Free Developer Tools That Run in Your Browser

Format JSON, test regex, inspect JWTs, and plan cron schedules locally. Your input stays in your browser, with clear engine details and no account required.

See our engines, checks, and known limitations

JSON Formatter & Validator

Format, pretty print, minify, and validate JSON documents with exact line and column syntax error pointers.

 Cron Expression Editor & Tester

Parse, validate, and inspect cron expressions with Unix and a supported Quartz/AWS subset, IANA timezone matching, and upcoming runs.

 JSON ↔ YAML ↔ CSV Converter

Bidirectional conversion between JSON, YAML, and CSV formats powered by locally bundled js-yaml.

 JavaScript Regex Tester

Test JavaScript regular expressions with live match highlighting, capture groups, named groups, replacement preview, and ECMAScript flags.

 Base64 & Base64URL Encoder / Decoder

Encode and decode Base64 and URL-safe Base64URL strings with full UTF-8 Unicode support via native TextEncoder/TextDecoder.

 JWT Decoder & Inspector

Decode JSON Web Token header and payload, inspect standard claims, and check expiry status. Client-side decoding only — signature not verified.

 UUID Generator (v4 & v7)

Generate cryptographically random UUID v4 and time-ordered UUID v7 identifiers using browser Web Crypto.

 Unix Timestamp Converter

Convert between Unix epoch timestamps (seconds/milliseconds), ISO 8601, and human-readable UTC and local time.

 Hash Generator (SHA-256, 384, 512)

Generate SHA-256, SHA-384, SHA-512, and legacy SHA-1 cryptographic digests of text or local files using Web Crypto.

 Color Converter & Contrast Checker

Convert colors between HEX, RGB, and HSL formats with live preview swatch, CSS variable generation, and WCAG contrast check.

 URL Encoder / Parser

Encode and decode URI components and parse full URLs into protocol, hostname, path, query parameters table, and fragment.

 JSON Diff & Comparison

Compare two JSON documents structurally with color-coded key additions, removals, modifications, and deep JSON path tracking.

 Text Diff & Comparison

Side-by-side and unified text diff viewer with line-level and word-level change highlighting, additions, and deletions.

 JSON → TypeScript Generator

Generate clean, idiomatic TypeScript interface and type definitions from JSON data with nested types and nullable inference.

 JSON Schema Validator

Validate JSON payloads against JSON Schema specifications with exact error paths, keyword mismatches, and schema diagnostics.

 CIDR & Subnet Calculator

Calculate IPv4 network address, broadcast address, netmask, wildcard mask, first and last usable host IP addresses, and CIDR prefix.

FAQ

About the Tools

Is my data safe? Does anything leave my browser?

Your tool input never leaves your device. Every tool runs entirely in client-side JavaScript. No input is sent to QuikTech or included in analytics. If you choose to copy a share link on Cron, Regex, or Color, anyone you send it to can read the included settings. Regex test text is excluded unless you opt in.

Local storage: Some tools remember your recent input in your browser's localStorage so you can pick up where you left off. This data never leaves your device. Sensitive tools (JWT Decoder) never save input locally. You can clear saved data at any time through your browser settings or the privacy controls on each tool page.

The site uses Google Analytics 4 to track page visits (not content). Analytics only runs with your consent. See the Privacy Policy for full details.

Does QuikTech work offline?

Yes — after the offline cache finishes installing, tool pages, scripts, and fonts are available without a network connection. Your first visit needs a connection.

Google Analytics will fail silently when offline — this does not affect tool functionality.

Cron Expression Editor

What it does: Calculates upcoming runs in your selected timezone for Unix cron and a documented subset of Quartz and AWS syntax.

⚠ Results reflect standard Unix cron semantics. systemd timers, AWS EventBridge, Quartz Scheduler, and other platforms have their own variations — always verify in your target environment before deploying.

JSON Formatter / YAML Converter

What it does: Formats, validates, and converts data between JSON, YAML, and CSV. YAML support is powered by the bundled js-yaml 4.1.0 library — no CDN required.

⚠ CSV conversion assumes a flat structure (array of objects with scalar values). Nested objects or arrays will be stringified. Round-tripping through CSV may lose type information.

Regex Tester

What it does: Tests a regular expression against sample text, highlights every match inline, lists capture groups and named groups with positions and values, and previews replacements.

⚠ Uses the JavaScript RegExp engine. Patterns from Python re, PCRE (PHP/Perl), or Go regexp may behave differently — especially around lookaheads, named groups, and backreferences.

JWT Decoder

What it does: Splits a JSON Web Token into its three parts and decodes the header and payload. Standard claims (exp, iat, nbf, sub, iss, aud) are shown in human-readable form.

⚠ This tool does not verify the signature. A decoded token is not a validated token. JWT input is never saved to browser storage. Do not paste real production or session tokens into any online tool.

Base64 Encode / Decode

What it does: Converts text to Base64 or Base64URL, or decodes them back. Unicode input is handled correctly via TextEncoder/TextDecoder.

⚠ Base64 is encoding, not encryption. Anyone who sees the encoded string can decode it instantly. Never use Base64 to conceal sensitive data.

UUID Generator

What it does: Generates UUID v4 (cryptographically random) and UUID v7 (time-ordered, sortable) identifiers using the browser's secure random number generator.

⚠ UUIDs are collision-resistant identifiers — they are not secret keys or passwords. Do not use a UUID as an API token or cryptographic secret.

Hash Generator

What it does: Produces SHA-256, SHA-384, SHA-512 hex digests of text or files, using the browser's built-in crypto.subtle.digest() API. SHA-1 is available as a legacy option.

⚠ Do not use these for passwords. SHA-256 is fast by design, making it trivial to brute-force. Use bcrypt, Argon2, or scrypt for password storage.

Timestamp Converter

What it does: Converts between Unix timestamps (seconds and milliseconds), ISO 8601 date-time strings, and human-readable local/UTC time. Automatically detects whether input is seconds or milliseconds.

Color Converter

What it does: Converts colors between HEX, RGB, and HSL formats with a live swatch and WCAG contrast ratio check for foreground/background pairs.

URL Encoder / Parser

What it does: Applies percent-encoding (encodeURIComponent) to a string, or decodes percent-encoded sequences. Also parses full URLs into protocol, hostname, port, pathname, query parameters, and fragment.

⚠ encodeURIComponent encodes everything except letters, digits, and - _ . ! ~ * ' ( ). encodeURI preserves URL structure characters. Choose the right one for your use case.