Sankey Diagram Maker (Free Image Generator)

A sankey diagram maker turns a list of flows into a single image where each band's width matches its value, so the big paths and the leaks jump out. Enter your source, target, and value rows, pick colors, and download a PNG or SVG you can drop anywhere.

What a sankey diagram showsWhat a sankey diagram shows

A sankey diagram, named after the engineer who used one to chart steam-engine energy loss in 1898, tracks where a quantity goes as it moves and splits. One value flows in on the left, branches through nodes, and lands on the right, and the width of every band is proportional to how much flows through it. That's the whole idea: you read volume by thickness, not by squinting at numbers.

It's a great fit when the story is about proportion and routing:

• Budgets: total income on the left, then salaries, rent, tools, and savings fanning out on the right. You see instantly what eats the money.
• Traffic and conversions: sources like search, social, and referral flowing into signups, then into paid, then into churn. The narrow bands are your drop-off.
• User journeys: entry pages splitting into the paths people actually take, so dead ends are obvious.

One rule keeps it readable: keep it acyclic. Value should move forward through stages and never loop back into an earlier node, or the widths stop making sense.

Make one freeMake one free

Open the sankey diagram maker and enter your flows. Each row is a source, a target, and a number: "Revenue → Payroll, 42000", "Revenue → Rent, 9000", and so on. The tool lays out the nodes, sizes the bands to your values, and lets you pick colors for each flow or node.

No signup, no watermark. When it looks right, download it as a PNG for slides and docs, or SVG if you want crisp scaling on the web. That's the fastest path from a spreadsheet column to a chart you can share.

Embed it anywhereEmbed it anywhere

A sankey diagram is just an image, so embedding it is a one-liner. Point an image tag at the chart URL and you're done:

<img
  src="https://render.imejis.io/v1/YOUR_DESIGN_ID?dma-api-key=YOUR_API_KEY&node.label=Revenue&flow.value=42000"
  alt="Budget flow sankey diagram"
/>

The design ID goes in the path, and your API key plus any field overrides ride along as query params. Each field is a flat component.property pair, so node.label and flow.value set the node name and the band size right from the URL. It returns a JPEG by default. Add ?format=png or ?format=webp if you want lossless output, or ?format=pdf for print.

The useful trick is what the URL points at. Because the image regenerates every time the page loads, when your budget or your funnel numbers change, the chart updates on its own. Same embed line, live data.

Generate at scaleGenerate at scale

One flow chart is a tool job. Fifty of them, or one that has to stay current, is an API job. Sankey is an API component, so a single render call turns a set of flows into a finished image, no design tool in the loop.

That opens up a few ways to run it:

• From code: POST your source, target, and value rows to https://render.imejis.io/v1/YOUR_DESIGN_ID with a dma-api-key header and get an image back. The body is flat component.property pairs, like { "node.label": "Revenue", "flow.value": 42000 }. The API docs have tested examples you can paste and run.
• From an agent: hand the job to an AI agent over MCP. It reads your data, builds the flows, and renders the chart without you writing the request by hand.
• From a template: design the sankey once and swap the data per render, so one setup covers every report, client, or month.

See the sankey component for the fields it accepts and how to shape your flow data.

Start buildingStart building

Make a quick one in the sankey diagram maker, then wire up the sankey component when you want charts that build themselves. Point a script at the API or let an AI agent handle it. Pricing starts with a permanent free tier: 100 renders a month, which is plenty to see your flows turn into images before you scale up.