# Developer Tools

Updated October 10, 2026

Twenty free developer tools that run entirely in your browser: encoders, decoders, formatters, generators, converters and testers. No sign-up, no uploads, nothing leaves your device. Pick a tool below.

- [**Base64 Encoder and Decoder**Encode text to Base64 or decode it back, with full Unicode support.](/base64-encoder-decoder/)
- [**URL Encoder and Decoder**Percent-encode URLs or decode them back to readable text.](/url-encoder-decoder/)
- [**JWT Decoder**Decode JWT header and payload, with expiry in plain dates.](/jwt-decoder/)
- [**Unix Timestamp Converter**Convert Unix timestamps to dates and back, with auto unit detection.](/unix-timestamp-converter/)
- [**UUID Generator**Generate random version 4 UUIDs, single or bulk.](/uuid-generator/)
- [**Regex Tester**Test regex patterns live with highlighting and capture groups.](/regex-tester/)
- [**Hash Generator**Compute MD5, SHA-1 and SHA-2 hashes of any text.](/hash-generator/)
- [**Lorem Ipsum Generator**Generate lorem ipsum placeholder text for mockups.](/lorem-ipsum-generator/)
- [**Markdown Preview**Live markdown editor with instant HTML preview.](/markdown-preview/)
- [**HTML Entity Encoder / Decoder**Encode text to HTML entities and decode them back.](/html-entity-encoder-decoder/)
- [**CSS Minifier**Compress CSS by removing comments and whitespace.](/css-minifier/)
- [**JavaScript Minifier**Compress JavaScript by stripping comments and whitespace.](/javascript-minifier/)
- [**SQL Formatter**Format messy SQL into clean, readable queries.](/sql-formatter/)
- [**XML Formatter & Validator**Pretty-print, minify and validate XML documents.](/xml-formatter-validator/)
- [**JSON to YAML Converter**Convert JSON documents into clean YAML.](/json-to-yaml-converter/)
- [**Cron Expression Explainer**Translate cron expressions into plain-English schedules.](/cron-expression-explainer/)
- [**Diff Checker**Compare two texts line by line with highlighted changes.](/diff-checker/)
- [**Slug Generator**Turn headlines into clean, SEO-friendly URL slugs.](/slug-generator/)
- [**Chmod Calculator**Compute Unix file permissions: octal, symbolic and chmod command.](/chmod-calculator/)
- [**Number Base Converter**Convert numbers between binary, octal, decimal and hex.](/number-base-converter/)

## More developer tools

- [**JSON Formatter and Validator**Format, minify, and validate JSON right in your browser.](/json-formatter-validator/)
- [**QR Code Generator**Make QR codes for URLs, text, and contact info. Custom colors, PNG download.](/qr-code-generator/)
- [**Password Generator**Crypto-random passwords with a strength meter.](/password-generator/)
- [**Character Counter**Characters, bytes, X remaining and SMS segments live.](/character-counter/)
- [**Case Converter**UPPER, lower, Title, Sentence, camel, snake and kebab case.](/case-converter/)
- [**Color Tools**Picker, HEX/RGB/HSL converter, palettes and contrast checker.](/color-tools/)

## Frequently asked questions

### Are these developer tools free?

Yes. Every tool on this page is free forever, with no account, no limits and no watermarks. They are funded the same way as the rest of Toolantern.

### Do I need to install anything?

No. Each tool runs in any modern browser, on desktop or mobile. Once the page loads, most tools keep working even if your connection drops.

### Is my code or data sent to a server?

No. All processing happens locally in your browser with JavaScript, so tokens, keys and proprietary code never leave your device. That is also why the JWT decoder warns you never to paste signing secrets: a decoder only needs the token, not the secret.

### Which tools do developers use most?

The JSON formatter, Base64 encoder, JWT decoder, regex tester and hash generator are the classics. For scheduling, the cron explainer and Unix timestamp converter save the most head-scratching.