SunSpec Explorer

Connect to a SunSpec inverter, meter or battery, see every model it exposes fully decoded, read once or poll, record and export, without ever writing to the device.

Built by OT Fabric on go-sunspec and go-modbus. MIT licensed. Status: preview; the current release is on the releases page.

The demo above, in full quality: docs/media/demo.mp4 (one minute, against a device simulated with sunspecctl serve).

The same Explorer, with the same features and the same screens, comes in two forms. Pick by where the device is.

There is no "remote mode" in the desktop application: remote use is always the daemon and a browser. Both forms only read (Modbus function codes 3 and 4); the client refuses anything else before it reaches the wire. See SECURITY.md.

Browse decoded models. Label, value with units, scale factor, enum and bitfield names, access, mandatory and static flags, raw value and register address of every point; a description per point. Not-implemented points are labeled as such, never shown as 65535.	Repeating and nested groups appear as instances (module [1], module [2], Crv [1] / Pt [3]). Models without a known schema show their raw registers.
Poll at whole-second intervals, in the engine, never overlapping; stale values are marked. Record the samples as JSON Lines, with a warning when the storage is temporary.	Save a copy of a recording as JSON Lines or CSV when it stops. On the daemon a recording keeps running when you close the browser or the tunnel drops.
Export a snapshot (JSON, with a published schema), the points as CSV, or a device file that sunspecctl serve turns back into the same device.	A failed connect shows every probe and its error, and says that a wrong unit ID is the usual cause.

Also: targets over Modbus/TCP, RTU over TCP, Modbus/TCP Security (TLS) and serial RS-485; a light theme (screenshot) and full keyboard navigation; a collapsible model list; re-discovery when a device's model chain changes.

Every release has the files below, a checksum file (sunspec-explorer-<version>-checksums.txt) and build provenance. The files are not code-signed yet, so macOS and Windows warn on the first start; the steps for that are under each platform.

All downloads are on the releases page. The commands below fetch the latest release and check its checksum.

VERSION=$(curl -fsSL https://api.github.com/repos/otfabric/sunspec-explorer/releases/latest | sed -n 's/.*"tag_name": *"v\([^"]*\)".*/\1/p')
ARCH=$(uname -m | sed 's/x86_64/amd64/')            # arm64 or amd64
FILE="sunspec-explorer-${VERSION}-darwin-${ARCH}.zip"
BASE="https://github.com/otfabric/sunspec-explorer/releases/download/v${VERSION}"
curl -fsSLO "${BASE}/${FILE}" && curl -fsSLO "${BASE}/sunspec-explorer-${VERSION}-checksums.txt"
grep " ${FILE}\$" "sunspec-explorer-${VERSION}-checksums.txt" | shasum -a 256 -c -
ditto -x -k "${FILE}" /Applications
open "/Applications/SunSpec Explorer.app"

The app is not notarized. If macOS refuses to open it, go to System Settings → Privacy & Security and choose "Open Anyway" once, or remove the quarantine flag: xattr -dr com.apple.quarantine "/Applications/SunSpec Explorer.app" (a file downloaded with curl usually has none).

In PowerShell:

$version = (Invoke-RestMethod https://api.github.com/repos/otfabric/sunspec-explorer/releases/latest).tag_name.TrimStart('v')
$file    = "sunspec-explorer-$version-windows-amd64.zip"
$base    = "https://github.com/otfabric/sunspec-explorer/releases/download/v$version"
Invoke-WebRequest "$base/$file" -OutFile $file
Invoke-WebRequest "$base/sunspec-explorer-$version-checksums.txt" -OutFile checksums.txt
$expected = ((Select-String -Path checksums.txt -Pattern " $file$").Line -split '\s+')[0]
if ((Get-FileHash $file -Algorithm SHA256).Hash -ne $expected.ToUpper()) { throw "checksum mismatch" }
Expand-Archive $file -DestinationPath "$env:LOCALAPPDATA\Programs\SunSpec Explorer" -Force
& "$env:LOCALAPPDATA\Programs\SunSpec Explorer\sunspec-explorer-$version-windows-amd64\sunspec-explorer.exe"

SmartScreen shows "Windows protected your PC" the first time: choose "More info", then "Run anyway". Windows 10 needs the WebView2 runtime; Windows 11 has it. Serial devices are named COM3 and the like; the application lists them.

