Free browser-based diagramming tools - flowcharts, mind maps, ER diagrams, UML class and sequence diagrams, network graphs, Gantt charts, function plotters, and freehand drawing boards. All tools run in the browser: no account required, no Lucidchart or draw.io subscription needed for basic use. Export diagrams as PNG, SVG, or Mermaid/PlantUML syntax for embedding in Markdown documentation. The ER Diagram tool generates CREATE TABLE SQL from your schema design. The Gantt Chart tool produces shareable project timelines.

When to use Diagrams

1Database design: use the ER Diagram tool to plan entity relationships, define primary and foreign keys, and generate the CREATE TABLE SQL before writing any application code.
2Software architecture: create UML class diagrams for documenting object models, sequence diagrams for API flows, and component diagrams for system overviews.
3Project planning: build a Gantt chart with tasks, durations, dependencies, and assignees - export as PDF for stakeholder presentations.
4Brainstorming: start a mind map from a central concept, branch out with ideas, and colour-code by theme - without needing a Miro or Figma account.
5Documentation: create a flowchart or diagram and export as Mermaid syntax to embed directly in GitHub README files, Notion pages, or Confluence.

Frequently Asked Questions

What is Mermaid syntax and why would I export to it?+

Mermaid is a text-based diagramming language where you write diagram descriptions in a simple syntax that renders as images. It is natively supported in GitHub README files, GitLab, Notion, Confluence, and many documentation platforms. Exporting your diagram as Mermaid lets you embed it as living, version-controlled text rather than a static image.

How do I create a database schema diagram?+

Use the ER Diagram tool. Add entities (tables), define their attributes with data types (VARCHAR, INT, DATE), mark primary keys, and draw relationship lines between entities. Set cardinality (1:1, 1:N, M:N) on each relationship. Click 'Generate SQL' to export CREATE TABLE statements for your chosen database dialect.

What UML diagram types are available?+

Class diagrams (showing classes, attributes, methods, and relationships), Sequence diagrams (showing object interactions over time), Use Case diagrams (actor-system interactions), Activity diagrams (decision flowcharts), State Machine diagrams (state transitions), and Component diagrams (system architecture and dependencies).

Can I use these tools for client presentations?+

Yes. Export any diagram as SVG for infinite-resolution vector output, or PNG for direct use in presentation slides. Gantt charts can be exported as PDF. Mind maps export as PNG or SVG. For interactive presentations, embed Mermaid diagrams in Notion or Reveal.js slides.

About Diagrams

When to use Diagrams

1Database design: use the ER Diagram tool to plan entity relationships, define primary and foreign keys, and generate the CREATE TABLE SQL before writing any application code.

2Software architecture: create UML class diagrams for documenting object models, sequence diagrams for API flows, and component diagrams for system overviews.

3Project planning: build a Gantt chart with tasks, durations, dependencies, and assignees - export as PDF for stakeholder presentations.

4Brainstorming: start a mind map from a central concept, branch out with ideas, and colour-code by theme - without needing a Miro or Figma account.

5Documentation: create a flowchart or diagram and export as Mermaid syntax to embed directly in GitHub README files, Notion pages, or Confluence.

Frequently Asked Questions

What is Mermaid syntax and why would I export to it?+

How do I create a database schema diagram?+

What UML diagram types are available?+

Can I use these tools for client presentations?+