ER Diagram API
Generate er diagram images with a single HTTP request. ChartQuery returns publication-ready PNG or SVG output that works everywhere, dashboards, emails, PDFs, print, and more. No frontend library required.
Live Preview
This image is generated in real time by the ChartQuery API, no static assets.
Quick Start
A single HTTP request is all you need. No SDK, no dependencies.
curl -X POST https://api.chartquery.com/v1/diagram \
-H "Content-Type: application/json" \
-d '{"diagram_type":"mermaid","diagram_source":"graph TD\\n A[Start] --> B{Decision}\\n B -->|Yes| C[Process]\\n B -->|No| D[End]","output_format":"svg"}' \
--output diagram.svgHow It Works
Send a Request
POST a JSON body or use GET with query parameters. No SDK or library needed.
Get Your Image
ChartQuery renders your chart, diagram, barcode, QR code, or label and returns it as PNG or SVG.
Use It Anywhere
Embed in emails, PDFs, dashboards, documents, or print directly. Works everywhere images work.
Features
28 Diagram Languages
Mermaid, PlantUML, D2, GraphViz, and 24 more, all rendered through one unified API endpoint.
Multiple Output Formats
SVG (default), PNG, JPEG, and PDF output. Choose the best format for your use case.
Text-Based Input
Define diagrams as text, version-control friendly, easy to generate programmatically, and human-readable.
AI-Powered Generation
Describe your diagram in plain English and let AI pick the best language and layout for you.
Use Cases
- Software architecture and documentation
- Process flow and workflow visualization
- Database schema and ER diagrams
- CI/CD pipeline and infrastructure diagrams
Frequently Asked Questions
What is the ChartQuery ER Diagram API?
The ChartQuery ER Diagram API lets you generate er diagram images via a simple HTTP request. Send a JSON configuration and receive a rendered PNG or SVG image in the response. No frontend library, no browser, no dependencies required.
How do I generate a er diagram with an API?
Send a POST request to the ChartQuery diagram endpoint with your data as JSON. The API returns a rendered image directly. You can also use GET requests with URL parameters for simple cases. No API key is required for basic usage, anonymous access is available with 60 requests per hour.
What output formats does the ER Diagram API support?
SVG (default), PNG, JPEG, and PDF. SVG output can be embedded directly in HTML and styled with CSS.
Is the ER Diagram API free to use?
Yes. The ChartQuery ER Diagram API works without an API key. Anonymous access is rate-limited to 60 requests per hour and adds a small watermark. Authenticated users on paid plans get higher limits, no watermark, and longer chart persistence (6 months vs 3 days for shared URLs).
Can I customize the er diagram appearance?
Yes. You have full control over colors, fonts, sizes, backgrounds, legends, and every visual property through the JSON configuration. The API uses Chart.js v4 for charts, and supports all native options for fine-grained customization.
Can I share and embed diagrams generated by the API?
Yes. Add "share": true to any request to get permanent URLs. The render_url is a direct image URL you can embed in emails, documents, or <img> tags. The view_url is an interactive HTML page you can embed as an iframe. No authentication needed for viewers.
Related APIs
Start generating charts today
No API key required to get started. Generate charts, diagrams, and more with a single HTTP request.
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