# CapyToolkit

Access a growing collection of free browser utilities for hardware testing, dev work, audio, security, and personal files. 100% client-side. Zero uploads. Try them now.

## Sitemaps

[XML Sitemap](https://capytoolkit.com/sitemap_index.xml): Includes all crawlable and indexable pages.

## Main Pages

[CapyToolkit](https://capytoolkit.com/): A growing collection of browser-based utility tools for developers, creators, and power users. All tools run client-side - nothing you input is ever transmitted.
[About](https://capytoolkit.com/about/): Learn about CapyToolkit and the browser-based utility tools it provides.
[Contact](https://capytoolkit.com/contact/): Get in touch with the CapyToolkit team.
[Privacy Policy](https://capytoolkit.com/privacy-policy/): How CapyToolkit handles your data. All tools run entirely in your browser - no uploads, no accounts, no server processing.
[Terms of Use](https://capytoolkit.com/terms-of-use/): Terms governing your use of CapyToolkit and its browser-based utility tools.
[Changelog](https://capytoolkit.com/changelog/): A history of CapyToolkit updates including new tool releases, feature enhancements, and bug fixes.

## Tools

### Tool Categories

[Hardware & Display Diagnostics](https://capytoolkit.com/tools/hardware/): Run physical-world hardware and display tests directly in your browser. Verify monitor pixels, webcam lighting, and input lag locally. Start testing now.
[Developer Parsers & Encoders](https://capytoolkit.com/tools/developer/): Format, encode, parse, and inspect developer data entirely client-side. Protect sensitive code and tokens with these secure, zero-upload dev tools.
[Text Analysis Tools & Converters](https://capytoolkit.com/tools/text/): Analyze readability, convert case formats, and perform text diffs natively in your browser. Ensure absolute privacy with offline-capable text utilities.
[Audio & Acoustic Testing Tools](https://capytoolkit.com/tools/audio/): Measure, sweep, and stress-test your audio hardware securely. Leverage the Web Audio API for precise, local microphone and speaker diagnostics in the browser.
[Math & Engineering Calculators](https://capytoolkit.com/tools/math/): Solve complex equations with free calculators for electronics, signal theory, and unit conversions. Get instant, local results without creating an account.
[Security & Privacy Tools](https://capytoolkit.com/tools/security/): Hash files, encode credentials, and scrub metadata entirely client-side. Protect sensitive information with fast, reliable, privacy-first tools.
[Web Design Utilities & CSS Tools](https://capytoolkit.com/tools/design/): Generate CSS, check contrast, and convert color palettes instantly. Streamline workflows with free, browser-native design tools.
[Network & Web Reference Tools](https://capytoolkit.com/tools/network/): Inspect URLs, HTTP headers, and IP subnets instantly in your browser. Ensure data privacy with offline-capable network utilities requiring no account.
[Personal Tools](https://capytoolkit.com/tools/personal/): Passport photos, PDFs, and everyday calculators that run on this device. Nothing uploaded.

