AI tool · 1 credit · refunded if it fails

Deneb template generator

Describe the chart, list the fields in your Deneb Values well, and get a Vega-Lite spec that already compiles — with a rendered preview and the steps to paste it into Power BI.

Only need a small graphic in a table cell? The AI SVG measure generator is lighter.

Try an example

One per line, exactly as shown in the Values well. Optionally add a type: Order Date: temporal.

Header = field names; up to 200 rows. The first 5 rows are shown to the AI (Anthropic) as examples; all rows are used to compile and preview the spec. Leave empty and we synthesise rows from the field types — do that for confidential data.

1 credit · refunded if it fails

What you get

  • A Vega-Lite v5 spec bound to Deneb's dataset, using your exact field names, sized to fill the visual (width/height: container) and styled for Power BI.
  • A real preview: the spec compiled and rendered to SVG on sample rows — paste a few rows of CSV to preview with your own values (the first 5 are also shown to the AI as examples).
  • Import steps, including the cross-filtering switch when the spec uses it, and notes on what to tweak.

A sorted bar chart with cross-filter fading looks like this:

{
  "data": { "name": "dataset" },
  "width": "container",
  "height": "container",
  "mark": { "type": "bar", "tooltip": true },
  "encoding": {
    "y": { "field": "Region", "type": "nominal", "sort": "-x" },
    "x": { "field": "Total Sales", "type": "quantitative" },
    "opacity": {
      "condition": { "test": "datum.__selected__ == 'off'", "value": 0.3 },
      "value": 1
    }
  }
}

Deneb rules the generator follows

  • Data is always {"name": "dataset"} — no inline values, URLs or external images, which Deneb would not load anyway.
  • Each row is one combination of your columns plus measures, like a table visual; totals at a coarser grain use aggregates — except in cross-filter specs, where an aggregate would drop __selected__ and the fade would never fire.
  • __selected__ is used only when you ask for cross-filtering, and __row__ is available for row-level tricks.
  • No $schema key, which Deneb strips or warns about when you paste a spec.
  • Segoe UI text, light gridlines and no view border so the chart sits naturally next to built-in visuals.

How to use a generated Vega-Lite spec in Deneb

  1. 01

    List your fields

    Write the fields you will put in Deneb's Values well, one per line, exactly as they are named there. Add a type (temporal, quantitative, nominal, ordinal) when the name doesn't make it obvious.

  2. 02

    Describe the chart and generate

    Describe the chart and click Generate. In 15–60 seconds you get the spec, a rendered preview and import steps.

  3. 03

    Add Deneb and the fields

    In Power BI Desktop add the Deneb visual from Microsoft Marketplace (formerly AppSource) via Get more visuals and drag the same fields into its Values well.

  4. 04

    Create an empty Vega-Lite spec

    Open the visual's ⋯ menu → Edit, choose Vega-Lite and the empty template, then Create.

  5. 05

    Paste and apply

    Replace the whole specification with the generated JSON and apply it. Enable cross-filtering in Project setup if the result says the spec uses it.

Limits

  • Up to 30 fields and 200 sample rows; descriptions up to 2,000 characters.
  • Vega-Lite v5 only (no raw Vega). Specs up to 60,000 characters.
  • The preview is rendered at 480×300 in place of the visual's container size, with the sample rows — not your model.
  • Specs that would draw an extreme number of marks are stopped by a time and memory limit and count as a failure (refunded).
  • Up to 6 generations a minute and 60 an hour per account.

Pricing

Each generation costs 1 credit ($0.70–$1.00 depending on the pack). The credit is reserved when you click Generate and refunded automatically if the AI times out, refuses, or its output fails validation after one automatic repair. Credits are one-time packs, not a subscription, and are shared with the custom visual generator.

See credit packs

Questions

What is Deneb?

Deneb is a free, Microsoft-certified custom visual for Power BI that renders charts written in Vega or Vega-Lite, the declarative JSON grammars from the University of Washington. Because it is certified, it works in tenants that block uncertified visuals, and the spec lives inside the report.

How do I use a generated spec as a Deneb template?

Add the Deneb visual, put your fields in its Values well with the exact names you gave the generator, open Edit, create a new Vega-Lite specification from the empty template and replace its JSON with the generated spec. The page lists the steps with every result.

Is the spec actually tested?

Yes. The JSON is compiled with Vega-Lite and run in a headless Vega view on sample rows (yours, or rows synthesised from the field types), with all network access disabled. You see that render as the preview. If compiling or rendering fails, the AI gets one automatic repair with the exact error; if that fails too, the credit is refunded.

Does it support cross-filtering?

If you ask for click-to-filter, the spec styles marks with Deneb's __selected__ field (on, off or neutral). Deneb only provides that field after you enable 'Expose cross-filtering values for dataset rows' under Project setup → Cross-filtering in the Deneb editor, which is off by default; the result tells you when that's needed.

Why must field names match exactly?

Deneb passes your Values well to the spec as a dataset called "dataset", with one column per field named by its display name. A spec that says Sales where the well says Total Sales draws nothing. The generator only allows the names you list. Names that contain dots or square brackets (Avg. Price, Sales [EUR]) must be escaped with a backslash in Vega-Lite, and specs that leave them unescaped are rejected and repaired before you see them.

Does the AI see my data?

Only what you type into the form. If you paste sample rows, the first 5 rows are sent to the AI model (Anthropic's Claude) as examples, and all of them are used to compile and render the preview on our server. VizForge does not store them. For confidential data, leave the sample box empty: rows are then synthesised from the field types. The AI never connects to your Power BI model.

Vega or Vega-Lite?

The generator writes Vega-Lite v5, which Deneb supports alongside Vega. Vega-Lite covers bar, line, area, scatter, heatmap, layered and faceted charts with far shorter specs; switch to Vega only when you need custom signals or layouts Vega-Lite can't express.

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