Is my microphone audio recorded or uploaded?

No. Audio is processed in real time inside the page and never written to disk or sent anywhere. The tools that need the microphone request permission explicitly, and revoking it in your browser’s site settings stops access immediately.

How accurate is a browser tuner?

Accurate to within a couple of cents for a clean, sustained note, which is well inside what is audible and sufficient for tuning any instrument. Accuracy degrades with background noise, very low notes — long wavelengths need a longer analysis window — and heavily distorted signals where the fundamental is weak relative to the harmonics.

Why does the metronome stay in time when other browser timers drift?

Because beats are scheduled ahead on the Web Audio clock, which is driven by the audio hardware, rather than fired by setTimeout. JavaScript timers are throttled in background tabs and jitter under load; the audio clock does neither. The visual indicator may stutter, but the sound does not.

Does the image metadata viewer strip EXIF from my photo?

It reads and displays metadata but does not modify the file. It is worth checking before sharing photos publicly: phone cameras commonly embed exact GPS coordinates, the capture timestamp and a device identifier, and most messaging apps and social platforms — though not all, and not for every upload path — remove them for you.

Media & Audio Tools — Tuner, Metronome & Analysis

Audio tools built on the Web Audio API, plus a pair of image utilities — all running on your own device.

13 tools · Reviewed by Mimamsa, Founder & Engineer, CodeLint.Dev

Everything here uses the browser’s own audio stack. The Web Audio API provides a sample-accurate clock and real-time FFT analysis, which is what makes an in-browser tuner or metronome genuinely usable rather than a toy — timing is scheduled against the audio clock rather than JavaScript timers, so the beat does not wander.

The tools that listen — the tuner, the pitch detector, the spectrum analyser — need microphone permission, and the audio is processed entirely in the page. No recording is made, nothing is uploaded, and revoking the permission stops it immediately. Everything else, including the tone and noise generators, is pure synthesis with no input at all.

The two image tools sit here for the same reason: the colour picker and the metadata inspector both read a file locally. The metadata inspector is worth knowing about for privacy reasons alone — photographs from a phone routinely carry GPS coordinates, a device serial number and a precise timestamp in their EXIF block, all of which travel with the file when you share it.

Tuning & timing

Instrument Tuner Chromatic tuner with cent-accurate deviation, presets for guitar, bass, ukulele and violin, and adjustable A4 reference.Metronome Sample-accurate metronome scheduled on the audio clock, with time signatures, accented downbeats and subdivisions.Tap Tempo Tap along to find a track’s BPM, averaged over a rolling window so a single mistimed tap does not skew the reading.Pitch Detector Real-time fundamental frequency detection from the microphone, showing the nearest note and cent offset.

Signal generation & analysis

Tone Generator Sine, square, triangle and sawtooth at any frequency — for testing speakers, headphones and room response.Noise Generator White, pink and brown noise with a proper spectral shape, for masking, testing or concentration.Spectrum Analyser Live FFT spectrum from the microphone, for identifying hum, resonance and room modes.Audio File Inspector Reads duration, sample rate, channel count, bit depth and container details from a local audio file.

Music theory

Chord & Scale Explorer Chord spellings and scale degrees in any key, with the notes and intervals shown for each.Note Frequency Table Equal-temperament frequencies for every note across the full MIDI range, with adjustable A4 tuning.Transposition Calculator Transpose between concert pitch and transposing instruments — B♭ trumpet, E♭ alto sax, F horn and the rest.

Image utilities

Colour Picker Pick colours from an uploaded image and read them back as HEX, RGB, HSL or OKLCH, with palette extraction.Image Metadata Viewer Read EXIF, IPTC and XMP data — camera, lens, exposure, timestamp and any embedded GPS coordinates.

Frequently asked questions

Is my microphone audio recorded or uploaded?: No. Audio is processed in real time inside the page and never written to disk or sent anywhere. The tools that need the microphone request permission explicitly, and revoking it in your browser’s site settings stops access immediately.
How accurate is a browser tuner?: Accurate to within a couple of cents for a clean, sustained note, which is well inside what is audible and sufficient for tuning any instrument. Accuracy degrades with background noise, very low notes — long wavelengths need a longer analysis window — and heavily distorted signals where the fundamental is weak relative to the harmonics.
Why does the metronome stay in time when other browser timers drift?: Because beats are scheduled ahead on the Web Audio clock, which is driven by the audio hardware, rather than fired by setTimeout. JavaScript timers are throttled in background tabs and jitter under load; the audio clock does neither. The visual indicator may stutter, but the sound does not.
Does the image metadata viewer strip EXIF from my photo?: It reads and displays metadata but does not modify the file. It is worth checking before sharing photos publicly: phone cameras commonly embed exact GPS coordinates, the capture timestamp and a device identifier, and most messaging apps and social platforms — though not all, and not for every upload path — remove them for you.

Other tool categories

Barcode & QR Static QR codes and barcodes generated in your browser — no redirect service, no expiry, no account.Generators & Utilities Generators and converters for the values you need constantly and should never have to fetch from a server.Reference & Data The lookup tables you open a dozen times a week, each searchable and on one page.Date & Time Timers and date arithmetic that stay accurate when the tab is in the background.