MapleSpire – Open-source C4 architecture modelling, offline-first

MapleSpire has published its C4 architecture modelling tool as open source under the AGPL-3.0 license at github.com/MapleSpire/maplespire, offering a shared model in which every object and relationship exists exactly once and all views update from it. The tool is self-hostable via Docker Compose with PostgreSQL and Redis, supports real-time and offline editing with sync, and keeps tags and technologies in organization-wide catalogs with a lifecycle of active, deprecated and retired; it adds OIDC single sign-on with Google or Microsoft, role and team grants per landscape, and draft-review-merge with conflict detection. MapleSpire's own comparison grid, checked against official product pages on August 2, 2026, positions it against IcePanel (free tier of 5 editors and 100 objects, Growth at US$40 per editor per month, no offline or self-hosted option), Archyl and Structurizr, and notes that self-hosted sync currently runs as a single instance.

Central tags Tags and tag groups are defined once for the whole organization. Renaming, recoloring, merging or archiving a tag applies to every object that carries it, across every landscape. C4 modeling · open source MapleSpire replaces diagrams that drift out of date with one shared model: every object exists once, every view reflects it, and tags and technologies are managed in one place for the whole organization. 01The model Every object and relationship exists exactly once. Diagrams reference them, so renaming a service or fixing a dependency updates every view it appears in. 02The system Systems, containers, components and dependencies read at a glance, then open up to the level of detail each conversation needs. 03Collaboration Edit together in real time or keep working offline: your changes sync as soon as the network is back. Product tour From a system description to a living C4 model: AI, connected views, offline editing, decision records, drafts, collaboration, MCP and 3D. Governance In drawing tools and DSLs alike, tags and technologies are free text, copied from element to element and repository to repository. MapleSpire keeps them in organization-wide catalogs, so a fix made in the right place applies everywhere. Technologies come from a managed catalog with aliases, icons and a lifecycle active, deprecated, retired . Each usage records the version in use, and new entries go through submission and approval. Organization roles, teams with read or write grants per landscape that inherit downward, and OIDC single sign-on with Google or Microsoft. Prepare a change in a draft, review the change list, then merge with conflict detection. Per-diagram history, restore points and ADRs complete the audit trail. Open source MapleSpire’s code is published under the AGPL-3.0 license. Host it yourself with Docker Compose, or try the hosted demo first — it is built for evaluation, not production. No per-editor licensing: the software and its demo are free. Public code under the AGPL-3.0 license at github.com/MapleSpire/maplespire. Docker Compose with PostgreSQL and Redis: your data stays on your infrastructure. In short A candid market view Compare MapleSpire with IcePanel, Structurizr, Visio, draw.io and diagram-as-code tools. This grid separates native C4 capabilities from manual work, and centrally governed metadata from free text. | Compare approaches, not just feature lists.. Checked against official product pages on August 2, 2026. | | | | | | | | | | |---|---|---|---|---|---|---|---|---|---| | Product | Approach | C4 support | Connected model | Teamwork | Offline editing | Self-hosting | Source | Public entry point | Best fit · limits | |---|---|---|---|---|---|---|---|---|---| | MapleSpire Our product Official sources GitHub https://github.com/MapleSpire/maplespire | Visual model | Native | Yes | Real time | Yes | Yes | Open source | Free and open source AGPL-3.0 · free hosted demo | Visual C4 on one shared model, with organization-wide tag and technology catalogs, real-time collaboration and offline sync. Self-hosted sync currently runs as a single instance. | | IcePanelOfficial sources Docs https://docs.icepanel.io/core-features/modelling Pricing https://icepanel.io/pricing | Visual model | Native | Yes | Real time | No | No | Closed | Free: 5 editors / 100 objects · Growth: US$40/editor/mo, annual | A mature hosted visual C4 model. The documented product is SaaS; there is no general offline editor or self-hosted edition. | | ArchylOfficial sources Features https://www.archyl.com/features Pricing https://www.archyl.com/pricing | Visual model | Native | Yes | Cloud / platform | No | Enterprise / inquiry | Closed | Free individual plan · paid per editor | C4, architecture-as-code and AI-assisted discovery in one product. On-premise is a higher-tier feature; offline