### Tool Pages

[Dead Pixel & Flicker Test Suite](https://capytoolkit.com/tools/hardware/monitor-test/): Backlight bleed, motion ghosting, and color banding checks, tested fullscreen and entirely client-side. See more: [resources](https://capytoolkit.com/tools/hardware/monitor-test/llms.txt)
[Mouse Polling Rate & Input Lag Tester](https://capytoolkit.com/tools/hardware/input-lag/): Verify your mouse polling rate and browser input latency. PointerEvent-based, 100% local. See more: [resources](https://capytoolkit.com/tools/hardware/input-lag/llms.txt)
[Webcam A/V Sync & Latency Meter](https://capytoolkit.com/tools/hardware/webcam-latency/): Measure the millisecond offset between your webcam and microphone — paste the result directly into OBS. See more: [resources](https://capytoolkit.com/tools/hardware/webcam-latency/llms.txt)
[Webcam Lighting & Framing Analyzer](https://capytoolkit.com/tools/hardware/webcam-test/): Lighting balance, face framing, and resolution diagnostics — 100% local, nothing uploaded. See more: [resources](https://capytoolkit.com/tools/hardware/webcam-test/llms.txt)
[Web MIDI Keyboard Latency Tester](https://capytoolkit.com/tools/hardware/midi-test/): Test MIDI keyboards for dead keys, ghost notes, and USB-to-browser input latency — 100% local, no DAW required. See more: [resources](https://capytoolkit.com/tools/hardware/midi-test/llms.txt)
[Gamepad & Joystick Drift Tester](https://capytoolkit.com/tools/hardware/gamepad-test/): Diagnose analog stick drift and dead buttons in your browser. See more: [resources](https://capytoolkit.com/tools/hardware/gamepad-test/llms.txt)
[JSON Formatter, Validator & Tree Viewer](https://capytoolkit.com/tools/developer/json-formatter/): Pretty-print, minify, and browse JSON in a collapsible tree with syntax highlighting. See more: [resources](https://capytoolkit.com/tools/developer/json-formatter/llms.txt)
[Regex Tester & Match Debugger](https://capytoolkit.com/tools/developer/regex-tester/): Live match highlighting, capture groups, and step-through debugging for any pattern. See more: [resources](https://capytoolkit.com/tools/developer/regex-tester/llms.txt)
[Base64 Text & File Encoder/Decoder](https://capytoolkit.com/tools/developer/base64/): Converts between raw data and Base64 entirely client-side, so nothing ever leaves your browser. See more: [resources](https://capytoolkit.com/tools/developer/base64/llms.txt)
[Hash Generator: MD5, SHA-1, SHA-256 & SHA-512](https://capytoolkit.com/tools/developer/hash-generator/): MD5, SHA-1, SHA-256, SHA-512 hashes and HMAC — all computed locally, nothing uploaded. See more: [resources](https://capytoolkit.com/tools/developer/hash-generator/llms.txt)
[UUID v1, v4 & v7 Generator](https://capytoolkit.com/tools/developer/uuid-generator/): Five display formats, cryptographically random output, and 100% local generation. See more: [resources](https://capytoolkit.com/tools/developer/uuid-generator/llms.txt)
[JWT Decoder & Claims Inspector](https://capytoolkit.com/tools/developer/jwt-decoder/): Decode the header and payload, check expiry and claims, all client-side. See more: [resources](https://capytoolkit.com/tools/developer/jwt-decoder/llms.txt)
[Cron Expression Parser & Next-Run Preview](https://capytoolkit.com/tools/developer/cron-parser/): Translate cron syntax into plain English and see upcoming run times at a glance. See more: [resources](https://capytoolkit.com/tools/developer/cron-parser/llms.txt)
[SQL Data Workbench](https://capytoolkit.com/tools/developer/sql-workbench/): Query local files with SQL — Parquet, Arrow, Feather, Avro, DBF, Excel, CSV, JSON and more. Zero upload, runs entirely in your browser. See more: [resources](https://capytoolkit.com/tools/developer/sql-workbench/llms.txt)
[Big Log Explorer](https://capytoolkit.com/tools/developer/log-explorer/): Filter, search, and graph 500 MB+ log and JSONL files locally — Web Workers and IndexedDB, nothing uploaded. See more: [resources](https://capytoolkit.com/tools/developer/log-explorer/llms.txt)
[Prompt Token Counter](https://capytoolkit.com/tools/developer/token-counter/): Count tokens for GPT-5.6, Claude Opus 5, Gemini 3.6, Kimi K3, and 33+ more AI models — live pricing updated daily, nothing leaves your browser. See more: [resources](https://capytoolkit.com/tools/developer/token-counter/llms.txt)
