Developer

Convert a Base64 string to hexadecimal bytes and hex back to Base64, with URL-safe support, in your browser.

Developer

Encode text to MIME Quoted-Printable (RFC 2045) or decode it back — handling =XX escapes, soft line breaks and UTF-8, with 76-character wrapping.

Developer

Compute xxHash32/64, MurmurHash3 (32 and 128-bit), FNV-1/FNV-1a (32 and 64-bit) and SipHash-2-4 of text, hex bytes or a file, with seeds and a key.

Developer

Hash text, hex or a file with BLAKE3 (hash, keyed, derive-key), BLAKE2b/2s with key, salt and personalization, Keccak-256/512 or SHAKE128/256.

Developer

Compute the CRC-32 (IEEE 802.3, used by zip/gzip/PNG) or CRC-32C (Castagnoli) checksum of text or hex bytes, in hex and unsigned decimal.

Developer

Compute any CRC of 3 to 64 bits — Modbus, CCITT, XMODEM, CRC-64/XZ and 108 more presets, or your own parameters — and find which CRC gives a value.

Developer

Compute and verify check digits with Luhn, Verhoeff, Damm and the ISO 7064 family (MOD 11-2, 97-10, 37-2…), and see which typing errors each one catches.

Developer

Size a Bloom filter for n items at a target false-positive rate, or get a filter's error rate or capacity, with the best number of hash functions.

Developer

Paste any UUID to see its version (1–8), variant and — for time-based v1, v6 and v7 — the embedded timestamp, clock sequence and node/MAC.

Developer

Run an XPath expression against XML or HTML in your browser and see every node it matches, with namespace prefixes and parse errors reported.

Developer

Test a CSS selector against your HTML and see exactly which elements it matches, in your browser.

Developer

Generate TypeScript interfaces from any JSON sample — types are inferred recursively and named after each key.

Developer

Turn a JSON object into JSDoc @typedef blocks with @property tags, in your browser.

Developer

Generate realistic fake records for testing — names, emails, dates, IDs, lorem — exported as JSON, CSV, or SQL INSERTs.

Developer

Build and sign HS256 / HS384 / HS512 JWTs from a header and payload — pairs with the JWT Decoder.

Developer

Sign a message with an Ed25519 key or verify a signature in the browser, with the public key derived from the seed and R and S shown.

Developer

Generate an RSA, ECDSA, ECDH, Ed25519 or X25519 keypair in your browser and export it as PKCS#8 and SPKI PEM or as JWK.

Developer

Turn a JWK or a whole JWKS into PEM public keys and back, with the RFC 7638 thumbprint for each — computed in your browser.

Developer

Visually pick flex-direction, justify-content, align-items, and gap — copy the resulting CSS or Tailwind class.

Developer

Visually pick grid-template-columns / rows, gap, and item alignment — copy the CSS straight into your project.

Developer

Build a cron expression by clicking — hourly, daily, weekly, monthly, or fully custom — pairs with the Cron Explainer.

Developer

Spot NBSPs, zero-width characters, bidi marks, and tabs in pasted text — then clean them out.

Developer

Hash a password with Argon2id, Argon2i or Argon2d and get the $argon2id$ PHC string, or check a password against one. Runs in your browser.

Developer

Bulk-generate ULIDs, NanoIDs, and CUID2 — modern UUID alternatives that are shorter, sortable, or collision-resistant.

Developer

Decode a ULID into its 48-bit creation timestamp and 80-bit randomness — Crockford Base32, case-insensitive, with ISO UTC and epoch milliseconds.

Developer

Decode a Discord, Twitter/X or Instagram Snowflake ID into its creation timestamp, worker or datacenter, and sequence — with a custom-epoch mode.

Developer

Escape a string for 10 contexts at once — JavaScript, JSON, HTML entities, URL, SQL, regex, Bash (single/double quote), C string, Unicode \u escapes.

Developer

Derive a key from a password with PBKDF2-HMAC in your browser — pick the hash, iteration count and output length, and read the result as hex or Base64.

Developer

Derive a key from a password with scrypt in the browser, with the memory cost worked out and the PBKDF2 and ROMix stages shown.

Developer

Derive keys with HKDF and see both halves: the PRK from extract, every T block from expand, and the OKM in hex and base64. RFC 5869 cases built in.

Developer

Compute HMAC signatures with Web Crypto — sign webhook payloads, verify API requests, hex or base64 output.

Developer

Validate a card number with the Luhn checksum, detect brand (Visa/MC/Amex/etc), and check expected length. Local, no network.

Developer

Validate ISBN-10 and ISBN-13 checksums and convert between the two formats. Hyphens and spaces are handled.

Developer

Calculate or verify the GS1 modulo-10 check digit for EAN-13, UPC-A and EAN-8 barcodes.

