Free online Developer tools

12 tools — all free, no sign-up, processed locally in your browser.

Format and validate JSON, convert JSON and YAML, encode Base64 and URLs, test regular expressions, convert timestamps, explain cron expressions, format SQL, compute hashes, generate passwords and encrypt locally. Everyday utilities for developers and API debugging.

JSON formatter and validator

Format, validate, extract paths, unescape strings and convert JSONL while preserving number literals.

JSON diff

Compare JSON precisely, match array keys, ignore paths and export complete reports.

JSON and YAML converter

Convert and validate JSON and YAML while preserving large integers and decimal precision.

Regex tester

Highlight matches, preview replacements, save reusable rules and verify expressions with positive and negative tests.

Timestamp and time zone converter

Convert timestamps from seconds to nanoseconds in batches with multiple time zones and DST handling.

UUID generator

Generate one or many UUIDs locally in your browser.

Password generator

Generate secure passwords in batches, choose character groups, exclude confusing characters and copy or download.

SHA-256 hash

Calculate SHA-256 digests for text or files.

JWT viewer

Inspect a JWT header and payload locally without verifying its signature.

Cron expression and run times

Explain cron schedules and preview upcoming runs in a chosen time zone with local presets.

SQL formatter

Format SQL dialects including MySQL and PostgreSQL, with indentation and keyword case options.

Text and file encryption

Encrypt or decrypt text and files locally with a password using authenticated AES-256-GCM encryption.

Frequently asked questions

Will large numbers lose precision?

No. Number literals are kept as written, never converted through JavaScript floats, so IDs and long decimals stay exact.

Does a changed array order count as a difference?

Arrays compare by position by default. Specify a unique key for one array to match items regardless of order.

Are YAML comments kept?

No. Comments are removed during conversion.

Which regex flavor is used?

JavaScript (ECMAScript) syntax and flags.

How does it know seconds from milliseconds?

It never guesses. You choose seconds, milliseconds, microseconds or nanoseconds explicitly.

How many at once?

Up to 1,000 per run.

Other categories

Image tools18 tools QR & barcodes9 tools PDF tools13 tools Text tools13 tools Files & design15 tools