[Flesch-Kincaid & SMOG Readability Scorer](https://capytoolkit.com/tools/text/readability-score/): Sentence-level highlights show exactly which lines drag your grade level down, all client-side with no account required. See more: [resources](https://capytoolkit.com/tools/text/readability-score/llms.txt)
[Text Case Format Converter](https://capytoolkit.com/tools/text/case-converter/): camelCase, snake_case, SCREAMING_SNAKE, kebab-case, Title Case, and more. See more: [resources](https://capytoolkit.com/tools/text/case-converter/llms.txt)
[Offline & Private AI Text Detector](https://capytoolkit.com/tools/text/offline-private-ai-text-detector/): Score how AI-generated your writing reads, fully offline and private in your browser, with no signup and no paywall. See more: [resources](https://capytoolkit.com/tools/text/offline-private-ai-text-detector/llms.txt)
[Speaker Frequency Sweep & Resonance Tester](https://capytoolkit.com/tools/audio/speaker-sweep/): Sweep 20 Hz – 20 kHz to find resonances, rattle points, and drop-off frequencies — 100% local. See more: [resources](https://capytoolkit.com/tools/audio/speaker-sweep/llms.txt)
[Decibel & SPL Cross-Domain Calculator](https://capytoolkit.com/tools/audio/decibel-calc/): Convert between dB, watts, volts, and sound pressure level, with the underlying formula shown. See more: [resources](https://capytoolkit.com/tools/audio/decibel-calc/llms.txt)
[Microphone Quality, Noise & Latency Tester](https://capytoolkit.com/tools/audio/mic-test/): Noise floor, clipping, frequency response, echo loopback, and round-trip latency — 100% local. See more: [resources](https://capytoolkit.com/tools/audio/mic-test/llms.txt)
[Resistor Color Code Calculator](https://capytoolkit.com/tools/math/resistor-calc/): 4-band, 5-band, and 6-band resistor decoding with tolerance, temperature coefficient, and E-series lookup. See more: [resources](https://capytoolkit.com/tools/math/resistor-calc/llms.txt)
[Ohm's Law & Power Calculator](https://capytoolkit.com/tools/math/ohms-law/): Enter any two of voltage, current, resistance, or power, and solve for the rest instantly. See more: [resources](https://capytoolkit.com/tools/math/ohms-law/llms.txt)
[Engineering Unit Converter](https://capytoolkit.com/tools/math/engineering-unit-converter/): SI, imperial, and domain-specific units spanning length, mass, temperature, pressure, energy, and more. See more: [resources](https://capytoolkit.com/tools/math/engineering-unit-converter/llms.txt)
[Electrical Unit Converter](https://capytoolkit.com/tools/math/electricity-unit-converter/): Charge, current, voltage, resistance, capacitance, inductance, and more, converted with SI precision. See more: [resources](https://capytoolkit.com/tools/math/electricity-unit-converter/llms.txt)
[Aspect Ratio & Letterbox Calculator](https://capytoolkit.com/tools/math/aspect-ratio/): Resolve display resolutions and scaling for any ratio, with letterbox bar dimensions calculated automatically. See more: [resources](https://capytoolkit.com/tools/math/aspect-ratio/llms.txt)
[Password Entropy Analyser](https://capytoolkit.com/tools/security/password-entropy/): Shannon entropy, zxcvbn pattern analysis, and GPU crack-time estimates — 100% offline, nothing uploaded. See more: [resources](https://capytoolkit.com/tools/security/password-entropy/llms.txt)
[PII Scrubber](https://capytoolkit.com/tools/security/pii-scrubber/): Detect and tokenize PII, secrets, and internal data before sending prompts to AI — 100% local, nothing uploaded. See more: [resources](https://capytoolkit.com/tools/security/pii-scrubber/llms.txt)
[File Hash Verifier](https://capytoolkit.com/tools/security/hash-verifier/): Compute SHA-256, SHA-512, SHA-1, and MD5 checksums for any file — compare against a published checksum. See more: [resources](https://capytoolkit.com/tools/security/hash-verifier/llms.txt)
[EXIF & Image Metadata Scrubber](https://capytoolkit.com/tools/security/exif-scrubber/): Strip GPS, timestamps, and device data from images — 100% local, nothing uploaded. See more: [resources](https://capytoolkit.com/tools/security/exif-scrubber/llms.txt)