Developer

AND, OR, XOR, NOT and bit shifts on two integers — shown in binary, hex, unsigned and signed decimal, with selectable 8, 16, 32 or 64-bit width.

Developer

Encode text to \uXXXX, U+XXXX or HTML entities — and decode any of those back to text. Handles emoji and astral characters.

Developer

Generate a deterministic, namespace-based UUID (version 5, SHA-1) from a namespace and a name — the same inputs always produce the same UUID.

Developer

Turn a JSON object into a typed Go struct with json tags, instantly in your browser.

Developer

Turn a JSON object into Python @dataclass definitions with type hints, in your browser.

Developer

Turn a JSON object into Rust structs with serde derives and type-mapped fields, in your browser.

Developer

Turn a JSON object into Kotlin data classes with typed properties, in your browser.

Developer

Turn a JSON object into C# classes with auto-property type mapping, in your browser.

Developer

Turn a JSON object into Java POJO classes with type-mapped fields, in your browser.

Developer

Turn a JSON object into a Zod validation schema with inferred types, in your browser.

Developer

Turn a JSON object into GraphQL type definitions (SDL) with scalar mapping, in your browser.

Developer

Turn a JSON object into a Mongoose schema with type-mapped paths, in your browser.

Developer

Test file paths against a glob pattern (*, **, ?, [...], {a,b}) in your browser.

Developer

Build a Conventional Commits message with type, scope, breaking change, and footers, in your browser.

Developer

Convert a CSS declaration block into a React/JS inline style object, in your browser.

Developer

Turn a JSON object into a proto3 .proto schema with typed fields and nested messages, in your browser.

Developer

Break a URL into protocol, host, port, path, query, and hash. Decode query parameters into a table.

Developer

Decode a data: URI to see its MIME type, encoding, size and decoded contents, in your browser.

Developer

Build a CSS animation visually — pick a preset, tweak duration/easing/iteration, see the preview, and copy the generated keyframes.

Developer

Inspect text or a small file as offset + hex bytes + printable ASCII, like xxd or hexdump -C.

Developer

Paste any CSS selector to see its (ID, class, type) specificity, per-token breakdown, and head-to-head comparison with another selector.

Developer

Run JSONPath queries ($.store.book[*].author, $..price) against a sample document and see the matching values.

Developer

Resolve an RFC 6901 JSON Pointer like /user/roles/0 against a document — with ~0/~1 escaping, URI fragments, and a clickable list of every pointer.

Developer

Convert internationalized domains between Unicode (münchen.de) and Punycode ASCII (xn--mnchen-3ya.de).

Developer

Format a number the way each locale expects — 1,234,567.89, 1.234.567,89, $1.23M, 12 345 ₽ — and grab the matching JavaScript snippet.

Developer

Sort the keys of a JSON object alphabetically. Optionally recurse into nested objects so the whole document is canonicalized.

Developer

Flatten nested JSON into dot-notation keys, or rebuild nested JSON from flat keys — configurable delimiter and array notation, fully reversible.

Developer

Encode and decode Base32 (RFC 4648), with standard and base32hex variants — useful for TOTP secrets and Crockford-style IDs.

Developer

Encode and decode Base58 with the Bitcoin, Ripple or Flickr alphabet — from UTF-8 text or raw hex, with correct leading-zero handling.

Developer

Decode any bech32 or bech32m string: human-readable part, data symbols, witness version, program and scriptPubKey — and which checksum it verifies under.

Developer

Encrypt and decrypt with AEAD_CHACHA20_POLY1305 in your browser, with the Poly1305 one-time key and the counter split shown.

Developer

Encrypt and decrypt with AES-GCM in your browser: hex key and nonce, optional AAD, selectable tag length, and the ciphertext and tag kept apart.

Developer

Encode and decode Ascii85 (Base85) from UTF-8 text or hex bytes — Adobe/PDF variant with <~ ~> delimiters, or the plain variant. All in your browser.

Developer

Encode text to Base45 and decode Base45 back to text, following RFC 9285, in your browser.

Developer

Find the MIME type for a file extension (or the other way around) and learn what each type is for.

Developer

Searchable reference for ~50 standard HTTP request, response, CORS, caching, security, and cookie headers.

Developer

Paste a cURL command — get ready-to-use JS fetch or axios code with headers, body, method, and basic auth handled.

Developer

Turn a docker run command into a docker-compose.yml — ports, volumes, environment and limits mapped for you.

Developer

Build a .service unit file for systemd — Type, Restart, User, Environment, sandboxing — plus the install and journalctl commands.

Developer

Read an SSH public key, authorized_keys or known_hosts line: algorithm, key size, SHA256 and MD5 fingerprints, comment and options.

Developer

Decode a MongoDB BSON file in your browser: every element type with its type byte, exact int64 and decimal128, and canonical or relaxed Extended JSON.

