Developer utilities
Developer tools hub
Eight free tools for everyday developer tasks. Browser first, no signup, no bloat. AI assisted where it actually adds value.
Browser based tools
Instant · No API callsJSON Formatter
Format, minify, and validate JSON. Split-pane view with error highlighting.
JWT Decoder
Decode JWT tokens into header, payload, and signature. Shows expiry status.
TypeScript Interface Generator
Paste a JSON sample and get a fully typed TypeScript interface — handles nested objects and arrays.
ENV Example Generator
Paste your .env file and get a clean .env.example with smart placeholders. Never leaves your browser.
AI assisted tools
Powered by GPT-4oRegex Generator
Describe the pattern in plain English. Get a regex, an explanation, variants, and live test results.
Cron Expression Generator
Describe your schedule in natural language and get the cron expression with the next 5 scheduled runs.
SQL Query Explainer
Paste any SQL query and get a plain-English explanation of each clause plus performance notes.
API Response Mock Generator
Name an entity and define its fields. Get realistic mock data: single object, array, paginated, and TypeScript type.
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Frequently asked questions
Which of these tools work without an internet connection?
The JSON formatter, JWT decoder and generator, TypeScript interface generator, and ENV example generator all run entirely in your browser. They process data locally with no server calls, so they work offline and no data ever leaves your device. The regex generator, cron expression generator, SQL query explainer, and API mock generator use GPT-4o and require an internet connection.
Is the ENV example generator safe to use with real environment files?
Yes. The ENV example generator processes your .env file entirely in your browser using JavaScript — the file content is never sent to any server. It is designed specifically for use with real environment files so it can intelligently redact values like database URLs, API keys, and secrets while preserving safe values like port numbers and feature flags.
How accurate is the AI generated SQL explanation?
The SQL explainer uses GPT-4o and is highly accurate for standard SQL patterns including SELECT statements, JOINs, CTEs, subqueries, and window functions. It may miss dialect-specific behaviour in MySQL, PostgreSQL, or SQL Server edge cases. Treat the explanation as a strong starting point for understanding unfamiliar queries, not as a substitute for reading your database's official documentation for production decisions.
Can I use the regex generator output directly in production?
The generated regex is a reliable starting point but should always be tested against your specific inputs before use in production. The tool includes a live test area where you can paste sample strings. Pay particular attention to edge cases: empty strings, strings with special characters, and strings at the boundary of what should and should not match. The generator also shows alternative patterns, which can be useful for performance-sensitive applications.