[URL Encoder / Decoder](https://capytoolkit.com/tools/security/url-encoder/): Percent-encode and decode URLs and query strings with component parsing. See more: [resources](https://capytoolkit.com/tools/security/url-encoder/llms.txt)
[Browser Fingerprint & Privacy Leak Inspector](https://capytoolkit.com/tools/security/browser-fingerprint/): See exactly what your browser leaks — canvas hash, WebGL renderer, audio fingerprint, fonts, and 30+ signals. 100% local. See more: [resources](https://capytoolkit.com/tools/security/browser-fingerprint/llms.txt)
[Offline OCR & Document Redactor](https://capytoolkit.com/tools/security/ocr-redactor/): Extract text and redact sensitive regions from documents — Tesseract WASM, 100% local, nothing uploaded. See more: [resources](https://capytoolkit.com/tools/security/ocr-redactor/llms.txt)
[Cloud Config Sanitizer](https://capytoolkit.com/tools/security/config-sanitizer/): Validate Kubernetes, Terraform, and YAML manifests locally — detect secrets, security smells, and generate a sanitized safe version. See more: [resources](https://capytoolkit.com/tools/security/config-sanitizer/llms.txt)
[X.509 Certificate Inspector](https://capytoolkit.com/tools/security/cert-inspector/): Paste any PEM or DER certificate and inspect validity, SANs, key algorithm, chain depth, and expiry — client-side only. See more: [resources](https://capytoolkit.com/tools/security/cert-inspector/llms.txt)
[WCAG Contrast Checker](https://capytoolkit.com/tools/design/contrast-checker/): AA and AAA contrast ratio testing with hex, RGB, and HSL input. See more: [resources](https://capytoolkit.com/tools/design/contrast-checker/llms.txt)
[Color Format Converter](https://capytoolkit.com/tools/design/color-converter/): Convert between HEX, RGB, HSL, HSV, OKLCH, and CSS named colours. See more: [resources](https://capytoolkit.com/tools/design/color-converter/llms.txt)
[CSS Gradient Builder](https://capytoolkit.com/tools/design/gradient-builder/): Visual linear and radial gradient editor with live CSS output. See more: [resources](https://capytoolkit.com/tools/design/gradient-builder/llms.txt)
[IPv4 / IPv6 Subnet & CIDR Calculator](https://capytoolkit.com/tools/network/subnet-calculator/): Calculate network ranges, broadcast addresses, and host counts for IPv4 and IPv6 — all processed locally. See more: [resources](https://capytoolkit.com/tools/network/subnet-calculator/llms.txt)
[HTTP Status Code Reference](https://capytoolkit.com/tools/network/http-status/): Searchable reference for all HTTP 1xx–5xx codes with usage notes. See more: [resources](https://capytoolkit.com/tools/network/http-status/llms.txt)
[URL Parser & Inspector](https://capytoolkit.com/tools/network/url-parser/): Decompose any URL into protocol, host, path, params, and fragment. See more: [resources](https://capytoolkit.com/tools/network/url-parser/llms.txt)
[MIME Type Reference](https://capytoolkit.com/tools/network/mime-reference/): Searchable MIME database with extension mapping and RFC sources. See more: [resources](https://capytoolkit.com/tools/network/mime-reference/llms.txt)
[P2P Network Tester](https://capytoolkit.com/tools/network/p2p-tester/): Test WebRTC peer-to-peer latency, jitter, and packet loss between two browsers — STUN probe, live sparkline, zero cloud. See more: [resources](https://capytoolkit.com/tools/network/p2p-tester/llms.txt)
[IndexNow URL Submitter](https://capytoolkit.com/tools/network/indexnow-submitter/): Submit URLs to Bing, Yandex, Naver, and more via IndexNow — paste direct URLs or sitemap URLs, batched and proxied. See more: [resources](https://capytoolkit.com/tools/network/indexnow-submitter/llms.txt)
[Passport & Visa Photo Cropper](https://capytoolkit.com/tools/personal/passport-photo/): Crop a passport or visa photo to official millimetre size and eye-line on this device. Nothing uploaded.
[Image Shrink-to-Limit](https://capytoolkit.com/tools/personal/image-shrink-to-limit/): Reduce one image to an email, form, or app file-size cap on this device. Nothing uploaded.
[Local PDF Toolkit](https://capytoolkit.com/tools/personal/pdf-toolkit/): Merge, split, reorder, rotate, and compress PDFs on this device. Nothing uploaded.

