Developer Tools
All tools are free. No account, subscription or API key required.
Merge PDF, split PDF, format JSON, encode Base64, generate UUIDs — each tool has its own page for search and sharing.
JSON Formatter
FreePretty print and validate JSON
Formatters →Base64 Encoder
FreeEncode and decode Base64 strings
Encoders →UUID Generator
FreeCreate unique IDs instantly
Generators →SQL Formatter
FreeClean up messy SQL queries
Formatters →Regex Tester
FreeTest patterns against sample text
Testers →Hash Generator
FreeMD5, SHA-1, SHA-256 hashes
Generators →URL Encoder
FreeEncode and decode URL strings
Encoders →JWT Decoder
FreeInspect JWT header and payload
Decoders →Timestamp Converter
FreeUnix time ↔ human date
Converters →Markdown Preview
FreeWrite markdown, see HTML preview
Preview →JSON to Code Generator
FreeGenerate TypeScript types, JSON Schema and Laravel validation rules.
Generators →Text & JSON Diff Checker
FreeCompare text or inspect changes between JSON documents.
Testers →Mock Data Generator
FreeCreate sample users, products and orders as JSON, CSV or SQL.
Generators →cURL to Code Converter
FreeConvert a cURL request to Fetch, Python or Laravel code.
Converters →Cron Builder & Explainer
FreeBuild a schedule and preview upcoming runs in your timezone.
Generators →Merge PDF
FreeCombine PDF files in your chosen order.
PDF →Online Compiler
Open compiler →Write and run JavaScript, Python, HTML and CSS in our Online Compiler.
Tool questions
Are Codementrix developer tools free?
Yes. Every public tool is free and does not require an account or API key.
Can I merge PDF files online here?
Yes. Open the Merge PDF tool, add files in order, and download the combined PDF. Processing stays in your browser.
Do files upload to a server?
PDF and formatter tools run in your browser. We do not ask you to create an account to use them.