EDF & BDF Viewer
Open and inspect biosignal recordings on Mac and iPad.
A high-performance, native SwiftUI viewer for European Data Format (EDF, EDF+) and BioSemi Data Format (BDF) files across EEG, ECG, sleep, and electrophysiology research. Zero runtime dependencies, no Java/Python environment, 100% on-device.
🔬 Pure Swift Parser · Min/Max Downsampling · Zero Network · 100% On-Device
Inspect Biosignal Recordings in Three Steps
No command line tools, no Python runtime setup, no cloud uploads. Open a file directly and begin inspecting data.
Open Instantly
Double-click in Finder, open from Files app, or drag and drop. A built-in synthetic demo recording is included.
Supports .edf, .edf+ (16-bit) and .bdf (24-bit) files.
Every Channel in Sync
Stacked montage with channel sidebar. Min/max envelope rendering ensures zero spike loss at any zoom level.
Trackpad swipe, pinch to zoom, or ⌘+ / ⌘- and arrow keys.
Measure & Inspect
Click or tap anywhere to place a crosshair cursor for exact time and amplitude readout. Inspect full file header metadata.
Calibrated physical units (μV, mV, bpm) and digital ranges.Engineered for Electrophysiology Research
From multi-gigabyte PSG sleep recordings to high-channel EEG, explore your signals with native desktop speed.
Peak-Preserving Min/Max Rendering
Naive downsampling drops transient spikes and high-frequency artifacts. Our dual-envelope algorithm calculates local extrema per pixel bucket, rendering millions of samples smoothly while preserving critical diagnostic peaks.
Accurate waveform display across 1-second to multi-hour time windows.
Interactive Measurement Crosshair
Place a measurement cursor at any point along the waveform timeline. Read calibrated physical values in exact units (μV, mV, bpm, %SpO2) alongside timestamps with microsecond precision.
Compare quiet vs active stretches with fixed or auto-fit amplitude scales.
Complete Header & Signal Calibration
Inspect recording start date and time, patient and recording identification fields, total data records, and per-signal calibration specifications (sample rate, physical/digital minimums & maximums, transducer type, and prefiltering).
Exact calibration decoding for standard 16-bit EDF and 24-bit BioSemi BDF formats.Core Capabilities
Native Swift & SwiftUI
Built purely in Swift with zero C runtime bridge or Python dependencies. Instant launch, responsive UI, and native macOS & iPadOS integration.
macOS 13+ and iPadOS 16+ Universal Purchase.All-Channels Montage
View all recording channels stacked in one synchronized view, or navigate through individual channels with sample rate and physical units displayed.
Side-by-side signal inspection with adjustable gain.Min/Max Decimation
Min/max envelope rendering ensures high-frequency spikes and artifacts remain visible at any zoom level without signal aliasing.
Peak-preserving rendering for massive recordings.Precision Cursor
Single-tap or click crosshair cursor reads exact timestamp and calibrated physical amplitude (μV, mV, bpm) across active channels.
Accurate point-by-point quantitative inspection.Header Inspector
Full inspection of recording metadata: format version, start date/time, record count, and per-signal digital and physical boundary definitions.
Complete file layout transparency for researchers.100% On-Device & Private
Zero analytics, zero tracking, no accounts, and no network requests. Your biosignal data never leaves your device.
Safe for sensitive research and local data analysis.Not a medical device
This is a file-viewing utility for research, educational, and engineering use. It does not diagnose, monitor, or support any clinical decision, and it is not intended for diagnosis or treatment.
Free for Research & Engineering
Everything required to open, inspect, zoom, navigate, and measure recordings is completely free. No subscriptions, no ads, no telemetry, and no account required.
Frequently Asked Questions
Which files can it open?
.edf and .bdf, including EDF+. 16-bit EDF and 24-bit BDF are both decoded using the calibration declared in the file header.
Is there a sample file?
Yes — a demo recording is built into the app, so there is something to look at before you have a file of your own. Its signals are generated, not recorded from a person.
Does it upload anything?
No. The app has no network features at all. See Privacy.
Why is my recording hard to read at the default window?
A ten-second window of a fast rhythm packs a great many cycles into the pane. Pinch in, or press ⌘+, to shorten the window; switch the gain away from Auto to hold the amplitude scale still while you move around.
Privacy
The developer collects nothing. The app has no analytics, no crash reporting, no accounts, no advertising, and no third-party SDKs. It makes no network requests of any kind.
- Recordings you open are read on your device and never leave it. The developer cannot see them.
- The only thing kept between launches is your list of recently opened files, stored on device so those files can be reopened without asking you to find them again.
- Exported files are written only where you choose to save them.
- Purchases are handled entirely by Apple. The developer never receives your payment details.
Because no personal data is collected, there is nothing to request, correct, or delete from the developer. Removing the app removes its stored list of recent files.
Support
✉️ Contact
Email us for any questions, bug reports, or format feedback. Including the app version and what you were opening will get you a faster answer.EDF & BDF Viewer is published by GoldenARC Digital. Not a medical device. For research, educational, and engineering use only.