## Blog

### Blog Index & Categories

[Blog](https://capytoolkit.com/blog/): Articles, buying guides, and how-to content covering monitors, audio, developer tools, and security.

[Guides & How-Tos](https://capytoolkit.com/blog/guides/): Master hardware testing, software troubleshooting, and developer workflows. Read step-by-step tech guides that maximize browser-based utility tools. See more: [posts](https://capytoolkit.com/blog/guides/llms.txt)
[Buying Guides](https://capytoolkit.com/blog/buying-guides/): Read expertly researched buying guides for monitors, headphones, and keyboards. Discover tested hardware recommendations to upgrade your desk setup today. See more: [posts](https://capytoolkit.com/blog/buying-guides/llms.txt)
[Audio & Acoustics](https://capytoolkit.com/blog/audio/): Explore audio hardware guides, headphone comparisons, and room acoustics fundamentals. Optimize your home or studio audio setup with expert technical tips. See more: [posts](https://capytoolkit.com/blog/audio/llms.txt)
[Developer Tools](https://capytoolkit.com/blog/developer-tools/): Improve programming productivity with developer guides and local workflow tips. Learn how to work smarter and faster using privacy-first browser utilities. See more: [posts](https://capytoolkit.com/blog/developer-tools/llms.txt)
[Security & Privacy](https://capytoolkit.com/blog/security-privacy/): Implement practical data security workflows. Read guides covering encryption, privacy-first tools, and metadata protection strategies to stay safe online. See more: [posts](https://capytoolkit.com/blog/security-privacy/llms.txt)
[Hardware & Peripherals](https://capytoolkit.com/blog/hardware/): Learn to test mice, keyboards, and gaming controllers accurately. Read hardware guides on measuring input lag and polling rates directly in your browser. See more: [posts](https://capytoolkit.com/blog/hardware/llms.txt)

