Description
DiagramPreview is an online diagram preview and conversion workspace for developers, product teams, architects, and technical writers who need to check diagrams before they land in documentation, tickets, pull requests, or incident reports. It renders text and structured data into visual previews that are easy to inspect, share, and export, keeping the source visible next to the preview.
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The workspace supports many developer-oriented formats, including Mermaid, PlantUML, Markdown, Graphviz, D2, Draw.io XML, mind maps, JSON, and YAML, and it can convert between them, such as turning Mermaid or PlantUML into editable Draw.io XML. It also visualizes schemas and contracts like JSON Schema, Protobuf, GraphQL, SQL, DBML, and Prisma, and turns OpenAPI, Postman, and HAR traffic into sequence and error-flow diagrams for backend review.
Beyond diagrams, it includes a large set of single-purpose utilities for DevOps and config, such as visualizing Docker Compose, Terraform, CloudFormation, Kubernetes manifests, GitHub Actions, and Helm values, plus AI-assisted generators that create Mermaid, PlantUML, and Draw.io from natural language or notes.
Most rendering runs locally in the browser to keep drafts fast and private, while AI-assisted generators use a server-side API so provider keys are not exposed. Supported renderers export SVG, PNG, and print-style PDF from the workspace toolbar.
- CategoryCoding & Development
- Pricing ModelFree
- DeploymentCloud
- PlatformsWeb
DiagramPreview's Core Features
Live preview of Mermaid, PlantUML, Graphviz, D2, and Draw.io diagrams
Conversion between Mermaid, PlantUML, and editable Draw.io XML
Schema visualization for JSON Schema, SQL, DBML, GraphQL, and Prisma
API sequence and error-flow diagrams from OpenAPI, Postman, and HAR
DevOps config visualizers for Docker, Kubernetes, Terraform, and GitHub Actions
AI-assisted generation of diagrams from natural language or notes
Browser-first rendering that runs locally where possible
Export to SVG, PNG, and PDF from the toolbar
How to use DiagramPreview?
Pick a tool: Choose a preview or converter such as Mermaid Preview or Mermaid to Draw.io.
Paste your source: Add your diagram text, schema, API contract, or config.
Preview: Review the rendered diagram next to the source and fix any syntax issues.
Convert if needed: Move between formats such as Mermaid to editable Draw.io XML.
Export: Ship SVG, PNG, or PDF into READMEs, pull requests, or architecture docs.
DiagramPreview's Use Cases
- AI Mermaid review
- API debugging
- Schema visualization
- DevOps config review
- Documentation prep
