mapcan 0.22.0

A free, open-source CAN database editor.
Draw signals on the bit layout, keep the map in git, and get DBC, PDF, Excel and C code from one file.

CAN 2.0A/B · CAN FD · SAE J1939 · CANopen · Windows, Linux, VS Code

Try it on your DBC · Why not just DBC · Installation · Outputs · Documentation

Your CAN interface is described three times: in a spreadsheet or a Word document for the team, in a DBC for the bus analyzer and in the firmware's headers. Sooner or later they disagree, and nobody knows which one is right. mapcan keeps the interface in one YAML file and generates the rest from it, so they cannot drift apart. The file is reviewed in pull requests like code, and every mistake (overlapping signals, clashing IDs, unknown receivers) is reported with its line before anything is built.

Already have a DBC?

pipx install "mapcan[desktop]"              # or the Windows installer below
mapcan import dbc vehicle.dbc               # → vehicle.yaml
mapcan validate vehicle.yaml                # what your DBC got wrong, with lines
mapcan build vehicle.yaml -o build/         # PDF, Excel, HTML, DBC, C and Python at once
mapcan app vehicle.yaml                     # edit it on the bit layout

You keep your tools: the DBC exported back works in CANalyzer, SavvyCAN, PCAN-View and Wireshark.

Why not just a DBC file?

Who it is for

• Firmware engineers: generated C with IDs, enums, structs and pack/unpack, no dynamic memory.
• Test and validation: a Python module with the same frames for test benches, and a DBC for the analyzer.
• Systems engineers and leads: one reviewed source of truth, and a PDF or Excel specification for suppliers and customers, also in Russian and to ESKD/GOST.

Installation

Quick start

mapcan app                                  # the editor in its own window

Click New map… and pick a template (CANopen, J1939, CAN with explicit IDs or empty), or open one of the examples. Add devices, frames and signals in the tree and draw signals on the frame's bit layout; mistakes show up as you type. On the command line:

mapcan validate my-map.yaml                 # errors with file, line and column
mapcan build my-map.yaml -o build/          # every output at once

Outputs

Documents are produced in English or Russian, with your logo and templates; docs/cli.md has every command, the generated C code and the customization.

Editors

The mapcan app (mapcan app, or mapcan serve in a browser) edits a map in forms that adapt to the protocol and on the bit layout: drag across free bits to add a signal, drag a signal to move it. It checks the map as you type, previews every output and compares versions from git. Files keep their comments and formatting, so a diff shows only what you changed. More in docs/web.md.

VS Code with the mapcan extension checks maps as you type and adds the Map view, the Node panel with the bit layout, hovers, quick fixes, rename, export and the map's history (vscode/README.md). Any editor with a YAML language server completes keys from the JSON Schema.

A map

mapcan: 1

document:
  title: Electric vehicle example map
  version: 0.1.0
  language: en

buses:
  - name: powertrain
    bitrate: 500000
    protocol: can
    devices:
      - name: bms
        frames:
          - name: bms_status
            id: 0x100
            length: 8
            cycle_ms: 100
            receivers: [vcu]
            signals:
              - {name: pack_voltage, byte: 0, encoding: float, unit: V, min: 0, max: 1000}
              - {name: pack_current, byte: 4, encoding: float, unit: A, initial: 0}
      - name: vcu

The examples cover each protocol: minimal.yaml (every kind of signal in one CANopen frame), j1939.yaml, canopen-node.yaml (PDOs mapped to CiA 402 objects), vehicle-can.yaml (explicit IDs, CAN FD, multiplexing) and tractor/ (a map in two files).

Documentation

• Map format: every field, the rules, included files, versioning.
• Command line: commands, validation, generated code, document customization, DBC import.
• Web editor: the app, browser mode and its security, keyboard shortcuts, HTTP API.
• VS Code extension: features, settings, commands.
• PDF templates: ESKD/GOST details, logos, fonts, custom templates.
• CI: validating maps and building outputs in a pipeline.
• Contributing and Architecture: setup, tests, releases, how the code is organized.

Roadmap

The 1.0 milestone holds what comes before the format is declared stable. Next is a live bus: adapters, log decoding and replay, a monitor of signal values and a simulator (dashboard issues). Ideas and bug reports are welcome in issues.

License

mapcan is free and open source under the Apache License 2.0, copyright 2026 Ali Ordu (NOTICE). Files generated from your map (code, DBC, documents) are yours to use under any terms, including closed-source firmware. The format specification is under CC BY 4.0, and the JSON Schema and the examples under CC0 1.0: anyone may build tools for the format. Bundled components are listed in THIRD_PARTY_NOTICES.md.

If mapcan helps your project, a star or a citation (CITATION.cff) is much appreciated.