All developer tools
Search 110 client-side utilities. Filter by category or jump in with a query.
JSON Formatter
Beautify, minify, sort, and validate JSON entirely in the browser.
JSON → TS
Infer TypeScript interfaces, type aliases, or Zod schemas from sample JSON.
JWT Debugger
Decode JWT header, payload, and signature in-browser with expiry countdown.
cURL → Code
Paste a cURL command and get fetch, Axios, Python requests, and Go http.
Regex Tester
Test JavaScript regular expressions with matches, groups, flags, and replace.
UUID Generator
Bulk-generate UUID v4, UUID v7, NanoID, and high-entropy API keys locally.
SQL Formatter
Pretty-print SQL for PostgreSQL, MySQL, SQLite, MariaDB, and T-SQL.
Base64 / URL
Encode and decode Base64, Base64URL, and URI components, including file data URIs.
Hash Generator
SHA-1, SHA-256, SHA-384, SHA-512, MD5, and HMAC from text or files in-browser.
Unix Timestamp
Convert epoch seconds and milliseconds to ISO time, local time, and time zones.
YAML / TOML
Convert YAML, JSON, and TOML in the browser.
XML ↔ JSON
Convert XML to JSON and run XPath locally.
CSV ↔ JSON
Parse CSV to JSON objects and emit INSERT statements.
JSON Flatten
Flatten nested JSON, rebuild it, and query with JSONPath.
JSON Schema
Validate JSON against a schema and infer a draft from a sample.
JSON Diff
Diff two JSON documents and deep-merge objects locally.
JSONL
Split, join, and sample newline-delimited JSON.
HTML ↔ MD
Convert Markdown to HTML and HTML back to Markdown locally.
.env ↔ JSON
Turn dotenv files into JSON and back.
Tables
Convert HTML tables, CSV, and Markdown tables locally.
ULID / KSUID
Generate time-sortable IDs locally with Web Crypto.
Base32 / 58 / 85
Encode and decode Base32, Base58, and Ascii85 in the browser.
AES-GCM
Encrypt and decrypt with AES-GCM and PBKDF2 in Web Crypto.
TOTP / HOTP
Generate TOTP codes and otpauth URIs locally.
JWT Generator
Sign HS256 tokens locally from a JSON payload.
Passphrase
Generate high-entropy word phrases with Web Crypto.
Check digits
Luhn, Verhoeff, ISBN, and GSTIN format checks.
Redactor
Mask JWTs, PEMs, AWS keys, and password assignments.
PKCE / OAuth
Build S256 PKCE and an authorize URL. No token endpoint is called.
CRC32
CRC-32 of text or file bytes in the browser.
URL tools
Parse URLs, edit UTM params, and slugify paths.
HTTP status
Look up status codes and common headers without leaving the tab.
CORS
See if a browser would allow a cross-origin request.
Cookie builder
Compose Set-Cookie and Cache-Control directives.
Webhook HMAC
Sign and verify Stripe, GitHub, Slack, and Razorpay webhooks locally.
MIME detect
Guess MIME type from magic bytes in the browser.
robots.txt
Generate robots.txt, sitemap.xml, and security.txt stubs.
User-Agent
Parse browser, OS, and device from a User-Agent string.
Case converter
camelCase, snake_case, kebab-case, slugs, and accent folding.
Text diff
Unified diffs and apply patch in the browser.
Line toolkit
Sort, unique, shuffle, reverse, trim, and grep lines locally.
Word counter
Count words, characters, lines, and estimate reading time.
Semver
Parse, bump, compare, and test caret ranges.
gitignore
Combine Node, Python, Go, Rust, Next, and Android ignore templates.
Unicode
Code points, UTF-8 bytes, NFC/NFD, and a punycode hostname peek.
Email syntax
Check email syntax. No SMTP, no mailbox probe.
JSON → INSERT
Turn JSON arrays or CSV into INSERT or PostgreSQL COPY.
Connection string
Parse Postgres, MySQL, Mongo, Redis, and AMQP URLs. Never connects.
Cron
Explain a cron expression and list upcoming fire times.
Time zones
Live times across common IANA zones.
Fake data
Generate fictional people for fixtures. Obviously fake emails.
Lorem
Placeholder paragraphs as text, Markdown, or HTML.
Dummy REST
Users, products, orders, and posts as JSON fixtures.
Dummy webhooks
Sample GitHub, Stripe, Slack, Razorpay, Shopify, and Twilio payloads.
