If you are looking for a free online diagram or drawing tool, then draw.io will be useful. It doesn’t even need any sign-up or login to start using it.

The drawings created using draw.io are free to use and distribute. Also there are no functional limitations although it’s free. It however does have pricing plans that are geared for enterprise users, the details of which can be found here.

Go to draw.io to start using it through any web browser.

The initial screen will prompt for a either opening an existing drawing or making a new one.

You can also change where the drawings will be saved by clicking on Change storage.

draw.io supports online storage like OneDrive, Google Drive and also local paths.

When a new diagram is chosen, there will be a list of categories to choose from. You can also choose a tenplate link to load it from there.

Click Create after selecting the required diagram category.

The main interface of draw.io is fairly simple.

One the left are various items like scratchpad, drawing shapes, miscellaeneous symbols, advanced shapes and other additional drawing elements depending on the drawing.

The center area is the canvas where you can create drawings and the right pane is the properties editor for various selected shapes and elements.

You can also add common drawing elements like shapes, text and more by directly by clicking the + icon from menu bar.

Also, draw.io has a cool search feature when looking for various shapes.

Simply enter the shape and a list of related results will be displayed.

Scratchpad is a useful timesaver as you can keep commonly used shapes from drawings over there. So it is like a shortcut to access common drawing shapes quickly.

To keep these shapes and elements, drag them from the canvas area to scratchpad. They will then be visible there. To add them back to canvas area, drag-drop them again from scratchpad.

You can also manage the shapes in scratchpad. Click the pencil/edit icon.

Then rearrange the order of shapes in scratchpad or delete the ones that are no longer needed.

To add various shapes and diagram elements to drawings, simply drag and drop them from the left pane to the canvas area on right.

Choose different arrows, advanced shapes, text based list and so on as needed for the drawing.

To edit shapes, choose the properties to be changed from the right pane. Also, to delete them, right click and select Delete.

To add more shapes depending on the drawing, click on More Shapes from the bottom left pane.

It will bring up a list of shapes for various types of drawings. Select as needed.

There are useful keyboard shortcuts for draw.io that can make it lot quicker to create and edit diagrams. The complete list of that can be found here or can be accessed from the menu (Help > Keyboard Shortcuts).

Diagrams can be exported to various formats like PNG, JPEG, SVG, PDF and more by choosing File > Export as.

Similarly, you can import existing drawings from OneDrive, Google Drive, Dropbox, Github, Trello and so on by choosing File > Import from.

Another useful feature is that you can share these drawings directly via link. To publish a link for a drawing, select File > Publish> Link.

Choose the appearance as well as other link display details and hit Create.

The link to the drawing will be generated.

You can then directly share the link details through Facebook, Twitter or copy paste it in emails.

Overall, this is a detailed online drawing tool for making various diagrams including flowcharts, graphs, network diagrams and so on.

Do try it out.