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Developer tools that never send your data anywhere

Everything is processed in your browser. Every tool comes with a guide to learn.

  • No uploads: your data never leaves the browser
  • Works offline
  • Guides in English and Spanish
  • Learning paths

Encoding

2 tools

Base64

Encode and decode text and files as Base64 and Base64URL.

URL

Encode, decode and parse URLs and query parameters.

Security

4 tools

CSP and security headers

Build a Content-Security-Policy, review its flaws and export the headers for nginx, Apache, Netlify or Caddy.

Hash / HMAC

Compute SHA-256, SHA-512 and HMAC of a text or file, and compare with an expected hash.

JWT

Decode, verify and create JSON Web Tokens with security warnings.

PEM / X.509

Decode PEM certificates, CSRs and public keys: subject, validity, SAN, fingerprints and ASN.1 tree.

Formatters

2 tools

Formatters

Format and validate JSON, YAML, XML, SQL, HTML, CSS and JavaScript.

JSONPath

Query JSON with JSONPath expressions: filters, slices and recursive descent, with the path of every match.

Converters

6 tools

JSON ⇄ YAML ⇄ CSV

Convert data between JSON, YAML and CSV, with automatic detection of the input format.

Cron

Explain a cron expression in plain language and compute its next runs.

cURL to code

Convert a cURL command into fetch, axios or Python requests code.

Epoch / Dates

Convert Unix timestamps to readable dates (and back) in any time zone.

JSON to TypeScript

Generate TypeScript interfaces or types from a sample JSON, with nesting and optional fields.

Number Base

Convert numbers between binary, octal, decimal and hexadecimal, with BigInt support, bits and endianness.

Web design

7 tools

CSS buttons

Design buttons (solid, outline, ghost, gradient) with all their states and copy the HTML and CSS.

Color and contrast

Convert colors between HEX, RGB and HSL, build a shade scale and check WCAG contrast.

CSS Units

Convert between px, rem, em, pt, vw, vh and more, using the font size and viewport you choose.

Fluid type and rem

Generate clamp() for sizes that grow with the screen and convert between px, rem and em.

CSS gradients

Build linear, radial and conic gradients with a live preview and copy the CSS or Tailwind class.

Border radius and shapes

Design rounded corners, circles and organic shapes with border-radius and copy the CSS.

CSS shadows

Design multi-layer box-shadow with a live preview and copy the CSS or Tailwind class.

APIs

2 tools

Swagger / OpenAPI

View OpenAPI 3 and Swagger 2 documents (YAML or JSON) without sending them to any server.

User-Agent Parser

Break a User-Agent string into browser, engine, operating system and device, and detect bots.

Generators

3 tools

Passwords

Generate secure random passwords and check the strength of an existing one, without sending it anywhere.

QR

Generate QR codes for text, URLs, WiFi and contacts; download them as SVG or PNG.

UUID / ULID / KSUID

Generate UUID v4 and v7, ULID, KSUID and NanoID, and inspect the version and date of a UUID.

Text

3 tools

Diff

Compare two texts or JSON line by line and highlight the words that changed.

Regex

Test regular expressions with highlighting, capture groups and protection against patterns that hang.

Text transformer

Change letter case, convert to camelCase or snake_case, put text on one line, minify it or escape it as a JSON string.