Best Tools for Technical Design Docs and RFCs in 2026
The technical design doc is where an engineering team decides how to build something before committing to it. Done well, it surfaces risks, gets the right reviewers involved early, and leaves a record of why the system looks the way it does. Done poorly, it is a doc written after the code, reviewed by nobody, and never opened again.
The tool matters less than the habit, but it still matters. We evaluated these options on writing experience, review and commenting workflow, support for diagrams and code, discoverability months later, and how well the doc connects to the product spec upstream and the tickets downstream.
Have a feature in mind? Describe it and Vantage drafts the PRD.
A few sentences is enough: the problem, who has it and what you want to change. Vantage turns it into a structured PRD with requirements you can edit.
How this works
- We save what you typed. No AI runs on this page.
- You create a free account.
- Vantage builds a PRD from it inside your own workspace.
Why ask for an account? We’re a small team, and a full generation runs a multi-step AI pipeline that costs us real money. So we tie it to a free account instead of running it anonymously. You also get to keep the result and edit it.
Your text is only used to create your project, and it stays private to your account. If you don’t sign up, we delete it after 7 days. Privacy policy
Notion
Flexible docs with databases for an RFC index
Notion is the most common home for design docs at product-led companies. Teams typically create an RFC template and a database that tracks status, author, reviewers, and decision date, which makes past decisions searchable. Inline comments, code blocks, and embedded diagrams cover most design doc needs, and Notion AI helps with summaries and search.
Pros
- Database view turns RFCs into a searchable decision log
- Flexible templates and inline comments
- Embeds for diagrams, Figma, and code
- Familiar to product and design as well as engineering
Cons
- No native link to code or PRs
- Approval workflows are informal
- Large workspaces get hard to navigate without discipline
Confluence
The default doc system for Jira shops
Confluence offers design doc and decision templates out of the box and links tightly with Jira, so a design doc can reference the epic and the epic can link back. Page trees, permissions, and space organization suit larger engineering orgs, and Atlassian's AI features help summarize long docs and comment threads.
Pros
- Tight Jira integration for traceability
- Built-in templates for design docs and decisions
- Granular permissions and space structure
- Mature inline commenting
Cons
- Editing experience feels heavier than modern editors
- Search quality varies with page sprawl
- Docs go stale without ownership
GitHub (docs as code)
RFCs as markdown files reviewed through pull requests
Many infrastructure-heavy teams keep RFCs as markdown files in a repository and review them through pull requests. Review happens line by line with the same tools engineers use for code, history is versioned, and the doc lives next to what it describes. Mermaid diagrams render natively in GitHub markdown.
Pros
- Line-level review using familiar PR workflow
- Full version history and clear approval record
- Docs live alongside the code
- Mermaid diagrams render natively
Cons
- Hostile to non-engineering reviewers
- Harder to browse than a wiki
- Rich media and embeds are limited
Google Docs
Frictionless writing and suggestion-mode review
Google Docs remains a strong option for design docs because of its commenting and suggestion mode, which make asynchronous review easy for anyone in the company. Its weakness is organization: without a deliberate index, design docs scatter across personal drives and become impossible to find later.
Pros
- Excellent commenting and suggestion mode
- Everyone already knows how to use it
- Real-time co-editing
- Easy to share outside engineering
Cons
- No structure for indexing or tracking status
- Docs get lost in personal drives
- Weak code and diagram support
Eraser
Design docs with diagrams-as-code built in
Eraser combines a doc editor with a diagramming canvas and diagram-as-code syntax, aimed specifically at technical design. You can generate architecture, sequence, and entity-relationship diagrams from text or AI prompts and keep them next to the prose that explains them. It integrates with GitHub so diagrams can be kept in sync with the repo.
Pros
- Diagrams and docs in one place
- Diagram-as-code makes diagrams easy to update
- AI generation for architecture and sequence diagrams
- Designed specifically for engineering design
Cons
- Smaller ecosystem than general doc tools
- Less suited to non-technical documents
- Another tool to add alongside your wiki
Vantage
Keeps the design doc connected to the PRD and the codebase
Vantage is not a general wiki, but it addresses a common design doc problem: the technical plan drifts from the product spec. In Vantage, the PRD, requirements, and project documents live together, and connecting GitHub lets the query engine answer questions about the current codebase while the doc is being written. Requirements then become dependency-aware tickets, so the plan, the spec, and the backlog stay linked.
Pros
- Design docs sit alongside the PRD and requirements they implement
- Query the codebase via GitHub while writing
- Requirements flow into dependency-aware tickets
- Version history and diffs on documents
Cons
- Not a full RFC system with formal approval flows
- Diagramming is limited compared to dedicated tools
- Most valuable when the PRD also lives in Vantage