APRStac runs as a single binary with no dependencies. Download the correct version for your platform from the downloads page, then run it from a terminal.
On first run, APRStac creates a default configuration file (aprstac.toml) and a SQLite database (aprstac.db) in the working directory. Your browser will open automatically to the web interface at http://localhost:14501.
Navigate to Settings → Station to configure your callsign, SSID, symbol, and position. If you have a GPS module connected, you can enable auto-position updates under Settings → GPS.
APRTAC to identify itself in the APRS network.By default, APRStac only listens on 127.0.0.1 (your local machine). To access it from other devices on your LAN, such as your phone or another computer, go to Settings → General and enable Enable Local Network Access. This binds the server to 0.0.0.0, making it available on all network interfaces.
After enabling, restart APRStac. Then access the web interface from any device on your network using your computer's IP address, for example http://192.168.1.100:14501.
Ports are your connections to the APRS network. All ports are configured from Settings → Ports.
Connect a local TNC via serial port. Select the serial device (e.g., /dev/ttyUSB0 on Linux, COM3 on Windows), set the baud rate (typically 9600 or 1200), and enable the port.
Connect to a remote KISS TNC over the network. Enter the host and port. Auto-reconnect with exponential backoff (5s to 60s) is built in.
Connect to the APRS Internet System. Enter a regional server (e.g., rotate.aprs2.net), port 14580, your callsign, and APRS-IS passcode. Optionally add a server-side filter string to limit traffic (e.g., r/35.0/-80.0/100 for a 100 km radius).
Share packets on your local network via UDP broadcast on port 14581. Useful for linking multiple APRStac instances on a LAN.
Bridge a Meshtastic LoRa device over your network. Enter the device's IP address and port (default 4403). See Meshtastic Integration for details.
Bridge a Meshtastic LoRa device connected via USB. Select the serial port (auto-detected at 115200 baud). See Meshtastic Integration for details.
Connect to a VARA FM software modem for connected-mode packet sessions over VHF/UHF. Enter the host and command/data ports of your running VARA FM instance. Note: VARA FM ports can only be used for BBS and Fileshare at this time.
The email gateway forwards APRS messages to your email inbox and lets you reply from email back to APRS stations.
Note: Gmail, Hotmail, and Yahoo are not supported due to their restrictions on third-party IMAP/SMTP access. You can use your own dedicated mail server, or request an APRStac email account to use with the gateway.
Navigate to Settings → Email and configure:
EMAIL-9)Any APRS station can send an email through your gateway by addressing a message to your listen callsign. The message body should be formatted as:
recipient@example.com Your message text hereThe first word (the email address) is used as the destination. Everything after it becomes the email body. For example, sending this APRS message to EMAIL-9:
john@gmail.com Hello from the field!will deliver an email to john@gmail.com with the body "Hello from the field!" and the sender's callsign in the subject line.
To send an APRS message from your email, compose a new email (or reply to a forwarded one) to your gateway's email address. Set the subject line to the destination callsign (e.g., KN4MKB-7), and write your message in the email body. APRStac polls your IMAP inbox and transmits the body as an APRS message addressed to the callsign in the subject. The reply is sent from your listen callsign.
Keep your message under 67 characters, which is the maximum length for an APRS message. Anything beyond that will be truncated.
APRStac can bridge Meshtastic LoRa mesh networks to APRS, displaying mesh nodes on the map alongside other RF ports and internet stations.
Add a Meshtastic port under Settings → Ports:
4403)115200 baud)Enable Import Nodes to pull position data from all nodes in the mesh handshake and ongoing position broadcasts.
Meshtastic packets are tagged as local-only and are never forwarded to RF or APRS-IS. They appear on the map with a [Mesh] badge but do not enter the APRS network. This is intentional, Meshtastic nodes are display-only.
Meshtastic nodes are assigned APRS-compatible callsigns automatically. Priority order: licensed callsign from the node's long_name, then long_name with hex suffix, then short_name with hex suffix, then the full hex node ID.
