Most browser tools send your data to a server. These don't.
Browser-based utility tools for developers, hardware diagnostics, and security work.
Everything runs client-side. No uploads, no accounts.
| Tool | Description |
|---|---|
| Monitor & Display Test Suite | Dead pixel patterns, backlight bleed, motion ghosting, fullscreen test modes |
| Input Lag & Mouse Polling Rate Tester | Browser input latency and mouse polling rate via PointerEvent API |
| Webcam A/V Sync & Latency Meter | Millisecond offset between webcam and microphone, OBS-ready output |
| Webcam Lighting & Framing Analyzer | Lighting balance, face framing, and resolution diagnostics |
| Web MIDI Keyboard & Latency Tester | Dead keys, ghost notes, and USB-to-browser MIDI input latency |
| Gamepad & Joystick Drift Tester | Analog stick drift, dead zone visualization, button diagnostics |
| Live Signal Debugger (coming) | Real-time USB/Serial/Bluetooth signals from Arduino, sensors, MIDI controllers |
| WebUSB Hardware Flasher (coming) | Flash firmware to ESP32, Arduino, and Raspberry Pi Pico in-browser |
| Tool | Description |
|---|---|
| JWT Decoder | Inspect header, payload, and expiry of any JWT token |
| Base64 Encoder / Decoder | Encode and decode text or files to Base64 |
| Hash Generator | MD5, SHA-1, SHA-256, SHA-512, and HMAC computation |
| Cron Expression Parser | Translate cron syntax to plain English with next-run preview |
| SQL Data Workbench | Query local files with SQL: Parquet, Arrow, Feather, Avro, DBF, Excel, CSV, JSON |
| Big Log Explorer | Filter, search, and graph 500 MB+ log and JSONL files via Web Workers and IndexedDB |
| Prompt Token Counter | Token count and context window usage for GPT-4o, Claude, and Gemini models |
| JSON Formatter & Validator (coming) | Pretty-print, minify, and validate JSON with syntax highlighting |
| Regex Tester (coming) | Live match highlighting and group capture view |
| UUID Generator (coming) | Cryptographically random UUID v4 with bulk export |
| Text / Code Diff Viewer (coming) | Side-by-side and unified diff with line-level highlighting |
| Binary Package Differ (coming) | Diff two ZIP archives or build artifacts: file tree, size delta, byte-level changes |
| WASM Binary Inspector (coming) | Decompile WebAssembly to WAT, memory map, exports and imports |
| Tool | Description |
|---|---|
| Browser Fingerprint Inspector | Canvas hash, WebGL renderer, audio fingerprint, fonts, and 30+ leak signals |
| PII Scrubber | Detect and tokenize PII, secrets, and internal data before sending to AI |
| EXIF & Image Metadata Scrubber | Strip GPS coordinates, timestamps, and device data from images |
| Offline OCR & Document Redactor | Extract text and redact sensitive regions via Tesseract WASM |
| X.509 Certificate Inspector | Validity, SANs, key algorithm, chain depth, and expiry from PEM or DER input |
| Cloud Config Sanitizer | Validate Kubernetes, Terraform, and YAML manifests, detect secrets and security smells |
| File Hash Verifier | SHA-256, SHA-512, SHA-1, and MD5 checksums compared against a published hash |
| Password Entropy Analyser (coming) | Bits of entropy and estimated crack time |
| URL Encoder / Decoder (coming) | Percent-encode and decode URLs and query strings with component parsing |
| Quantum-Safe Encryptor (coming) | Post-quantum encryption and decryption via Kyber/Dilithium WASM |
| Build Integrity Verifier (coming) | SHA-256 and BLAKE3 artifact comparison with functional content diff |
| Local Secret Scanner (coming) | Scan code, configs, and ZIP archives for API keys, tokens, and credentials |
| Tool | Description |
|---|---|
| Speaker Frequency Sweep & Resonance Tester | 20 Hz to 20 kHz sweep to find resonances, rattle points, and drop-off frequencies |
| Microphone Quality, Noise & Latency Tester | Noise floor, clipping, frequency response, echo loopback, and round-trip latency |
| Decibel Calculator | Convert between dB, watts, volts, and SPL with formula reference |
| Tool | Description |
|---|---|
| Ohm's Law Calculator | Solve for voltage, current, resistance, or power from any two values |
| Resistor Colour Code Calculator | 4-band, 5-band, and 6-band decoding with tolerance, temperature coefficient, E-series |
| Engineering Unit Converter | SI and imperial units across 17 physical dimensions |
| Electricity Unit Converter | Charge, current, voltage, resistance, capacitance, inductance across 15 dimensions |
| Aspect Ratio Calculator | Display resolutions, scaling, and letterbox bars for any ratio |
| Tool | Description |
|---|---|
| Readability Analyser | Flesch-Kincaid Grade, Flesch Reading Ease, and SMOG with sentence-level highlights |
| Case Converter | camelCase, snake_case, SCREAMING_SNAKE, kebab-case, Title Case, PascalCase |
| Reading Time Calculator (coming) | Reading time estimate at adjustable WPM targets |
| Markdown Preview (coming) | Live-render Markdown with clean typeset output and copy-as-HTML export |
| Tool | Description |
|---|---|
| Color Format Converter | Convert between HEX, RGB, HSL, HSV, OKLCH, and CSS named colours |
| WCAG Contrast Checker (coming) | AA and AAA contrast ratio testing with hex, RGB, and HSL input |
| CSS Gradient Builder (coming) | Visual linear and radial gradient editor with live CSS output |
| Tool | Description |
|---|---|
| IPv4 / IPv6 Subnet & CIDR Calculator | Network ranges, broadcast addresses, and host counts for IPv4 and IPv6 |
| URL Parser & Inspector | Decompose any URL into protocol, host, path, query params, and fragment |
| HTTP Status Code Reference | Searchable reference for all HTTP 1xx to 5xx codes with usage notes |
| P2P Network Tester | WebRTC peer-to-peer latency, jitter, and packet loss between two browsers |
| IndexNow URL Submitter | Submit URLs to Bing, Yandex, Naver, and more via IndexNow |
| MIME Type Reference (coming) | Searchable MIME database with extension mapping and RFC sources |
- Headphone Buying Guide: How to Test Frequency Response, Channel Balance, and Latency Before You Commit
- Hash Functions in the Browser: How to Use CapyToolkit's Client-Side Hash Generator for Integrity Checks and HMAC Signatures
- Gaming Peripheral Specs You Can Verify in the Mouse, Controller, and Webcam
- Base64 Encoding Without the Cloud: What Your Browser Handles Locally
- Submitting URLs to Search Engines via IndexNow Without a CMS Plugin
- Achieving Perfect Audio-Video Sync in OBS Streams Using CapyToolkit's Webcam A/V Sync & Latency Meter
Built with Astro and TypeScript. Installable as a PWA.