### Recent Posts

[After IndexNow: 6 Launch Channels Indie Founders Skip, and How to Hit Them in a Weekend](https://capytoolkit.com/blog/guides/after-indexnow-6-launch-channels-indie-founders-skip-weekend/): IndexNow pings every URL, then launch week goes silent. Here are six distribution channels solo founders skip, with weekend time budgets for each.
[Debugging API Responses Locally in the Browser: A JSON Formatter Workflow That Never Sends Your Payload](https://capytoolkit.com/blog/developer-tools/debugging-api-responses-locally-browser-json-formatter-workflow/): A three-minute local debugging routine for API responses: format, validate, locate the broken line, browse large payloads as a tree, and minify.
[Running an LLM in Your Browser: Verifying WebGPU, Model Hashes, and Local Inference Without a Server](https://capytoolkit.com/blog/developer-tools/running-llm-browser-verifying-webgpu-model-hashes-local-inference/): Verify a local browser LLM before you trust it: check WebGPU support, hash the model file, and audit what your browser leaks while it runs.
[Post-Quantum TLS in 2026: What a Certificate Inspector Can and Cannot Tell You Yet](https://capytoolkit.com/blog/security-privacy/post-quantum-tls-certificate-inspector-can-and-cannot-tell-you/): Half the web negotiates post-quantum handshakes while certificates stay classical. Run a five-minute local audit to see where your domains stand.
[Where Your Text Goes When You Check It for AI: Six Detectors Compared](https://capytoolkit.com/blog/security-privacy/where-your-text-goes-when-you-check-it-for-ai-six-detectors-compared/): Six AI detectors compared on signup, free caps, price, and where your text is actually processed, plus how to read a 99% accuracy claim.
[Testing a USB Audio Interface or DAC at Home: Browser Checks for Noise Floor, Loopback, and Latency](https://capytoolkit.com/blog/audio/testing-usb-audio-interface-dac-browser-noise-floor-loopback-latency/): Test a USB audio interface or DAC noise floor, loopback quality, clipping headroom, and round-trip latency in your browser before the return window closes.
[Verifying Your FIDO2 Hardware Security Key: What a Browser Can Confirm](https://capytoolkit.com/blog/security-privacy/verifying-your-fido2-hardware-security-key-what-a-browser-can-confirm/): Verify your FIDO2 key is genuine with a browser-only routine: read its attestation chain, check fingerprint leaks, and test backup password strength.
[Privacy-First Smart Home Cameras and Doorbells: Local Processing vs. Cloud, and What To Check](https://capytoolkit.com/blog/buying-guides/privacy-smart-home-cameras-doorbells-local-cloud-check/): How to read past camera marketing and buy a smart home camera or doorbell that keeps footage local, from on-device AI to open protocols.
[How to Tell If a microSD Card or External SSD Is Fake or Slower Than Advertised](https://capytoolkit.com/blog/buying-guides/tell-if-microsd-card-external-ssd-fake-slower-advertised/): How to catch counterfeit and underperforming storage before you lose data, using browser-based hash verification alongside native capacity and speed tools.
[Hall-Effect Controllers Still Drift: How to Verify the "Drift-Free" Claim in Your Browser](https://capytoolkit.com/blog/buying-guides/hall-effect-controllers-still-drift-verify-drift-free-claim-browser/): Paid extra for Hall-effect sticks? Read raw Gamepad API axis values in your browser to confirm whether your controller actually drifts.
[Wide-Gamut Display Color Management for Web Designers: Converting Display P3 and Adobe RGB to sRGB in the Browser](https://capytoolkit.com/blog/guides/wide-gamut-display-color-management-web-designers/): How wide-gamut displays create colors sRGB cannot represent, how browsers handle the mismatch, and how to verify colors stay in gamut before production.
[UUID v4 or v7 as a Primary Key: What Changes in Your Index, Your Logs, and Your URLs](https://capytoolkit.com/blog/developer-tools/uuid-v4-v7-as-primary-key-what-changes-your-index-your-logs-your-urls/): The UUID version digit decides how your index absorbs writes, what a public identifier reveals, and how keys behave in logs and exports.
[Testing a New Soundbar with Browser Tools: Frequency Response, SPL, and Lip-Sync Checks You Can Run at Home](https://capytoolkit.com/blog/audio/testing-soundbar-browser-tools-frequency-response-spl-lip-sync-checks/): Use three free browser tools to measure frequency response, SPL, and A/V sync on your soundbar. No lab gear, no uploads.
[Power Bank and GaN Charger Capacity Claims: How to Verify the mAh-to-Wh Math Yourself](https://capytoolkit.com/blog/buying-guides/power-bank-charger-capacity-claims-verify-mah-wh-math-yourself/): Battery listings show mAh, not watt-hours. Learn to convert, spot inflated claims, and pick a power bank that delivers.
[Portable Second Monitors: How to Verify a Panel Before Your Return Window Closes](https://capytoolkit.com/blog/buying-guides/portable-second-monitors-verify-panel-before-return-window/): A browser-only checklist for testing dead pixels, backlight bleed, uniformity, USB-C connectivity, and defect documentation on delivery day.
[What NPU TOPS Doesn't Tell You: How Memory Bandwidth Bounds Local LLM Performance](https://capytoolkit.com/blog/buying-guides/npu-tops-vs-memory-bandwidth-local-llm-ai-pc/): Decode spec sheets to find memory bandwidth, not TOPS. Learn to evaluate NPU hardware for local LLM performance before you buy.
[Portable Power Station Claims Don't Add Up: How to Check the Math Yourself](https://capytoolkit.com/blog/guides/portable-power-station-claims-dont-add-up-check-math-yourself/): Marketing specs obscure the real runtime. Use Ohm's Law and free browser math tools to verify power station capacity before you buy.
[Verifying LED Panel Driver Failures Before Desoldering: What Ohm's Law Covers That a Visual Inspection Misses](https://capytoolkit.com/blog/hardware/led-panel-driver-failures-verify-ohms-law-before-desoldering/): Measure power-rail voltage, decode resistor markings, and compute expected dissipation to decide if your LED driver is worth repairing before desoldering.
[What Mechanical Keyboard Specs Actually Matter and How to Verify Them in Your Browser](https://capytoolkit.com/blog/buying-guides/mechanical-keyboard-specs-actually-matter-how-to-verify-browser/): Which keyboard specs separate real improvements from marketing filler, and how to verify polling rate, debounce, and rollover claims before you buy.
[Wi-Fi 7 Router Buying Guide: What the Specs Actually Mean for Gaming and Streaming](https://capytoolkit.com/blog/buying-guides/wifi-7-router-buying-guide-specs-gaming-streaming/): Decode Wi-Fi 7 spec sheets and learn which router features affect gaming latency, streaming stability, and NAT behavior.