| What it does | API sequence diagram tool with payloads on every arrow
| Ontological knowledge graph that surfaces specification gaps, test coverage gaps, and unaddressed architecture standards before code ships
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| Stage | Not given
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| Pricing model | Freemium
| Freemium
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| Pricing | Free: editor, local diagrams, share links, SVG and PNG export, CLI, 3 saved diagrams, HAR imports up to 8 requests, 200 hosted API and MCP calls a month, 1 webhook inbox with 25 requests a month, 1 recording link with 3 recordings. Pro: $9/month or $90/year (billed in advance), up to 1,000 saved dia
| Free CLI (MIT + Commons Clause licence, free for own projects including commercial software). Bootstrap Kit $149 one-time per repository (includes 12 months updates, unlimited team members, web visualiser, AI audit commands, architecture standards YAML, Docker setup, and Claude + Kimi Code CLI skill
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| Key features | - Plain-text sequence diagram editor with real-time rendering
- Request and response payloads displayed on every arrow
- HAR file import with automatic redaction of secrets
- Webhook inbox to capture and diagram provider deliveries
- Recording links to collect customer HAR files as diagrams
- Drift Check to update diagrams when APIs change
- SVG and PNG export for sharing and embedding
- AI agent support via MCP server, HTTP API and CLI
- README embeds that update when diagrams are edited
- Presentation mode for step-through walkthroughs
| - Reduced AI orientation tokens (71% fewer on Formbricks codebase)
- Requirements traceability from user stories through use cases to features to tests
- Automated requirement quality checks using 13 QUS criteria and 6 traceability rules without AI API key
- V-model 4-tier test coverage mapping (component, integration, use case flow, end-to-end)
- AI test quality audit across 7 AS-TEST dimensions
- Code scanning for Go, TypeScript, Python, Java, C# with automatic symbol and test linking
- Web visualiser with drill-down graph navigation and entity editor
- Parallel session coordination with in-progress marking
- Docker Compose setup with one-command initialization
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| What makes it different | - No account needed to write and share diagrams
- AI can write diagrams from plain-text syntax
- Built from real traffic: HAR files, webhooks and customer recordings
| - Maps what a system is supposed to do and whether it's verified, not just what code contains or what chats remember
- Surfaces specification gaps that code review cannot detect because the requirement was never written down
- Session start in 30 seconds with three commands replacing ten minutes of manual code reading
- Eliminates duplicate implementations across 12 parallel AI sessions with one shared ontology
- Bootstrap kit ROI in 5 days at 10 sessions/day through orientation token savings
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| Free plan | Not given
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| Open source | Not given
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| Platforms | Not given
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| Public API | Not given
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| Community votes | 0 | 0 |
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| DR (Domain Rating by Ahrefs) | 3 ● no change since last check | Not checked yet ● no change since last check |
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| Trust Flow (Majestic) | 3 | 3 |
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| Citation Flow (Majestic) | 22 | 19 |
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| Referring domains (Majestic) | 8 | 33 |
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SysEdge