Compare
Outline vs Viaduct
Team knowledge base wiki, not visual C4 modeling with AI
OutlineFast team knowledge base and wiki
ViaductViaduct is a free C4 modeling tool for software teams, with a hosted MCP server that feeds your…Which to pick
Pick Outline if you want…
- Realtime collaborative knowledge base
- Fast team knowledge base
- Open-source code (outline/outline on GitHub)
- Integrations with Slack, Figma or Loom (on Outline's list, not Viaduct's)
Pick Viaduct if you want…
- C4 architecture modeling with AI integration
- A free plan to start with (Browser (free))
- Integrations with Cursor, Claude Code or Claude Desktop (on Viaduct's list, not Outline's)
Side by side
- What it is
- Outline:Outline is a fast, collaborative team knowledge base with markdown editing, real-time collaboration and AI-powered search.
- Viaduct:Viaduct is a free C4 modeling tool that lets software teams create, share, and sync architecture models with AI agents via a hosted MCP server.
- Best for
- Outline:Realtime collaborative knowledge base
- Viaduct:C4 architecture modeling with AI integration
- Who it’s for
- Outline:Teams that need internal documentation, wikis, and shared knowledge.
- Viaduct:Software teams that need collaborative architecture modeling and AI-assisted documentation.
- Pricing
- Outline:Paid
- Viaduct:Freemium
- Plans
- Outline:1-10 members $10 per month per month · 11-100 members $79 per month per month · 101-200 members $249 per month per month
- Viaduct:Browser (free) €0 · Desktop licence €10 per month
- Open source
- Outline:Yes, 40,778 GitHub stars
- Viaduct:—
- Works with
- Outline:Slack, Figma, Loom, Zapier, Open API
- Viaduct:Cursor, Claude Code, Claude Desktop, GitHub, GitLab, Google
Outline features
- Intuitive markdown editor. Blazing-fast editor with markdown, slash commands and interactive embeds.
- Realtime collaboration. Multiple users can edit together with comments and threads.
- AI question answering. Search across docs and ask questions to get direct AI answers.
- Slack integration. Search, share and ask questions from Slack; receive update notifications.
- Public & private sharing. Share docs via link or restrict access, with custom branding and domains.
- Security & permissions. Granular read/write permissions, groups, guest users and audit logs.
Viaduct features
- Full C4 modeling. Create system context, container, component and code diagrams in one editor.
- Hosted MCP server. Provides a machine-readable context for AI agents to read and write architecture data.
- Live collaboration. Team projects with change sets and real-time sharing.
- AI assistant. Generates missing descriptions, names, and reviews model elements for you.
- Desktop app. Native app with local MCP server, offline work and JSON file storage.
- Import/Export. Import OpenAPI specs and export models or contracts as JSON or OpenAPI.
Outline vs Viaduct FAQ
Is Outline or Viaduct free?+
Outline is paid, from $10/month (1-10 members), with a free trial. Viaduct has a free plan (Browser (free)); paid plans start at €10/month (Desktop licence).
Which is cheaper, Outline or Viaduct?+
Outline starts at $10/month (1-10 members) and Viaduct starts at €10/month (Desktop licence); the plans are billed differently, so compare what's included.
Is Outline or Viaduct open source?+
Outline is open source (outline/outline on GitHub). DevHunt has no public source repository on record for Viaduct.
Do Outline and Viaduct integrate with the same tools?+
Their integration lists don't overlap: Outline lists Slack, Figma, Loom, Zapier and 1 more; Viaduct lists Cursor, Claude Code, Claude Desktop, GitHub and 2 more.
On DevHunt
Based on each tool's website and DevHunt data. Details may change; check the official sites.