Custom Themes: Brand Your SlideForge Output

Every slide SlideForge generates uses a theme — colors, fonts, and spacing that make the output look like your brand, not a generic template.8 built-in themes work out of the box. Custom themes let you match your company's exact brand identity. Three ways to create one: JSON, upload a .pptx, or let an agent extract it.

Built-in themes

Every request defaults to consulting_blue if no theme is specified. 8 built-in themes cover common styles:

Use any built-in theme by passing theme_id in your request:

curl -X POST https://api.slideforge.dev/v1/render \
  -H "Authorization: Bearer sf_live_YOUR_KEY" \
  -d '{"template": "kpi_dashboard", "brief": "Revenue $12.4M", "theme_id": "consulting_dark"}'

Method 1: Create from JSON

Define your brand colors programmatically. Colors are required; typography and spacing have sensible defaults.

curl -X POST https://api.slideforge.dev/v1/themes \
  -H "Authorization: Bearer sf_live_YOUR_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "name": "acme_brand",
    "colors": {
      "primary": "#2B5EA7",
      "secondary": "#1A3C6E",
      "accent": "#E87722",
      "background": "#FFFFFF",
      "text": "#1A1A2E",
      "light_text": "#FFFFFF"
    },
    "typography": {
      "font_family": "Calibri"
    }
  }'

# Returns: {"theme_id": "acme_brand", ...}

The theme is saved to your account and persists across sessions. Use it with theme_id: "acme_brand" in any generate, render, or deck request.

Color fields

• primary — main brand color (headers, key shapes)
• secondary — supporting color (sub-headers, secondary shapes)
• accent — highlight color (callouts, emphasis, trends)
• background — slide background
• text — body text color
• light_text — text on dark backgrounds

The engine auto-generates a tint ramp from your primary color (90%, 70%, 50%, 30% opacity) for gradients and subtle fills. WCAG contrast is computed automatically for text readability.

Method 2: Extract from a .pptx file

Already have a branded PowerPoint template? Upload it and SlideForge extracts the theme — colors, fonts, slide dimensions, and logo.

curl -X POST https://api.slideforge.dev/v1/themes/upload \
  -H "Authorization: Bearer sf_live_YOUR_KEY" \
  -F "file=@brand-template.pptx" \
  -F "name=acme_from_pptx"

# Returns: {"theme_id": "acme_from_pptx", "colors": {...}, "typography": {...}}

The extractor reads the slide master's color scheme, font theme, and dimensions. If the template has a logo in the header/footer zone, it's extracted and stored as an asset automatically.

Method 3: Via MCP (agent-assisted)

In Claude Desktop, use the upload_file tool with purpose: "theme":

// Agent conversation:
You: "Extract our brand theme from this PowerPoint template"
AI: *calls upload_file with purpose="theme"*
AI: "I extracted your theme: primary #2B5EA7, accent #E87722, font Calibri.
     Saved as theme_id 'acme_brand'. Want me to generate a slide with it?"

Adding a logo

Upload your company logo separately — it gets placed in the slide chrome (header area) automatically.

curl -X POST https://api.slideforge.dev/v1/assets/logo \
  -H "Authorization: Bearer sf_live_YOUR_KEY" \
  -F "file=@logo.png"

# Returns: {"logo_id": "a1b2c3d4", "blob_url": "..."}

PNG, JPG, SVG, GIF, or WebP — max 5 MB. The logo persists across sessions. Use it with your theme for fully branded slides.

Listing your themes

curl https://api.slideforge.dev/v1/themes \
  -H "Authorization: Bearer sf_live_YOUR_KEY"

# Returns: built-in themes + your custom themes with color swatches

Via MCP: list_themes returns all available themes.

Theme schema reference

Get the full JSON schema with field descriptions:

curl https://api.slideforge.dev/v1/themes/template \
  -H "Authorization: Bearer sf_live_YOUR_KEY"

This returns the complete schema with defaults — useful for programmatically building themes or validating input.

Tips

• Start with a built-in theme and customize from there — change just the colors to match your brand.
• Primary color matters most — it drives headers, key shapes, and the tint ramp. Secondary and accent are supporting.
• Test with a KPI dashboard — it uses all color slots, so you can see the full palette in one slide.
• Font availability — the API container has Calibri, Arial, Helvetica, and common fonts. If your brand font isn't available, the engine falls back gracefully.

Related guides

• How to write effective briefs — get better slides from every template and theme
• Add PowerPoint export to your SaaS — per-customer themes for white-label output
• Automate reports from Excel — combine themes with scheduled report generation
• SlideForge vs python-pptx — why an API beats managing theme code yourself

Get started

Browse themes in the console, or read the full API reference. Sign up for $3 free credit to try custom themes.