Generate complete system design document
AI writes 10-page architecture design doc with technical details and diagram descriptions.
Generate complete system design document
River's System Design Document Generator creates comprehensive architecture documentation from your system description. You provide the high-level architecture, components, and technical stack, and the AI writes complete design documentation including system overview, component architecture, data flow, technology choices, scalability considerations, security measures, and deployment strategy. Whether you're designing new systems, documenting existing architecture, or planning technical migrations, you get professional design docs that guide implementation.
Unlike high-level diagrams alone, we create detailed specifications. The AI understands system design principles (separation of concerns, scalability patterns, fault tolerance, security best practices), explains architectural decisions and tradeoffs, and structures information for engineering teams. You get design docs that answer implementation questions and provide clear technical direction.
This tool is perfect for solutions architects designing systems, engineering leads documenting architecture, technical teams planning major features, and organizations standardizing design documentation. If you have architecture in mind but need formal documentation, or if you want to improve technical specifications, this tool helps. Use it when planning systems to ensure team alignment on technical approach.
What Makes System Design Docs Effective
System design documentation succeeds when it guides implementation decisions and prevents architectural mistakes. Effective design docs start with system overview (what we're building, why this architecture), define components clearly (responsibilities, boundaries, interfaces), explain data flow (how information moves through system), document technology choices (what and why), address non-functional requirements (performance, scalability, reliability, security), show deployment architecture, and explain tradeoffs made. Weak design docs are vague or focus on tools without explaining decisions. Strong design docs help engineers understand not just what to build but why architectural choices were made.
The best design docs balance detail with readability. Start with context and goals (business requirements driving architecture). Show high-level architecture (major components and relationships). Dive into each component (purpose, responsibilities, interfaces, technology). Document data models and flows. Address scalability, performance, and reliability. Explain security measures. Show deployment architecture. Include diagrams (architecture diagrams, sequence diagrams, data flow diagrams). Note alternatives considered and why rejected. This structure helps engineers implement correctly and understand tradeoffs when making detailed decisions.
To improve design docs, involve engineering team early (implementation feasibility matters). Explain why, not just what (rationale helps future decisions). Document alternatives considered (shows thoughtfulness, helps future changes). Address failure scenarios (systems fail, plan for it). Include concrete numbers (requests per second, data volumes, latency requirements). Draw diagrams (visual beats text for architecture). Update as design evolves (living document). Review with security team. Consider operational concerns (monitoring, debugging, deployment). Remember: design doc creates shared understanding. Time spent documenting architecture prevents costly mistakes during implementation. Clear design enables confident, efficient building.
What You Get
Complete 10-page system design document
System overview and architecture diagrams (text descriptions)
Component specifications and interfaces
Data flow and technology stack documentation
Scalability, security, and reliability considerations
Deployment strategy and monitoring approach
How It Works
- 1Describe system architectureProvide components, tech stack, and architectural approach
- 2AI writes complete design docOur AI creates comprehensive architecture documentation in 5 to 7 minutes
- 3Review and refineRead through design, add specific details, create actual diagrams
- 4Share with team and implementDistribute to engineers, use as implementation guide
Frequently Asked Questions
Does this generate actual architecture diagrams?
It generates detailed text descriptions of diagrams you should create. Use tools like draw.io, Lucidchart, or Mermaid to create actual visual diagrams from the descriptions. The AI specifies what diagrams you need and what should be in them. Visual diagrams are essential, but you create them based on provided specifications.
Should design docs include code examples?
Include interface definitions, API contracts, and key algorithms. Full implementation code belongs in code repositories, not design docs. But showing interface signatures, data structures, and critical logic helps engineers understand expectations. Balance: enough code to clarify design, not so much that doc becomes codebase.
How detailed should technology choices be documented?
Document what technology and why you chose it. Explain tradeoffs. ((We chose PostgreSQL over MongoDB because we need ACID transactions and our data is highly relational. We considered MongoDB for flexibility but our schema is stable and consistency is critical)). Future team members need to understand rationale to maintain or change architecture appropriately.
What if the system architecture changes?
Update the design doc and version it. Track major changes. When architecture evolves significantly, create new version documenting changes and rationale. Design docs should reflect current or planned state. Outdated design docs are dangerous. They mislead engineers and new team members. Keep current or clearly mark as historical.
Should I document every microservice separately?
This tool creates system-level overview. Individual services need separate detailed specs. Use this for overall architecture. Then create service-specific docs for each component detailing that service's implementation. Think: this tool documents forest (overall system), you document trees (individual services) separately.
What is River?
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