Gleek

Free covers the whole diagram syntax but caps the output. The pricing FAQ limits it to 5 diagram files and 40 objects in each, one export format (PNG), no styling changes, no support and ads. The bigger catch is storage: Free diagrams live only in the browser’s IndexedDB database. Editorial assessment: that makes a Free diagram tied to one browser profile, so clearing site data or switching computers can leave it behind; export the PNG and keep the source text somewhere safe.

An older getting-started guide from 2020 still describes an SVG download button. The current pricing page lists SVG and PDF only on paid plans, and that is the condition to plan around.

Each line of text becomes part of the drawing. Typing a name and a colon opens autocomplete for shape types such as actor, class, db, diamond, note, oval, queue and service; any other word becomes a plain rectangle. An arrow is typed as two names joined by an arrow, and a label sits inside the arrow. Pressing Tab nests attributes inside a class or entity, which is how class and ER diagrams list their fields. Templates fill the code field with a starter diagram from a right-click menu.

Gleek moved to a layout engine based on Mermaid in a 2020 update, so the program places shapes for you and you do not drag them. For databases, the ER diagram page covers both Chen and Crow’s Foot notation. If your starting point is ordinary prose rather than syntax, Napkin AI builds diagrams from pasted text on its free plan.

The AI chat launched in August 2023 and is limited to paid plans. You describe a diagram, from a simple “ER diagram with three entities” to a prompt that names every entity and its one-to-many relationships, and the chat writes the Gleek code. The result opens in code mode, so you can add details or change the diagram type by editing text.

The April 2025 update added Gantt charts to the AI, a chat history saved with each diagram and iterative edits where you ask the AI to extend an existing diagram. Neither the terms nor the privacy policy name the AI model or provider, so anyone who must not send system designs to an outside service should ask before typing them in.

All four paid options unlock the same features. Premium Monthly is the flat €6.95. Premium Yearly is one €58.40 charge. Per Activity costs more per month, €10.99, but pauses billing after a month in which you did not use Gleek, according to the Per Activity announcement. The pause is not instant: a month you were active triggers a charge for the following month, and only after that idle month do charges stop until you log in again.

• Steady weekly use: Yearly.
• A few projects a year with gaps of several months: Per Activity.
• A single short project: Monthly, cancelled before the next billing date.

Paid diagrams are stored on Gleek servers, or in your own repository once you connect it. The Git announcement from 2019 describes .gl files in a gleeks folder, a Push button in the editor, a pull every 5 minutes to pick up changes and conflict resolution inside the editor. It also says requests to GitHub, GitLab and Bitbucket go through a passthrough proxy, while Azure DevOps, Gitea and Gogs connect directly.

On the Team plan, whoever pays becomes the owner. The owner invites members by email, can change the number of seats or cancel, and gets one invoice. The owner’s own account stays on Free unless they invite themselves too.

1. Open app.gleek.io and write an ER diagram with 5 entities and 4 attributes each, in Crow’s Foot notation.
2. Note whether the editor warns as the diagram approaches 40 objects.
3. Export a PNG and check that every label is readable at full size.
4. Open the same account in a second browser and see whether the diagram appears.

Accept if the diagram fits under the object limit and the PNG is legible. Reject if attributes count toward the 40 objects so the diagram cannot be finished on Free. No result is recorded here.