github.com/chrissnell/graywolf @v0.14.10

Graywolf is a modern APRS station with a software modem, digipeater, iGate, and web UI. It bundles everything you need to put an APRS station on the air — from raw audio demodulation to APRS-IS gating — and makes it easy with a browser-based configuration interface.

Download the Latest Release — prebuilt for Linux (Debian/Ubuntu and Fedora/RHEL), macOS, and Windows.

Read the Handbook — installation, configuration, operation guide, and REST API reference.

Known-Working Configurations — community-tested hardware setups with exact settings. Check here for your device, and submit a PR if yours isn't listed.

Graywolf APRS Discord — community chat for help, discussion, and development.

Graywolf is used all around the world! See a map of currently active stations

Written by Chris Snell, NW5W.

The modem is written in Rust and includes a port of the AFSK demodulator from Dire Wolf by WB2OSZ. The decision-feedback AGC and hard-limiter correlator techniques are credited to Ion Todirel (W7ION), from his libmodem.

The AX.25 decoding, APRS operatations (beacons, digipeater, and iGate), and the web API is handled by a service written in the Go programming language.

The web frontend was built in Svelte.

Performance

Graywolf's AFSK demodulator beats Direwolf's best mode (-P AD+) on every track of the WA8LMF TNC test CD, at about 5% of a Raspberry Pi 5.

Reproduce with ./bench.sh.

Features

• Modern Web UI - GW is managed via the browser, with a responsive interface that works well on desktops and smartphones.

• Software Modem - High performance DSP written in Rust that's slightly more effective than Direwolf and much better than most hardware TNCs. Efficeint: uses about 19% of a single CPU core on a Raspberry Pi 5.

• Live Map - Like having a private aprs.fi for your station. Real-time APRS map with trails, digipeater paths, weather overlays, and beautiful animated NEXRAD weather radar, all rendered on our private vector basemap. You can download maps for your state/province/country for offline use!

• Messages - SMS-style APRS messaging with delivery status and unread badges

• Direct messages with auto-ACK and retry

• Tactical callsigns (e.g. GRAYWOLF, AMIGOS) for group nets
• RF-first delivery with APRS-IS fallback

• Long messages up to 200 characters

• Actions - Trigger scripts remotely with specially-crafted APRS messages

• Can trigger via shell script, Powershell script, or webhook

• Can be secured with one-time passwords a la Google Authenticator or 1Password

• AX.25 Terminal - Built-in connected-mode terminal client in the web UI

• Connect to BBSes, nodes, and other stations over AX.25

• Macros and configurable presets for quick connects

• Live channel monitor

• Push-to-Talk - Multiple PTT methods for any setup

• Serial RTS/DTR (Digirig, USB-serial adapters)

• CM108 USB HID GPIO (AIOC, homebrew sound card adapters)
• Linux GPIO (Raspberry Pi, BeagleBone)
• Hamlib rigctld (CAT control)
• VOX (voice-operated keying, no PTT wiring required)

• Digirig Lite Tone PTT (keys on a right-channel tone, no PTT wiring required)

• Digipeater - Full-featured APRS digipeater

• WIDEn-N path handling

• Preset-driven configuration (fill-in, wide-area, etc.)
• Duplicate suppression

• Per-path filtering

• iGate - Bidirectional APRS-IS gateway

• RF → APRS-IS and APRS-IS → RF gating

• Configurable filters

• Packet origin tracking in logs

• TNC Interfaces - Speak the protocols other packet software expects

• KISS TNC with native serial and network (TCP) support

• AGWPE TCP interface

• Beacons and GPS - Position reporting made easy

• Static and GPS-driven position beacons

• Status and telemetry beacons

• Configurable beacon intervals and paths

• Observability

• Prometheus metrics

• Packet logging to SQLite database, with search ability

• Live packet stream in the web UI

• Simple installation - single binary, SQLite config database

• systemd service unit

• Debian/Ubuntu (APT), Red Hat (RPM), and Arch (AUR) packages
• Windows installer
• macOS binaries
• Runs on x86-64 and ARM (Raspberry Pi)

Which download do I use?

Grab the build that matches your hardware from the latest release. On Linux, pick the .deb (Debian/Ubuntu), .rpm (Fedora/RHEL), or .tar.gz (anything else) with the matching architecture suffix.

Not sure? On Linux, run uname -m — its output is exactly the suffix to look for: x86_64, aarch64 (use the arm64 build), armv7l, or armv6l.

armv6l vs. armv7l: both are 32-bit ARM hard-float. The armv7l build enables NEON, so the Rust modem's demodulator runs vectorized and noticeably faster — use it whenever your board is Cortex-A7 or newer. The armv6l build is the universal fallback that runs on every 32-bit Pi (including the ARMv6-only Pi 1 / Zero) but stays scalar; it will also run on ARMv7 boards, just slower. Don't use armv7l on an ARMv6-only Pi — it will fail with an illegal-instruction error.

Running a 64-bit OS on a Pi 3/4/5? Prefer the arm64 build over either 32-bit one.