Chart updates

Replace chart data in an existing presentation without regenerating the deck.

Chart updates replace the data inside a chart that was already generated (or uploaded), without regenerating the deck. The chart’s type, colours, legend, axis formatting, and position on the slide are preserved — only the categories, series values, and optional data rows change.

When to use chart updates vs. regeneration

Use chart updates when you want to refresh chart data in a deck that already exists — either one the API generated, or one a user edited manually in PowerPoint. Layout, formatting, and any manual edits to other slides are preserved.

Use full regeneration when the deck structure itself needs to change (different slides, different tables, different layouts).

Endpoint

PUT /api/v1/presentations/{presentation_id}/update-charts

The same endpoint handles two input modes:

• JSON body — reference a presentation already in storage by its ID
• Multipart form — upload a .pptx file and update charts in it in one request

JSON body (presentation already in storage)

PUT /api/v1/presentations/gen_abc123/update-charts
X-API-Key: your-api-key
Content-Type: application/json

{
  "updates": [
    {
      "slide_index": 6,
      "chart_index": 0,
      "chart_data": {
        "categories": ["Acme Corp", "TechFlow Inc", "DataSync Ltd", "CloudFirst", "Innovate Labs", "SecureNet", "GrowthMetrics", "Nexus Digital"],
        "series": [
          { "name": "Promoters (9-10)", "values": [50, 42, 18, 35, 48, 36, 15, 46] },
          { "name": "Passives (7-8)", "values": [30, 33, 30, 35, 32, 38, 28, 30] },
          { "name": "Detractors (0-6)", "values": [20, 25, 52, 30, 20, 26, 57, 24] }
        ],
        "data_rows": [
          ["n=", "156", "142", "89", "178", "201", "134", "67", "188"],
          ["NPS", "+30", "+17", "-34", "+5", "+28", "+10", "-42", "+22"]
        ],
        "data_table_header_column": true
      }
    }
  ]
}

The presentation_id path parameter accepts:

• gen_xxx — from slide generation, deck generation, or chart updates
• pres_xxx — older direct-return generation output, if present

Multipart form (upload a .pptx and update it)

Use this when a user has edited a deck manually in PowerPoint and you want to refresh chart data in the edited file.

PUT /api/v1/presentations/{presentation_id}/update-charts
X-API-Key: your-api-key
Content-Type: multipart/form-data

file: (binary .pptx)
updates: [{"slide_index": 6, "chart_index": 0, "chart_data": {...}}]

The updates field is a JSON string in the form body. When a file is uploaded, the path parameter is ignored — the response returns a new cupd_xxx ID for the updated file.

Response

{
  "presentation_id": "gen_abc123",
  "status": "completed",
  "slides_updated": 1,
  "file_size": 7450000,
  "download_url": "https://storage.example.com/download...",
  "download_url_expires_in": 3600,
  "created_at": "2024-01-15T10:45:00Z"
}

Update fields

Each entry in the updates array targets one chart:

Field	Type	Required	Description
slide_index	integer	yes	Zero-based slide index in the presentation
chart_index	integer	no (default 0)	Zero-based chart index on the slide
chart_data	object	yes	New chart data (see below)

chart_data fields

Field	Type	Required	Description
categories	string[]	yes	Category labels for the x-axis
series	object[]	yes	One object per series: { "name": "...", "values": [...] }
data_rows	string[][]	no	Rows rendered in the data table beneath the chart
data_table_header_column	bool	no (default true)	Whether the first value in each data_rows entry is a row header
data_table_format	object	no	Font overrides for the data table: font_name, font_size, bold, italic, color
chart_type	string	no	Override the chart type (e.g. "stacked_bar", "clustered_column")
title	string	no	Override the chart title text
title_format	object	no	Font overrides for the chart title
legend	object	no	Legend position and formatting
value_axis	object	no	Value axis formatting (min, max, labels)
category_axis	object	no	Category axis formatting
show_bar_labels	bool	no (default false)	Show value labels on bars
show_data_table	bool	no (default false)	Show the built-in PowerPoint data table
caption	string	no	Caption text below the chart

Only categories and series are required. Omitted fields are left unchanged from the existing chart.

Slide index after pagination

slide_index refers to the output presentation, not the original input array. If a table slide paginated into multiple pages during generation, subsequent slide indexes shift.

The generation response includes total_pages_generated and slide_results — use those to determine the correct output position for each chart.

Errors

Error	Status	Meaning
Slide index out of range	400	slide_index exceeds the number of slides
No chart found	400	No chart exists at that chart_index on the slide
Presentation not found	404	The presentation_id does not exist in storage

{
  "detail": "slide_index 7 out of range. Presentation has 7 slides (valid: 0-6)."
}