The desktop application needs GTK 4 and WebKitGTK 6.0: Debian 13, Ubuntu 24.04 or later. On Debian 11 or 12 use the daemon on the same machine and a browser (next section).

sudo apt install libgtk-4-1 libwebkitgtk-6.0-4
VERSION=$(curl -fsSL https://api.github.com/repos/otfabric/sunspec-explorer/releases/latest | sed -n 's/.*"tag_name": *"v\([^"]*\)".*/\1/p')
ARCH=$(dpkg --print-architecture)                    # amd64 or arm64
FILE="sunspec-explorer-${VERSION}-linux-${ARCH}.tar.gz"
BASE="https://github.com/otfabric/sunspec-explorer/releases/download/v${VERSION}"
curl -fsSLO "${BASE}/${FILE}" && curl -fsSLO "${BASE}/sunspec-explorer-${VERSION}-checksums.txt"
grep " ${FILE}\$" "sunspec-explorer-${VERSION}-checksums.txt" | sha256sum -c -
tar xzf "${FILE}" && sudo install -m 0755 "${FILE%.tar.gz}/sunspec-explorer" /usr/local/bin/
sunspec-explorer

For serial devices your user needs the dialout group (sudo usermod -aG dialout $USER, then log in again).

One static binary per architecture, no libraries, no display: the same file runs on Debian 11, 12 and 13.

VERSION=$(curl -fsSL https://api.github.com/repos/otfabric/sunspec-explorer/releases/latest | sed -n 's/.*"tag_name": *"v\([^"]*\)".*/\1/p')
ARCH=$(dpkg --print-architecture | sed 's/armhf/armv7/')   # amd64, arm64 or armv7
FILE="sunspec-explorerd-${VERSION}-linux-${ARCH}.tar.gz"
BASE="https://github.com/otfabric/sunspec-explorer/releases/download/v${VERSION}"
curl -fsSLO "${BASE}/${FILE}" && curl -fsSLO "${BASE}/sunspec-explorer-${VERSION}-checksums.txt"
grep " ${FILE}\$" "sunspec-explorer-${VERSION}-checksums.txt" | sha256sum -c -
tar xzf "${FILE}" && sudo install -m 0755 "${FILE%.tar.gz}/sunspec-explorerd" /usr/local/bin/
sunspec-explorerd version

Try it with sunspec-explorerd (it listens on 127.0.0.1:8765), or run it as a service with the systemd unit in the archive (sunspec-explorerd.service); both are described in docs/REMOTE-USE.md. The daemon connects only to private and link-local addresses by default (--allow-target adds others) and opens serial devices only when you name them (--allow-serial '/dev/ttyUSB*').

The quickest way to try the browser form, also on macOS and Windows:

docker run -d --name explorer -p 127.0.0.1:8765:8765 -v explorer-data:/data ghcr.io/otfabric/sunspec-explorerd:latest
docker exec explorer sunspec-explorerd url      # the address to open, access token included

Publish the port on 127.0.0.1 only, as shown. From the container, a device on your own machine is host.docker.internal. More in docs/REMOTE-USE.md.

Besides the checksum, each file has a build provenance attestation that proves the release workflow of this repository built it:

gh attestation verify sunspec-explorerd-<version>-linux-arm64.tar.gz --repo otfabric/sunspec-explorer
gh attestation verify oci://ghcr.io/otfabric/sunspec-explorerd:<version> --repo otfabric/sunspec-explorer

Nothing is installed on your workstation:

gateway$      sunspec-explorerd                              # listens on 127.0.0.1:8765
workstation$  ssh -N -L 8765:127.0.0.1:8765 user@gateway     # forward the port, keep it running
gateway$      sunspec-explorerd url                          # prints http://127.0.0.1:8765/#token=...

Open that URL in a browser on the workstation. The part after # is the access token: treat the URL like a password. When the tunnel drops, the daemon keeps polling and recording, and the page picks up where it left off. Details, systemd, TLS and serial devices, Debian notes: docs/REMOTE-USE.md.

sunspecctl can simulate a device:

sunspecctl template --model 1,103,160 -o device.json     # then fill in some values
sunspecctl serve --file device.json --url tcp://127.0.0.1:1502

In the desktop application, connect to tcp://127.0.0.1:1502, unit ID 1. For the daemon, allow the local address, which is off by default: sunspec-explorerd --allow-target 127.0.0.0/8. The demo and the screenshots above were made exactly this way.

Go 1.25 or later and Node.js 22 or later; for the desktop application also a C compiler and the platform's webview (Xcode command line tools, the WebView2 runtime, or GTK 4 and WebKitGTK 6.0).

make frontend-install   # once
make dev                # build the user interface and run the desktop application
make build              # ./bin/sunspec-explorer and ./bin/sunspec-explorerd
make bundle-macos       # ./bin/SunSpec Explorer.app
make build-daemon-all   # the daemon for linux amd64, arm64 and armv7
make docker             # the daemon's container image
make check              # all checks

• Remote use: the daemon, SSH, systemd, containers, serial and TLS devices
• JSON Schemas: snapshot, recording, API
• Requirements, Architecture, Branding, Proposal review
• Release notes, Security, Contributing; agents start with AGENTS.md

License: MIT.