Programming tools: encoders, formatters, generators

Format JSON, decode JWTs, encode base64, hash strings, test regex - all the dev utilities, none of the ads.

A curated hub for developers. Format and lint JSON / YAML / XML / SQL, encode and decode base64 / URL / HTML entities, hash strings with SHA-1 / SHA-256 / SHA-384 / SHA-512, decode and inspect JWTs, build and test regular expressions, generate UUIDs and mock data, convert between number bases or roman numerals, build Markdown tables, minify HTML and read cron expressions. Everything runs in your browser - no signup, no ads, no upload.

Encoding & hashing

Base64 Encoder / Decoder

Encode and decode Base64 strings (text and files).

URL Encoder / Decoder

Percent-encode and decode URLs and query strings.

Hash Generator (SHA-1, SHA-256, SHA-384, SHA-512)

Compute cryptographic hashes of text in your browser.

JWT Decoder

Decode and inspect JSON Web Tokens locally.

HTML Entity Encoder / Decoder

Encode and decode HTML entities, named and numeric.

Data formats

JSON Formatter & Validator

Format, minify and validate JSON instantly.

YAML to JSON Converter

Convert YAML to JSON and back, in your browser.

CSV to JSON Converter

Convert CSV to JSON and back, with custom delimiter.

XML Formatter

Pretty-print or minify XML with proper indentation - in your browser, no upload.

SQL Formatter

Pretty-print SQL with consistent keyword casing and line breaks.

Markdown & HTML

Markdown to HTML Converter

Convert Markdown to HTML and back, with a live preview.

Markdown Table Generator

Build a Markdown table from rows and columns with column alignment - or paste CSV / TSV and get the table back.

HTML Minifier

Strip whitespace, comments and quotes from HTML - in your browser, with a before/after size report.

Regex & number systems

Regex Tester

Test and debug regular expressions with live highlights.

Number Base Converter

Convert numbers between binary, octal, decimal and hexadecimal.

Roman Numeral Converter

Convert decimal numbers to Roman numerals and back.

Generators & utilities

UUID Generator

Generate v4 (random) and v7 (time-sorted) UUIDs in bulk.

Mock Data Generator

Generate fake user records - name, email, phone, address - as JSON or CSV. No signup, no API call.

Cron Expression Reader

Decode a cron expression into plain English plus the next 5 run times.

Username Generator

Generate random usernames - adjective + noun + number, or pick a theme. All client-side.

Free programming tools: JSON formatter, JWT decoder, regex tester and more

Every developer accumulates a small set of websites they reach for daily: a JSON formatter for the response from an API they're debugging, a JWT decoder for the token they're investigating, a base64 codec for an obscure auth header, a regex tester for the pattern they're trying to land. This hub puts those in one place: a JSON formatter with minify and pretty-print, a YAML / JSON / CSV converter, a SQL formatter with case-aware keyword handling, an XML formatter and minifier, JWT decoder that splits header / payload / signature and decodes the claims, base64 encode/decode in both directions, URL encode/decode, HTML-entity encode/decode, hash generator for SHA-1 / 256 / 384 / 512, regex tester with live match highlighting, UUID v4 generator, and a cron expression reader that translates cron strings to plain English.

On the generation side: a mock-data generator that emits JSON / CSV / SQL inserts ready for seeding a database, a Markdown-table generator with column alignment, a username generator with themed wordlists, a number-base converter (binary / octal / decimal / hex), a roman-numeral converter, and a Markdown-to-HTML round-trip tool. Each runs entirely client-side; the payload you paste in stays in your browser, which is the right default for hashing tokens and decoding JWTs that contain user data.

All tools are free, no signup, no ads, with full localisation across English, French, Spanish, German and Portuguese. Pages load in under a second and have proper JSON-LD markup so Google can surface them as direct answers when you search for `jwt decoder`, `json formatter` or `regex tester`.