Developer

Parse a .properties file exactly as java.util.Properties.load does — separators, escapes, continuations — and see every line that will surprise you.

Developer

Disassemble a .pkl file in the browser: every opcode, the memo, the value it rebuilds, and whether loading it would run code.

Developer

Open a .pyc from __pycache__ in your browser: which CPython wrote it, timestamp or hash invalidation, the code object tree and the disassembly.

Developer

Read a .npy or .npz header in the browser: dtype, shape, byte order, field layout and a value preview, with no NumPy and no upload.

Developer

Read a .a archive in the browser: members with sizes and dates, the symbols each object defines and needs, and whether the symbol index has gone stale.

Developer

Check a JSON document against a JSON Schema in your browser. Every error gets its JSON Pointer, the line it lands on, and the keyword that failed.

Developer

Open a .p7b, .p7s or .p7m in your browser: content type, certificates, CRLs, signers, algorithms and signing times. Nothing is uploaded.

Developer

Open a .p12 or .pfx in your browser: MAC and ciphers before the password, then the certificate chain, the private key, and whether they match.

Developer

Paste a .gitignore and a list of paths to see which are ignored and exactly which line decided — the answer git check-ignore -v gives.

Developer

Paste a .gitattributes and a list of paths to see every attribute git ends up setting on each path, and which line — or which macro — set it.

Developer

Paste a .mailmap and a list of author identities to see what each one resolves to, which entry did it, and which people finally merge into one.

Developer

Paste your git config files and see which value wins for every key, the scope, file and line it came from, what it overrode, and which includeIf fired.

Developer

Inspect a .wasm file in your browser: section sizes, imports and exports with full types, memory pages, the start function, name and producers sections.

Developer

Read a certificate revocation list in your browser: issuer, CRL number, validity window, every revoked serial with its reason, and the signature.

Developer

Decode an OCSP response or request in your browser: status, responder, freshness, nonce, revocation reason and the certificates it carries.

Developer

Work out the git object id of a blob, tree, commit or tag in both SHA-1 and SHA-256, with the header git hashes and the loose object path.

Developer

Read a unified diff or .patch file: files touched, insertions and deletions per file, and the malformed hunks that make git apply fail.

Developer

Read an armored OpenPGP public key: full fingerprint, key ID, algorithm, size, creation and expiry dates, user IDs and subkeys.

Developer

Read a certificate signing request before you send it: subject, SANs, key size, signature algorithm, and whether its self-signature verifies.

Developer

Paste any JSON and get a draft-07 JSON Schema that matches its shape — types inferred, formats detected, required fields filled in.

Developer

Fill out a form, get a ready-to-paste <meta> block — Open Graph for Facebook / LinkedIn / Slack and Twitter Card tags for X / Discord.

Developer

Paste a Cookie: request header or a Set-Cookie: response header and see each cookie's name, value, attributes, and warnings.

Developer

Paste an HTML snippet and get React-ready JSX — class becomes className, onclick becomes onClick, and void tags self-close.

Developer

Convert a URL query string to a JSON object and back, in your browser.

Developer

Build an .editorconfig file with indent style, line endings, charset and common overrides, in your browser.

Developer

Paste an .editorconfig and some file paths: see the property set each file resolves to, and which section on which line decided every value.

Developer

Quick card per HTTP method (GET, POST, PUT, DELETE, PATCH, …) — safety, idempotence, cacheability, and whether request / response bodies are allowed.

Developer

Build a valid manifest.json for a Progressive Web App — name, icons, theme color, display mode, scope — with the matching HTML <link> tags.

Developer

Canonicalize JSON per RFC 8785 and hash it: UTF-16 key order, ECMAScript number form, no whitespace, with a SHA-256 of the exact bytes.

Developer

Apply or generate an RFC 7386 JSON merge patch, with every change listed — including the null that deletes a key rather than setting one.

Developer

Generate an RFC 6902 JSON Patch from a source/target pair, or apply an existing patch to a document. Supports add, remove, replace, move, copy, test ops.

Developer

Paste any DER structure — PEM, base64 or hex — and see its ASN.1 tree: offsets, tags, lengths and decoded values.

Developer

Decode CBOR (RFC 8949) from hex or base64 into readable diagnostic notation — including tags, floats and indefinite-length items. All in your browser.

Developer

Paste base64 or hex MessagePack bytes and read the values — types, nested maps, binary blobs and timestamps — decoded in your browser.

Developer

Paste base64 or hex protobuf bytes and read the fields — numbers, wire types, nested messages, strings and packed arrays — without a schema.

Developer

Parse, compare, and bump semantic versions side-by-side, with a range expander that shows what ^x.y.z and ~x.y.z actually cover.

Developer

Generate live RFC 6238 TOTP codes from a Base32 secret — for testing 2FA flows, debugging authenticator integration, or a temporary fallback.

Developer