editing is not documented. | | StructurizrOfficial sources Server https://docs.structurizr.com/server Enterprise modelling https://docs.structurizr.com/workspaces/enterprise | Model as code | Native | Yes | Cloud / platform | Yes | Yes | Mixed | Free open-core server and local viewer · licensed binaries for SSO and roles | Precise C4 modelling as code, reviewed in Git. Tags and technologies are free text per element, and the enterprise landscape is regenerated from team workspaces. | | C4 ModelOfficial sources Method https://c4model.com/ Tooling https://c4model.com/tooling | Method / notation | The definition | N/A | N/A | N/A | N/A | N/A | Free method and documentation | The shared vocabulary behind the comparison. It defines abstractions and diagrams, but provides no editor, storage or collaboration itself. | | Microsoft VisioOfficial sources Plans https://www.microsoft.com/en-us/microsoft-365/visio/visio-plans-and-pricing | Drawing canvas | Manual | No | Real time | Yes | No | Closed | In some Microsoft 365 plans · Plan 1 US$5 / Plan 2 US$15 user/mo, annual | Broad business and technical diagramming with Microsoft collaboration. C4 and cross-view consistency remain manual. | | LucidchartOfficial sources Product https://lucid.co/product/lucidchart Pricing https://lucid.co/lucidchart/trial | Drawing canvas | Manual | No | Real time | Limited | No | Closed | Free: 3 docs / 60 shapes · Individual US$9/mo + tax | Polished cloud diagramming and co-editing. Offline is limited to previously opened documents and it is not a C4 model. | | CreatelyOfficial sources Plans https://creately.com/plans/ Plan details https://creately.com/help/account-management-and-administration/creately-plans/ | Drawing canvas | Manual | Partial | Real time | Limited | Enterprise / inquiry | Closed | Free: 45 items/workspace · paid plans | A flexible visual workspace with data-backed objects and collaboration. C4 semantics and cross-view architecture rules are manual. | | SmartDrawOfficial sources FAQ https://www.smartdraw.com/about/official-smartdraw-faq.htm Pricing https://www.smartdraw.com/buy/index.htm | Drawing canvas | Manual | No | Real time | No | No | Closed | Free trial · Individual US$9.95/mo, annual | Template-rich technical drawing with real-time multi-user editing. It requires an internet connection and has no free plan. | | draw.io / diagrams.netOfficial sources About https://www.drawio.com/docs/about/ Offline https://www.drawio.com/docs/manual/editor/offline/ | Drawing canvas | Manual | No | Cloud / platform | Yes | Yes | Open source | Free core editor · paid Atlassian integrations | Excellent free, open and offline drawing control. C4 diagrams are drawings, so repeated elements and views must be reconciled manually. | | Excalidraw / Excalidraw+Official sources Pricing https://plus.excalidraw.com/pricing Source https://github.com/excalidraw/excalidraw | Whiteboard | Manual | No | Real time | Limited | Editor only | Mixed | Free editor · Plus US$6/user/mo | Fast, human sketches and collaborative workshops. The editor is open source, while Plus is hosted; neither is an architecture model. | | Archi + coArchiOfficial sources Archi https://www.archimatetool.com/ Plugins https://www.archimatetool.com/plugins/ | EA model | Mapping / add-on | Yes | Git workflow | Yes | Local + Git | Open source | Free | Strong free ArchiMate modelling with Git-based coArchi collaboration. C4 requires a mapping or add-on and collaboration is not live co-editing. | | MermaidOfficial sources C4 syntax https://mermaid.js.org/syntax/c4.html Docs https://mermaid.js.org/intro/ | Diagram as code | Experimental | No | Git workflow | Yes | Yes | Open source | Free open source · optional Mermaid Chart plans | Convenient diagrams inside Markdown and code review. Its C4 syntax is officially experimental and each diagram remains separate. | | PlantUML + C4-PlantUMLOfficial sources C4 library https://github.com/plantuml-stdlib/C4-PlantUML PlantUML https://plantuml.com/ | Diagram as code | Strong library | No | Git workflow | Yes | Yes | Open source | Free open source | Mature C4 diagrams in repositories and documentation. It is a drawing library, not a connected visual architecture model. | | D2Official sources Docs https://d2lang.com/ | Diagram as code | No native C4 | No | Git workflow | Yes | Yes | Open source | Free open source · optional commercial tooling | Readable, fully offline architecture-as-code with strong automatic layout. It has no native C4 semantics or built-in live collaboration. | Prices are public list prices in USD where available, before tax. “C4 Model” is a method, not software. Plans change: follow the descriptively labelled official sources in each row. Contact A system to model, a team to equip, a self-hosting project or a migration from Structurizr: write to us and we will get back to you directly.