Test cards
Public Stripe, Razorpay, and PayPal test PANs plus Luhn generate.
Dummy files
Build a file of N bytes in memory and download it.
Placeholder
PNG/JPEG/WebP placeholders at any size, in-browser.
QR code
Create a QR from text and decode one from an image.
Color / contrast
HEX, RGB, HSL, and WCAG contrast ratios in the browser.
ZIP
Build a zip or list files inside one. All in memory.
INI / JSON5
Convert INI, .properties, JSON5, and JSONC in the browser.
GraphQL
Pretty-print GraphQL and emit a fetch snippet.
DynamoDB JSON
Convert AttributeValue maps to plain JSON and back.
OpenAPI
Parse OpenAPI JSON or YAML and emit cURL / fetch for the first path.
Hex dump
Dump text or a local file as hex, and decode hex to UTF-8.
RSA / ECDSA
Generate RSA-PSS 2048 or ECDSA P-256 keys and sign locally.
PEM / JWK
Convert PEM and JWK, and emit ssh-rsa from an RSA JWK.
Password KDF
PBKDF2-SHA256, htpasswd {SHA}, and bcrypt in the browser.
Code → cURL
Turn a fetch, Axios, or requests snippet into cURL.
Raw HTTP
Parse a raw request or response and emit fetch.
CSP
Build Content-Security-Policy and related isolation headers.
HTTP composer
Build a raw HTTP request and fetch snippet. Nothing is sent.
Auth headers
Build Authorization: Basic, Bearer, and a Digest example.
Rate limit
Parse Retry-After and X-RateLimit-* headers.
DNS builder
Build A, AAAA, CNAME, MX, TXT, SRV, and CAA records. No live lookup.
SPF / DMARC
Build SPF and DMARC TXT records and a DKIM placeholder. No DNS query.
App links
Build iOS AASA and Android Digital Asset Links files.
CF _headers
Build Cloudflare Pages _headers and _redirects stubs.
AWS SigV4
Build a SigV4 canonical request and optional HMAC signature. No AWS call.
Similarity
Levenshtein, Jaro, and Dice coefficients in the browser.
Phone
Parse and format numbers with libphonenumber-js. No carrier lookup.
Intl
Number, date, relative, list, and plural formatting via Intl.
Line endings
Detect LF, CRLF, CR, convert them, and strip or add a UTF-8 BOM.
ANSI HTML
Turn ANSI color codes into HTML you can preview.
SPDX
Pick a common SPDX id and emit a LICENSE stub.
Commits
Build a Conventional Commits message with type, scope, and breaking.
i18n strings
Convert Android, iOS, gettext, ARB, and JSON string maps.
Excel date
Convert Excel serial numbers to ISO-8601 and back.
ISO duration
Parse P1DT2H-style durations and test interval overlap.
Business days
Add weekdays, count them, and compute an SLO error budget.
OnCalendar
Translate a 5-field cron into a systemd OnCalendar= line.
Dummy logs
Generate JSON, logfmt, Apache, Nginx, or syslog lines.
Dummy CSV
Generate a CSV of fake people for importer tests.
ICS / vCard
Generate a one-event .ics and a simple vCard.
Dummy .env
Node, Next.js, and Docker Compose .env stubs.
India fixtures
Format-check PAN, GSTIN, IFSC, and UPI. Sample values included.
Unicode torture
Zalgo, RTL, ZWJ emoji, homoglyphs, BOM, and long lines for input tests.
problem+json
Build an application/problem+json document.
Identicon
SHA-256 identicon PNG from a seed, drawn on canvas.
Resize
Resize a local image with canvas. PNG, JPEG, or WebP out.
Image convert
Convert a local image between PNG, JPEG, and WebP on canvas.
Markdown preview
Preview Markdown as HTML and extract a table of contents.
Meta tags
Generate title, Open Graph, Twitter card, and WebSite JSON-LD.
CSS units
Convert px and rem, build clamp(), and a modular type scale.
Web manifest
Build a web app manifest.json with icons placeholders.
CIDR
Network, mask, range, host count, and containment for IPv4 CIDR.
gzip
Compress and decompress gzip or deflate with CompressionStream.
Deep links
Android intent URLs, iOS associated-domains stub, and custom schemes.
Money
Format amounts with Intl and a small ISO 4217 catalog.
Log pretty
Pretty-print JSON lines and logfmt into JSON objects.