Code flow diagrams: plan logic visually and export code

Blocks with pins

Every block has input pins on its left edge and output pins on its right. An If block has true and false outputs, a Loop has body and done, and an HTTP Request has success and error. Drag from an output pin to the next block's input pin to decide what runs next.

Name your values

Blocks that produce a value, such as a function call, an HTTP request or a database query, have an "into" field. Type the variable name there and later blocks can read it, just like in code.

Simulate it, or run it for real

Simulate moves a token through the diagram one step at a time. At each branch you choose which path to take, or let it pick automatically, so you can find a missing connection before writing a line of code.

Run code goes further: the blocks really execute as JavaScript. Variables hold values, Math calculates, If and Loop decide and repeat, Input / Output asks you questions, and Parallel branches run side by side. Press Step to run one block at a time while watching the variables change, or Run to let it go. If something goes wrong, the failing block turns red with a plain explanation.

Spot mistakes as you build

Live problem checking marks blocks with errors, warnings and notes while you work: unreachable blocks, loops with no way out, variables that are read before they are set, unclosed brackets, invalid names and more. Click a problem in the list to jump to the block.

Export JavaScript, Python or pseudocode

Use File, then Export as code. NodeFlow walks the diagram from each Start or Event block and writes nested functions, conditions and loops. It warns about blocks that nothing connects to and about variables that are read but never set.

Good for

• Planning an algorithm before coding it.
• Explaining a function or API flow to a team.
• Teaching control flow, loops and error handling.