Best Diagram Software

Visual Paradigm is a diagramming and modeling platform built around UML 2.x, supporting all 13 standard UML diagram types alongside BPMN and ArchiMate. It includes AI Diagram Generation and an AI chatbot that can create UML diagrams from plain English descriptions, plus Round-Trip Engineering that generates source code in Java, C#, or Python from class diagrams and can reverse-engineer existing codebases back into diagrams. A free Community Edition supports non-commercial use.

The desktop product is sold in Modeler, Standard, Professional, and Enterprise editions, available as monthly or quarterly subscriptions or as one-time perpetual licenses with a year of maintenance included. Visual Paradigm Online extends the same modeling capabilities into a browser-based platform. Volume discounts apply for teams buying five or more licenses.

LibreOffice Draw is a free, open source vector graphics and diagramming application that is part of the LibreOffice office suite from The Document Foundation. It can produce anything from simple flowcharts and org charts to complex illustrations, using shape, polygon, Bezier curve, and connector tools, along with a library of premade flowchart and diagram shapes. Draw supports batch operations and a master page concept for consistent, reusable layouts.

Files can be imported and exported in formats including SVG, PDF, PNG, and Microsoft Visio (VSD), and diagrams created in Draw can be inserted directly into LibreOffice Writer documents or Impress presentations. LibreOffice Draw runs on Windows, macOS, and Linux, and is licensed under the Mozilla Public License 2.0 with no paid tiers, subscriptions, or feature restrictions.

PlantUML is a free, open source tool that creates diagrams from plain text descriptions rather than manual drag-and-drop editing. It covers the full range of UML diagrams, including sequence, use case, class, activity, component, deployment, and state diagrams, as well as non-UML formats like Gantt charts, mindmaps, wireframes, and entity relationship diagrams. Multiple layout engines, including Graphviz, Smetana, and ELK, arrange diagram elements automatically.

Diagrams can be rendered in a browser, generated through a self-hosted server, or produced from the command line, and exported as PNG, SVG, LaTeX, EPS, or ASCII art. Because diagrams are plain text .puml files, they integrate naturally with Git for version control and code review. PlantUML is free and open source, though a Professional Edition license can be requested to remove occasional sponsor messages.

draw.io, also published as diagrams.net, is a free diagramming application built by JGraph Ltd that runs as a web app or a downloadable desktop program for Windows, macOS and Linux. It requires no account or login, supports flowcharts, UML, ER diagrams, BPMN, network diagrams and floor plans, and stores files in the location the user chooses, such as Google Drive, OneDrive, Dropbox or GitHub.

The core application is entirely free with no feature restrictions. JGraph separately sells Confluence and Jira Cloud apps that embed draw.io diagramming inside Atlassian products, priced per user with volume discounts for larger teams and custom pricing for enterprise scale deployments.

Miro is a cloud based visual workspace used for brainstorming, diagramming, wireframing and project planning on an infinite canvas. Teams use it for sticky note brainstorms, flowcharts, journey maps and product planning, with real time cursors, comments, voting and timers to run workshops and meetings directly on the board.

Miro AI can generate flowcharts, UML diagrams and entity relationship diagrams from text prompts and can cluster sticky notes by theme. The platform connects with more than 250 tools including Jira, Asana, Slack and Microsoft Teams, and includes SSO, audit logs and SOC 2, GDPR and PCI compliance for larger organizations.

Mermaid is an open source JavaScript library that generates diagrams and charts from a simple, Markdown-inspired text syntax. It supports flowcharts, sequence diagrams, class diagrams, entity relationship diagrams, Gantt charts, state diagrams, mindmaps, and git graphs, and can be embedded in documentation, wikis, and developer tools. The core library is MIT licensed and free to use, self-host, or embed in other applications.

Alongside the open source library, Mermaid Chart is a commercial platform built by the project's creators that adds a visual drag-and-drop editor, AI-assisted diagram generation, team collaboration, and hosted storage. Mermaid Chart offers a free Basic plan with a limited number of diagrams, plus paid Plus, Premium, and Enterprise plans for teams that need unlimited diagrams, SSO, and centralized billing.

SmartDraw is diagramming software known for its intelligent formatting engine that automatically arranges shapes and connectors as diagrams are built. It includes more than 34,000 symbols and thousands of templates covering flowcharts, org charts, floor plans, network diagrams and engineering drawings, and can generate diagrams automatically from data such as org chart spreadsheets or AWS and Azure architectures.

SmartDraw is available as a web application and as desktop software for Windows and Mac, with real time collaboration and Visio import and export. It is sold on Individual and Team subscriptions billed annually, plus a custom priced Enterprise plan with SSO and dedicated support, and there is no permanent free plan.

Gliffy, owned by Perforce, is a diagramming tool best known as an app for Atlassian Confluence and Jira that lets teams build flowcharts, UML diagrams, network diagrams and BPMN charts with a drag and drop editor. Diagrams embedded in Confluence pages are fully searchable, and the tool supports real time collaborative editing, permission management and AI assisted diagram generation.

Gliffy for Confluence is free for teams of up to 10 users, with paid tiers priced per user for larger teams and a Zero Egress option for government and compliance focused customers. A 30 day free trial is available, and Data Center licenses are sold as perpetual licenses with included maintenance.

Whimsical is a visual workspace built for product teams to create flowcharts, wireframes, mind maps and documents in one place. It emphasizes speed and a clean interface, with AI powered diagram generation that turns a text prompt into an editable flowchart, plus real time collaboration, comments and customizable templates.

Whimsical offers a free plan limited to 3 team boards and 10 guests, along with Pro and Business subscriptions billed monthly or annually. The Business plan adds SSO, SCIM provisioning and workspace lockdown controls for larger organizations, and Whimsical provides discounts for nonprofits and free access for verified students and teachers.

OmniGraffle is a diagramming and vector illustration application from The Omni Group, built specifically for Mac, iPhone, and iPad. It is used for diagramming, rapid wireframe prototyping, and general vector design, with smart guides, auto layout, and Bezier and orthogonal line tools. Every object created is a scalable vector shape, and the app integrates with macOS features like Dark Mode, iCloud sync, and Apple Silicon.

OmniGraffle is sold as separate Standard and Pro perpetual licenses for Mac and for iOS, or as a cross-platform Pro subscription covering both. There is no free plan, but a free trial is available before purchase. Diagrams can be exported to PDF, SVG, PNG, and other common formats for sharing outside the app.