Formatters, encoders, decoders and validators for everyday development work. Everything runs locally in your browser.
Every tool below runs entirely in your browser. Nothing you type or upload is sent to a server, there is no account to create, and no page reloads.
All developer tools tools
| Tool | What it does |
|---|---|
| Base64 Encoder & Decoder | Encode or decode Base64 and URL-encoded text instantly. Supports UTF-8, large payloads, and one-click copy. Nothing leaves your browser. |
| CSV to JSON Converter | Convert CSV to JSON with a live table preview. Handles quoted fields, embedded commas and newlines per RFC 4180. Runs in your browser. |
| Hash Generator | Compute SHA-1, SHA-256, SHA-384 and SHA-512 digests plus CRC32 checksums of any text, right in your browser. No uploads, no server. |
| HTML Entity Encoder | Escape or unescape HTML special characters. Convert &, <, >, quotes and named entities to safe code for safe HTML output. |
| IPv4 Converter | Convert IPv4 addresses to decimal, hex, binary and CIDR notation. See subnet ranges, address class and whether the address is private. |
| JSON Formatter | Format, validate and minify JSON instantly with syntax highlighting and precise error location. Runs 100% in your browser — nothing is uploaded. |
| JSON to CSV Converter | Convert a JSON array into CSV for Excel, Google Sheets or any spreadsheet. Handles nested objects and missing keys. Runs in your browser. |
| JWT Decoder | Decode and inspect JSON Web Tokens locally. See the header, payload, registered claims and expiry status. Signatures are not verified. |
| Regex Tester | Test regular expressions against your text with live match highlighting. Shows every match, its index and capture groups. |
| Timestamp Converter | Convert Unix timestamps to human-readable dates and back. Handles seconds, milliseconds, ISO 8601 and relative time. Timezone-aware. |
| URL Encoder & Decoder | Percent-encode or decode URLs and query strings. See the difference between encodeURI and encodeURIComponent. Runs in your browser. |
| UUID Generator | Generate UUID v4 (random) or v1 (time-based) identifiers in bulk. Cryptographically secure, no tracking, no database. Nothing leaves your browser. |
The tools in detail
Base64 Encoder & Decoder
Encode or decode Base64 and URL-encoded text instantly. Supports UTF-8, large payloads, and one-click copy. Nothing leaves your browser.
Open Base64 Encoder & Decoder →
CSV to JSON Converter
Convert CSV to JSON with a live table preview. Handles quoted fields, embedded commas and newlines per RFC 4180. Runs in your browser.
Hash Generator
Compute SHA-1, SHA-256, SHA-384 and SHA-512 digests plus CRC32 checksums of any text, right in your browser. No uploads, no server.
HTML Entity Encoder
Escape or unescape HTML special characters. Convert &, <, >, quotes and named entities to safe code for safe HTML output.
IPv4 Converter
Convert IPv4 addresses to decimal, hex, binary and CIDR notation. See subnet ranges, address class and whether the address is private.
JSON Formatter
Format, validate and minify JSON instantly with syntax highlighting and precise error location. Runs 100% in your browser — nothing is uploaded.
JSON to CSV Converter
Convert a JSON array into CSV for Excel, Google Sheets or any spreadsheet. Handles nested objects and missing keys. Runs in your browser.
JWT Decoder
Decode and inspect JSON Web Tokens locally. See the header, payload, registered claims and expiry status. Signatures are not verified.
Regex Tester
Test regular expressions against your text with live match highlighting. Shows every match, its index and capture groups.
Timestamp Converter
Convert Unix timestamps to human-readable dates and back. Handles seconds, milliseconds, ISO 8601 and relative time. Timezone-aware.
URL Encoder & Decoder
Percent-encode or decode URLs and query strings. See the difference between encodeURI and encodeURIComponent. Runs in your browser.
UUID Generator
Generate UUID v4 (random) or v1 (time-based) identifiers in bulk. Cryptographically secure, no tracking, no database. Nothing leaves your browser.
Why these run in your browser
Every tool on this site is client-side. That is a deliberate choice, and it has three practical consequences.
Your data stays on your machine. There is no upload step, no server processing and nothing stored. You can confirm this yourself: open your browser's developer tools, switch to the Network tab and use any tool. Nothing is sent.
Results are instant. There is no round trip to wait for, so the output appears as fast as the browser can compute it.
It is free. There is no server cost per request to pass on, which is why there is no paywall and no usage cap.