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Developer Toolkit

Built for Developers by a Developer

Free, fast, and powerful developer tools to accelerate your workflow. Transform URLs, manipulate JSON, generate secure passwords, convert formats, and more - all in your browser.

URL Tools

URL Parser

Break down URLs into component parts for analysis.

URL Builder

Construct URLs with query parameters and fragments.

URL Validator

Check URL format, accessibility and SSL.

URL Redirect Checker

Follow redirects and inspect the full redirect chain with status codes.

JSON Tools

JSON Editor

Edit, format, and validate JSON data.

JSON to Query String

Convert JSON objects to URL query strings.

JSON to TOON

Convert JSON to TOON to save LLM tokens.

TOON to JSON

Convert TOON back to standard JSON.

CSV → JSON

Convert CSV to JSON with header awareness and validation.

JSON → CSV

Convert JSON arrays to CSV with proper quoting.

CSV → XML

Convert CSV rows to XML with proper escaping.

XML → CSV

Convert XML rows to CSV with clean headers.

JSON → YAML

Convert JSON to YAML with validation and pretty printing.

YAML → JSON

Convert YAML to JSON with validation and pretty printing.

Encoding & Decoding Tools

Base64 Encoder

Convert text and files to Base64 format.

Base64 Decoder

Convert Base64 back to original text and files.

URL Encoder

Encode special characters for safe transmission.

URL Decoder

Convert encoded URLs to readable format.

Security & Password Tools

Password Generator

Generate secure passwords with custom options.

Password Checker

Analyze password strength and security.

Hash Generator

Generate MD5, SHA1, SHA256, SHA512 hashes.

Utility Tools

Timestamp Converter

Convert between Unix timestamps and dates.

JWT Decoder

Decode JWT header and payload (Base64URL) and inspect claims.

DNS & WHOIS Lookup

Query DNS records and fetch WHOIS registry data.

API Tester

Send HTTP requests, inspect responses, and debug APIs.

Cron Expression Generator

Convert natural language to cron expression.

Generator Tools

UUID Generator

Generate UUIDs v1, v4, v7 and other versions.

QR Code Generator

Create customizable QR codes from URLs.

Color Palette

Generate beautiful color schemes and palettes.

Text & Content Tools

Text Case Converter

Convert text between different naming conventions.

Lorem Ipsum Generator

Generate placeholder text for design mockups.

Regex Tester

Test and debug regular expressions.

About ThenCatch

ThenCatch is a free developer toolkit built for engineers, designers, and anyone who works with URLs, JSON, APIs, and everyday dev tasks. No sign-up and no paywall — and 29 of our 32 tools run entirely in your browser, so the data you paste in never leaves your device.

We offer 32 utilities: URL parsing and building, Base64 and URL encoding, JSON editing and format conversion (JSON, CSV, YAML, XML), password and hash generators, JWT decoding, cron expression builders, regex testing, QR codes, timestamps, and more. Each tool is designed to be fast and focused so you can get back to coding.

ThenCatch is built and maintained by 11Vertex, a product engineering studio. These are the tools we reach for in our own client work, so we keep them fast, accurate, and free. Advertising covers the hosting bill and never gates a tool. Learn more about us, or get in touch with feedback or tool requests.