Developer Tools

A toolkit of free developer utilities that run entirely in your browser — format and validate JSON, encode and decode Base64, decode JWTs, test regular expressions, generate UUIDs, and convert between data formats, with nothing ever sent to a server.

Transform structured data

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JSON Formatter & Validator

Pretty-print, minify and validate JSON, with inline error messages.

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CSV ⇄ JSON Converter

Convert CSV to a JSON array and JSON back to CSV.

JSON to TypeScript

Generate TypeScript interfaces from a JSON sample, inferring types recursively.

⊞}

JSON Flatten / Unflatten

Flatten nested JSON to dot-notation keys, or rebuild nested objects from flat keys.

A↓}

JSON Key Sorter

Recursively sort the keys of a JSON object, ascending or descending.

JSON to XML

Convert a JSON object into an indented XML document.

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JSON Diff

Compare two JSON objects and list every added, removed and changed value by path.

Y⇄

YAML ⇄ JSON Converter

Convert YAML to JSON and JSON to YAML with validation errors, multi-document support and indent options.

T⇄

TOML ⇄ JSON Converter

Convert TOML config files to JSON and JSON back to TOML with clear syntax error reporting.

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JSON to Go Struct

Convert a JSON sample into typed Go structs with json tags. Infers int64, float64, bool, nested structs and slices in your browser.

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XML to JSON Converter

Convert XML to JSON and back in your browser, preserving attributes, text nodes and repeated elements.

Format and minify code

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XML Formatter

Pretty-print XML with indentation or minify it down to a single line.

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SQL Formatter

Format SQL by uppercasing keywords and putting clauses on their own lines.

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HTML Minifier

Minify HTML by removing comments and collapsing extra whitespace.

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CSS Minifier

Minify CSS by stripping comments and unnecessary whitespace.

{ }

CSS Beautifier

Format and indent minified CSS with proper newlines and spacing.

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JavaScript Beautifier / Formatter

Paste JavaScript or open a UTF-8 .js or .mjs file, then choose Format or Minify. JavaScript syntax is supported; TypeScript and JSX are not.

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JavaScript Minifier

Paste JavaScript or open a UTF-8 .js or .mjs file, then choose Format or Minify. JavaScript syntax is supported; TypeScript and JSX are not.

Encode and inspect data

Base64 Encoder / Decoder

Encode text to Base64 or decode it back — full UTF-8 support.

HTML Entity Encoder

Encode text to HTML entities or decode entities back to text.

JSON String Escaper

Escape or unescape a string for safe use inside a JSON document.

Backslash Escaper

Escape or unescape backslash sequences such as \n, \t and \uXXXX.

Base45 Encoder/Decoder

Encode and decode Base45 as defined by RFC 9285, used in EU COVID QR codes.

Punycode / IDN Converter

Convert international domain names to Punycode (xn--) ASCII and back to Unicode.

NFC

Unicode Normalizer

Normalize Unicode text using the NFC, NFD, NFKC or NFKD forms.

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Ascii85 / Base85 Encode & Decode

Encode bytes to Ascii85/Base85 and decode them back, supporting the standard and Adobe (<~ ~>) variants, entirely in your browser.

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Base62 Encode & Decode

Convert integers or byte strings to and from compact URL-safe Base62 (0-9A-Za-z), with BigInt support and a GMP alphabet variant, all in-browser.

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Source-Code String Escaper / Unescaper

Escape or unescape text as a string literal for Java, C#, C/C++, JavaScript, JSON, SQL, or XML/HTML — one tool, seven languages, all in-browser.

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Unicode Character Inspector

Break any string into code points and show each one's U+ hex, category, block, UTF-8/UTF-16 bytes, HTML entity, JS escape, percent-encoding, and flags.

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Quoted-Printable Encode & Decode

Encode text to or decode text from MIME Quoted-Printable (=XX escapes, soft line breaks), with a body mode and the RFC 2047 header 'Q' variant.

Binary & Hex Calculator

Add, subtract, multiply, divide or bit-shift and combine numbers in binary, octal, decimal and hex with exact BigInt math.

Inspect URLs and web requests

URL Encoder / Decoder

Percent-encode strings for safe use in URLs, or decode them back.

Query String Parser

Parse a URL query string into JSON and convert JSON back into a query string.

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URL Parser

Break a URL into its protocol, host, port, path, query and hash parts.

User-Agent Parser

Identify the browser, rendering engine and operating system from a user-agent string.

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Keyboard Event Tester

See the key, code and keyCode for any key you press, with modifier flags.

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HTTP Status Codes

Look up the name and meaning of any HTTP status code by number or text.

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cURL to Code Converter

Paste a curl command and get an equivalent JavaScript fetch() snippet — method, headers, body and auth.

Inspect hashes and security data

Hash Generator

Generate SHA-1, SHA-256, SHA-384 and SHA-512 hashes of any text.

JWT

JWT Decoder

Decode a JSON Web Token's header and payload locally — no verification.

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File Checksum (WASM)

Compute CRC-32, Adler-32 and SHA-256 of any file — powered by WebAssembly.

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.htpasswd Generator

Create Apache/nginx .htpasswd lines with salted APR1-MD5 or SHA-1 hashes, fully offline in your browser.

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X.509 Certificate Decoder

Decode a PEM or DER X.509 / TLS certificate in your browser: subject, issuer, validity, serial, public key, SANs, key usage, and SHA-1/256 fingerprints.

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URL / IP Defanger & Refanger

Defang or refang URLs, domains, IPs, and emails (http→hxxp, .→[.], @→[at]) so malicious indicators can be shared safely without becoming clickable.

Generate and inspect identifiers

ULID

ULID Generator

Generate sortable, lexicographically ordered, unique ULID identifiers.

nano

Nano ID Generator

Generate compact, URL-safe, unique IDs with a custom size and alphabet.

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Snowflake ID Decoder

Decode a Twitter or Discord snowflake ID into its timestamp, worker, process and sequence.

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IBAN Validator & Parser

Validate an International Bank Account Number offline with the MOD-97 checksum and break it into country, check digits, bank code, branch, and account.

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BIC / SWIFT Code Validator & Parser

Validate a BIC/SWIFT code against the ISO 9362 format and break it into bank, country, location, and branch segments — with test/passive flags.