Developer Guides
27 guides in this category
Markdown to HTML Live Preview
Preview Markdown rendering before publishing to GitHub, a static site, or your CMS.
SQL Formatter Pretty Print
Formatted SQL is easier to review in pull requests, documentation, and debugging sessions.
Cron Expression Every 5 Minutes
The cron expression */5 * * * * runs a job every 5 minutes. Use our generator for other schedules too.
JSON Formatter vs Validator
Formatting makes JSON readable; validation checks if it is syntactically correct. You often need both.
What Is a Unix Timestamp
APIs and databases often store dates as Unix time a single integer counting seconds (or milliseconds) from the epoch.
robots.txt for Next.js
Next.js can serve robots.txt from app/robots.ts or public/robots.txt. Our generator helps you draft rules quickly.
Diff Checker for Code
Before committing, compare two versions of config, JSON, or source code to see exactly what changed.
JWT Generator for Testing
When building APIs, you need sample JWTs to test auth middleware. Generate HS256 tokens without a backend script.
Create Favicon for Next.js
Next.js 13+ supports app/icon.png and app/favicon.ico. Generate a full icon set from your logo in the browser.
SHA256 vs bcrypt for Passwords
SHA256 is fast which makes it wrong for password storage. bcrypt is slow by design to resist brute force.
HEX to RGB for CSS
Design tools export HEX; CSS often needs rgb() or rgba(). Convert instantly with a color swatch preview.
Bulk UUID for Database Seeding
Seeding test databases with realistic IDs is tedious. Generate up to 1000 UUIDs and copy or download as .txt.
bcrypt Work Factor Explained
bcrypt's slowness is a feature. The work factor (rounds) controls how expensive hashing is for attackers.
htaccess 301 Redirect Generator
Permanent moves, HTTPS upgrades, and www canonicalization are standard SEO tasks get correct RewriteRule syntax fast.
XML Sitemap for Small Websites
Search engines discover pages faster with a sitemap. Paste your URLs and download XML ready for /sitemap.xml.
JSON Formatter Pretty Print
Minified JSON from APIs is hard to read. Format with indentation and spot syntax errors before they reach production.
JSON Validator Online
Before deploying configs or API payloads, confirm your JSON is valid. Get human-readable error messages instantly.
Base64 Encode and Decode
Base64 represents binary data as ASCII text common in JWT payloads, data URLs, and API responses.
URL Encoder and Decoder
Special characters in URLs must be percent-encoded. Encode user input before building query strings safely.
Regex Tester Online
Regular expressions are powerful but easy to get wrong. Test patterns against sample text before shipping code.
JWT Decoder for Debugging
JWTs are three Base64URL segments. Paste a token to inspect claims never paste production secrets in untrusted tools.
HTML Minifier Online
Smaller HTML improves load time slightly and is useful for embedded snippets and email templates.
UUID v4 Generator
UUID v4 IDs are standard for primary keys and correlation IDs in distributed systems.
Unix Timestamp Converter
Logs and APIs use Unix seconds or milliseconds. Convert instantly for debugging and support tickets.
Cron Expression Parser
Cron syntax is compact but cryptic. See the next run times and a plain-language description before deploying jobs.
Essential Developer Tools
Daily development needs small utilities: format JSON, test regex, decode JWT, generate cron. ToolKits runs them client-side.
Color Picker HEX and RGB
Design in the browser and copy values straight into your stylesheet or design tokens file.