APRStac can post APRS packets to a Discord channel as formatted embeds using a webhook. This is useful for monitoring station activity from Discord.
Each packet is posted as a color-coded Discord embed with the station callsign, decoded data, and raw packet. Packets with position data include a clickable link to aprs.fi.
APRStac includes a built-in tile cache and MBTiles reader for offline map operation, ideal for field deployments or Raspberry Pi setups without reliable internet.
By default, APRStac fetches map tiles from OpenStreetMap and caches them in a separate SQLite database (tiles.db). Cached tiles are served instantly on subsequent views. The cache uses LRU eviction with a configurable maximum size (default 10 GB).
Supported tile layers: street (OpenStreetMap), topo (OpenTopoMap), satellite (ArcGIS), and dark (CartoDB).
For fully offline operation, place pre-downloaded .mbtiles files in the mbtiles/ directory (created automatically next to the database). Then select the file under Settings → Map.
You can download free raster MBTiles files from these sources:
Three modes are available:
View cache statistics and clear the cache from Settings → Map. The API also exposes tile cache endpoints for programmatic access.
APRStac includes a built-in BBS message board that you can host over RF, as well as a terminal client for connecting to other BBS systems.
Navigate to BBS → Host to configure your BBS:
KN4MKB-4). This must be different from your station callsign, digipeater callsign, and fileshare callsign. Click Save.Once enabled, remote stations can connect to your BBS listen callsign via AX.25 connected mode. They will see a welcome banner with available commands:
(L)IST [N], list the N most recent posting subjects(R)EAD #, read a posting by its number(P)OST <subject>, compose a new message (end with RRR on a new line)(E)XIT, disconnect from the BBSYou can also create and manage postings directly from the BBS → Postings tab in the web interface without needing an RF connection.
Navigate to BBS → Connect and fill in:
W4BBS-1)WIDE1-1)Click Connect to initiate the AX.25 SABM handshake. Once connected, you'll see a terminal interface where you can type commands and interact with the remote BBS. Send any text to receive the welcome menu.
The terminal displays received data in gray and your sent commands in the accent color. System messages (connection status, disconnects) appear in yellow. Click Disconnect to cleanly end the session, or Exit Session after disconnecting to return to the connect form.
APRStac implements AX.25 v2.0 modulo-8 connected mode with a window size of 4 I-frames. Retransmission (T1) and keepalive (T3) timers run automatically. The connection supports full bidirectional data exchange over RF.
APRStac includes a file hosting and transfer system that operates over AX.25 connected mode, allowing stations to share files over RF.
Navigate to Fileshare → Host to configure your fileshare:
KN4MKB-5). This must be different from your station callsign, digipeater callsign, and BBS callsign. Click Save.Navigate to Fileshare → Files to manage your hosted files. Drag and drop a file onto the upload area, or click to browse. Each file can be up to 10 MB. Click the delete button next to any file to remove it.
When a file is uploaded, APRStac automatically compresses it using the best of three algorithms (zstd, gzip, and brotli). Whichever produces the smallest result is stored. If none of them beat the original size, the file is kept uncompressed. This is fully automatic and requires no configuration.
Navigate to Fileshare → Connect, select a port, enter the remote station's fileshare callsign, and connect. The remote station's file list will load automatically. Click any file to begin the download. A progress indicator will show the transfer status.
Files are transferred as base64-encoded chunks over AX.25 I-frames with MD5 checksum verification on completion. Compressed files are automatically decompressed on arrival, so the downloaded file is always the original uncompressed version.
When a file transfer completes, the file is automatically saved to APRStac's internal storage. Completed downloads appear in the Downloaded Files section at the bottom of the Fileshare → Files tab. Each entry shows the filename, size, and the callsign of the station it was received from.
Click the Save button next to any downloaded file to save it to your computer. Files remain in the list until you delete them, so there is no need to worry about missing a download. You can return to the Files tab at any time to retrieve them.