Free developer toolbox · runs in your browser
Paste anything. Get the answer.
34 free tools for decoding, hashing, signing, converting and comparing. Paste a JWT, certificate, timestamp, UUID, cron line, IP range, XML or Base64 into Smart Paste and DevToolStation recognises it and opens the right tool. Nothing you enter leaves your browser, and everything works offline.
The toolbox
Format & Convert
Pretty-print, validate and reshape JSON, XML, CSV, numbers and colours.
- JSON Formatter & ValidatorPretty-print, minify, sort keys and validate JSON with precise error locations.
- XML Formatter & ValidatorPretty-print, minify and validate XML with the exact line and column of any error.
- JSON ↔ CSVConvert arrays of objects to CSV with flattened columns, and CSV back to JSON.
- XML ↔ JSONConvert XML to JSON (attributes as @keys, repeated elements as arrays) and JSON back to XML.
- JSON to TypeScriptGenerate TypeScript interfaces from a sample JSON response, merging array items.
- Number Base ConverterBinary, octal, decimal, hex and base 36 for numbers of any size, with two’s complement.
- Colour Converter & ContrastHEX, RGB, HSL and OKLCH conversion with WCAG contrast checks.
Encode & Decode
Base64, URLs, escaping, HTML entities and Unicode.
- Base64 Encode / DecodeText and files to Base64, Base64url and data: URLs, and back.
- URL Encoder & ParserPercent-encode and decode, and split a URL into parts and query parameters.
- String Escape / UnescapeEscape and unescape strings for JSON, JavaScript, CSV, SQL, regex, shell and XML.
- HTML EntitiesEscape text for HTML and decode every named and numeric entity.
- Unicode InspectorFind hidden characters, zero-width spaces and Trojan Source bidi controls; see code points and bytes.
Compare
See exactly what changed between two versions of text, JSON or XML.
- Text CompareLine-by-line diff of any two texts or files, side by side or unified, with word-level highlights.
- JSON CompareStructural diff of two JSON documents, with ignored paths, key-matched arrays and breaking-change detection.
- XML CompareStructural diff of two XML documents, matching repeated elements by id and ignoring order and whitespace.
Security & Crypto
Decode tokens, hash, sign, encrypt and inspect certificates.
- JWT Decoder & SignerDecode JWTs, check expiry, verify HS, RS, PS, ES and EdDSA signatures, and sign HMAC tokens.
- Hash GeneratorMD5, SHA-1, SHA-256, SHA-384 and SHA-512 of text or files, and checksum verification.
- HMAC GeneratorHMAC-SHA signatures for webhooks and API request signing, in hex and Base64.
- AES Encrypt / DecryptPassword-based AES-256-GCM, or raw-key AES-GCM, CBC and CTR compatible with OpenSSL and Node.
- Certificate DecoderRead X.509 certificates and chains: subject, SANs, validity, key, extensions and fingerprints.
- TOTP / 2FA CodesLive one-time codes from a Base32 secret, plus otpauth:// URIs for testing 2FA flows.
Keys & Generators
IDs, passwords, secrets, key pairs and placeholder text.
- UUID / ULID GeneratorBulk UUID v4, time-ordered UUID v7 and ULID, and an inspector that reads embedded timestamps.
- Password GeneratorStrong random passwords with chosen character sets and an entropy estimate.
- Secret & API Key GeneratorCryptographically random API keys, AES keys, HMAC secrets and tokens in hex, Base64 or Base32.
- Key Pair GeneratorRSA, ECDSA, Ed25519, ECDH and X25519 key pairs as PEM, JWK and OpenSSH public keys.
- Lorem Ipsum GeneratorPlaceholder paragraphs, sentences or words for mock-ups and test data.
Text & Regex
Test patterns and clean up text.
Time & Scheduling
Timestamps, time zones and cron.
Web & Network
HTTP status codes, subnets and file permissions.