Developer Tools
Free online developer tools: JSON formatter, regex tester, Base64/URL encoder and more.
15 tools
Developer Tools collects small text utilities used while building or debugging: two encoders and two generators. The Base64 and URL encoders convert a string to and from a transport-safe form — Base64 for tokens and binary-ish payloads, percent-encoding for a single URL parameter. The SHA Hash Generator produces a SHA-256, SHA-384 or SHA-512 digest of the text you paste. The UUID Generator returns one random version-4 identifier from the browser's secure random source. Everything works on text in the browser with nothing sent out; the file-based equivalents live in File Conversion Tools.
Which tool should I use?
- Use the Base64 Encoder/Decoder for a text string; it needs standard padded Base64 and returns UTF-8 text. For a binary file or a data: URL, use Base64 File Encoder & Decoder in File Conversion Tools.
- Use the URL Encoder/Decoder to build or read one query-string value or path segment, not to encode a whole URL with its scheme and slashes.
- Use the SHA Hash Generator to hash a piece of text. To hash a file, or to produce a legacy SHA-1 checksum, use File Hash Generator in File Conversion Tools.
- Use the UUID Generator when you need a throwaway unique id; it produces one random v4 UUID at a time and nothing else.
Limitations and things to know
- The Base64 decoder rejects URL-safe Base64 (- and _) and unpadded input, and fails if the decoded bytes are not valid UTF-8 text.
- The URL encoder uses component encoding: the characters - _ . ! ~ * ' ( ) are left as-is, and an entire URL is not encoded correctly.
- The SHA Hash Generator offers no MD5 or SHA-1, hashes one algorithm at a time, and is capped at 2 MB of text.
- The UUID Generator makes only random version-4 UUIDs — no sortable v1/v7, no name-based v5, no bulk output — and errors instead of falling back to weak randomness if the browser has no secure RNG.
SVG Optimizer
Optimize SVG markup to reduce unnecessary data while keeping the vector image usable for web delivery.
Use toolSQL Formatter
Reformat SQL into a more readable layout for review and debugging without executing the query.
Use toolLine Ending Converter
Convert text line endings between common conventions such as LF and CRLF while leaving the textual content intact.
Use toolHex Viewer
Inspect file bytes in hexadecimal and text form for quick low-level checks without a desktop hex editor.
Use toolCron Expression Explainer & Builder
Build or inspect a cron expression and translate its fields into a more readable scheduling description.
Use toolRegex Tester
Test a regular expression against sample text and inspect matches without running code on a server.
Use toolSecure Token Generator
Generate cryptographically random token values locally for application secrets, test data or one-time identifiers.
Use toolHTTP Status Code Lookup
Look up common HTTP response codes by number or meaning and review what each status is intended to signal.
Use toolCSS Box Shadow Generator
Adjust shadow offsets, blur, spread and color, then copy the resulting CSS box-shadow declaration.
Use toolHTML Entity Encoder / Decoder
Encode HTML-sensitive characters as entities or decode entities back to readable text without sending the input anywhere.
Use toolNumber Base Converter
Convert whole numbers between common positional bases such as binary, octal, decimal and hexadecimal.
Use toolSHA Hash Generator
Hash pasted text with SHA-256, SHA-384 or SHA-512, one algorithm at a time; no MD5 or SHA-1.
Use toolUUID Generator
Generate one random RFC 4122 version-4 UUID from the browser's secure RNG; no v1/v5/v7, no bulk mode.
Use toolURL Encoder / Decoder
Percent-encode or decode one URL parameter or path segment; component encoding, not whole-URL encoding.
Use toolBase64 Encoder / Decoder
Encode or decode a text string as standard Base64, UTF-8 safe for accents and emoji; not for binary files.
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