Developer Tools That Run in Your Browser
Free. Fast. Secure. No tracking. All processing happens locally in your browser. Your data never leaves your device.
Popular Tools
Most used developer utilities and converters
Number Base Converter — Binary, Hex, Decimal & Octal
conversion
Convert between binary, hex, decimal, octal and any base (2-36) instantly. Free, private — all processing in your browser.
Base64 Decoder & Encoder
encoding
Decode and encode Base64 online for free. Real-time conversion with full UTF-8 and emoji support. 100% private — runs in your browser. No signup needed.
Crontab Generator & Cron Expression Builder
datetime
Build, validate, and decode cron expressions in your browser. Live next-run preview in local time or UTC. POSIX 5-field syntax, presets, plain-English description. Free, private, no signup.
CSV to JSON Converter
encoding
Convert CSV to JSON in your browser. RFC 4180, type inference, header row, big-int safe. 100% private, no upload.
Compress Images Online — JPEG, PNG & WebP
conversion
Compress JPEG, PNG, WebP & AVIF up to 80% smaller — in your browser, no upload. Batch 20 images, resize, compare before & after, download as ZIP. Free & private.
JSON Diff & Compare
encoding
Compare two JSON files instantly in your browser. Side-by-side highlighting, RFC 6902 JSON Patch output, ignore noisy fields like timestamps and IDs. 100% private, no upload.
JSON Formatter & Validator
encoding
Format, validate and beautify JSON instantly in your browser. Free online tool with syntax validation, error detection, minify and one-click copy. 100% private.
JSON Schema Validator
encoding
Validate JSON against any JSON Schema instantly in your browser. Supports Draft 2020-12, 2019-09, and Draft-07 with path-precise error messages. 100% private — no upload, no account, free.
JSON to CSV Converter
encoding
Convert JSON to CSV in your browser. RFC 4180, Excel-EU, TSV, Pipe presets. Flatten nested or stringify. 100% private, no upload.
JSON to YAML Converter
encoding
Paste JSON, get YAML instantly. Live conversion in your browser. K8s/Compose-ready, 2/4-space indent, smart quoting. 100% private, no upload.
JWT Decoder
security
Decode JWT tokens online with our free JWT decoder. Instantly inspect header, payload, signature, expiration, algorithm, and claims. 100% browser-based — your token never leaves your device. No signup, no tracking.
Length Unit Converter — Metric, Imperial & More
conversion
Convert between 16 length units instantly — metric, imperial, nautical & astronomical. 1 inch = 2.54 cm. Free, private, runs in your browser.
Browse by Category
Find tools organized by their function
Encoding & Formatting
10 toolsConvert and format data between different encodings and formats
Security Tools
4 toolsHash generators, encryption utilities, and security validation tools
Date & Time
2 toolsUnix timestamp converters, timezone tools, and date formatters
Conversion Tools
6 toolsUnit converters, number system converters, and data transformation utilities
Latest from the Blog
Developer tutorials, guides, and insights
Regex cheat sheet: metacharacters, groups, and lookarounds
Regex cheat sheet: metacharacters, quantifiers, anchors, groups, lookarounds, plus 15+ JavaScript and Python patterns and concrete fixes for catastrophic backtracking.
HTTP Status Codes Cheat Sheet: Every Code Explained (1xx-5xx)
Complete HTTP status codes reference: 1xx through 5xx explained with real examples, common mistakes (401 vs 403, 301 vs 302), and SEO impact. Try our tools.
Your Data Stays Private
All processing happens in your browser — nothing is sent to external servers. No tracking, no cookies, no data collection. Most tools even work offline.