Developer Tools

Everyday conversion tools for developers and anyone who works with data. No install, no sign-up — and everything runs inside your browser.

JSON Formatter & Validator

Pretty-print or minify JSON and pinpoint syntax errors. Runs in your browser; nothing is sent to a server.

No upload · runs in your browser

Base64 Encoder & Decoder

Encode or decode text and files as Base64. Runs in your browser; nothing is sent to a server.

No upload · runs in your browser

UUID Generator

Generate UUID v4 and v7 in bulk and validate UUIDs. Generated in your browser, never sent to a server.

No upload · runs in your browser

Hash Calculator

MD5, SHA-1, SHA-256, SHA-512, SHA-3 and CRC32 hashes of text or files, with checksum verification. Runs in your browser; nothing is sent to a server.

No upload · runs in your browser

Universal String Decoder

Paste any string and find out what it is: Base64, JWT, URL encoding, hex, Unix timestamp, hash and more, decoded in steps. Runs in your browser; nothing is sent to a server.

No upload · runs in your browser

JWT Decoder

Decode a JWT's header and payload and see when it was issued and expires in your local time. Runs in your browser; the token is never sent to a server.

No upload · runs in your browser

URL Encoder & Decoder

Decode percent-encoded URLs and query strings, or URL-encode text with encodeURIComponent, encodeURI or form encoding. Runs in your browser; nothing is sent to a server.

No upload · runs in your browser

Unix Timestamp Converter

Convert Unix timestamps (seconds, milliseconds, microseconds, nanoseconds) to dates and dates back to timestamps. Runs in your browser; nothing is sent to a server.

No upload · runs in your browser

Fix Garbled Text (Mojibake)

Repair mojibake like â€™ or Ã© caused by wrong character encodings, and normalize decomposed Unicode. Runs in your browser; nothing is sent to a server.

No upload · runs in your browser

Excel to CSV Converter

Convert Excel (xlsx) to CSV and CSV to Excel. Processed in your browser, never sent to a server.

No upload · runs in your browser

Merge Excel Files

Combine multiple Excel and CSV files or sheets into one and remove duplicate rows. Processed in your browser, never sent to a server.

No upload · runs in your browser

Safe to paste

API responses, auth tokens and customer exports often contain sensitive data. These tools never send your text or files to a server and store nothing; once a page has loaded it keeps working offline.

What each tool does

JSON Formatter & Validator: pretty-print, minify and sort keys; errors reported by line and column with a plain-English explanation. Big numbers are preserved exactly.
Base64 Encoder & Decoder: correct UTF-8 for accents and emoji, URL-safe output, line wrapping, and files to Base64 or data URIs and back.
Universal String Decoder: paste any string and find out whether it is Base64, a JWT, URL encoding, hex, a timestamp, a hash or mojibake, unwrapped step by step. JWT, URL, timestamp and mojibake have dedicated pages.
Hash Calculator: MD5, SHA-1, SHA-256, SHA-512, SHA-3 and CRC32 for text and files, with checksum verification.
UUID Generator: up to 1,000 random v4 or time-ordered v7 UUIDs, plus a validator that decodes version and timestamp.
Excel to CSV Converter: xlsx ↔ CSV with a UTF-8 BOM so Excel shows accents correctly, and automatic encoding and delimiter detection.
Merge Excel Files: stack several Excel and CSV files or sheets into one, matching columns by name and removing duplicate rows by a key column.

Standards-compliant output

JSON follows RFC 8259, Base64 RFC 4648, UUIDs RFC 9562 and CSV RFC 4180, so results match other tools and programming languages. Each tool page explains the rules and the most common mistakes.