4). Optionally return as uppercase or without dashes.

— Request body

— request.json

{
  "count": 2,
  "uppercase": false
}

— Response

— response.json

{
  "uuids": [
    "f47ac10b-58cc-4372-a567-0e02b2c3d479",
    "7c9e6679-7425-40de-944b-e07fc1f90ae7"
  ]
}

— curl example

— terminal

curl -X POST https://toolforte.com/api/v1/tools/uuid-generator \
  -H "Content-Type: application/json" \
  -H "X-API-Key: your_api_key_here" \
  -d '{"count":2,"uppercase":false}'

POST/api/v1/tools/iban-validator

IBAN Validator

Validate an IBAN number. Returns country, bank code, and checksum verification.

— Request body

— request.json

{
  "iban": "DE89370400440532013000"
}

— Response

— response.json

{
  "valid": true,
  "country": "Germany",
  "country_code": "DE",
  "bank_code": "37040044",
  "checksum": "89"
}

— curl example

— terminal

curl -X POST https://toolforte.com/api/v1/tools/iban-validator \
  -H "Content-Type: application/json" \
  -H "X-API-Key: your_api_key_here" \
  -d '{"iban":"DE89370400440532013000"}'

POST/api/v1/tools/slug-generator

Slug Generator

Convert any text into a URL-friendly slug. Handles unicode, diacritics, and special characters.

— Request body

— request.json

{
  "text": "Hello World! This is a Test.",
  "separator": "-"
}

— Response

— response.json

{
  "slug": "hello-world-this-is-a-test"
}

— curl example

— terminal

curl -X POST https://toolforte.com/api/v1/tools/slug-generator \
  -H "Content-Type: application/json" \
  -H "X-API-Key: your_api_key_here" \
  -d '{"text":"Hello World! This is a Test.","separator":"-"}'

POST/api/v1/tools/email-validator

Email Validator

Validate email address syntax and check for common typos in popular domain names.

— Request body

— request.json

{
  "email": "user@gmial.com"
}

— Response

— response.json

{
  "valid": true,
  "syntax_ok": true,
  "suggestion": "user@gmail.com",
  "disposable": false
}

— curl example

— terminal

curl -X POST https://toolforte.com/api/v1/tools/email-validator \
  -H "Content-Type: application/json" \
  -H "X-API-Key: your_api_key_here" \
  -d '{"email":"user@gmial.com"}'

Error codes

When things go wrong.

400

Bad Request

The request body is missing required fields or contains invalid data.

{ "error": "Missing required field: text", "code": 400 }

401

Unauthorized

API key is missing, invalid, or has been revoked.

{ "error": "Invalid or missing API key", "code": 401 }

429

Too Many Requests

You have exceeded the rate limit for your plan. Check the Retry-After header.

{ "error": "Rate limit exceeded. Retry after 30 seconds", "code": 429, "retry_after": 30 }

500

Internal Server Error

Something went wrong on our end. If this persists, contact support.

{ "error": "Internal server error", "code": 500 }

Base URL

One endpoint root.

https://toolforte.com/api/v1/tools/

All API traffic is served over HTTPS. HTTP requests are automatically redirected. The API supports gzip and brotli compression via the Accept-Encoding header.