SwarmGen + ChatGPT

Let your GPT generate branded images for users

Custom GPTs can call external APIs via GPT Actions. By adding SwarmGen as an action, your GPT can generate a personalised, branded image at any point in a conversation — triggered by user input, structured data extraction, or AI-driven logic. Combined with OpenAI's function calling, this makes it straightforward to build AI workflows that output real, rendered images.

How to set it up

1
Design the template
Create a SwarmGen template with merge fields that the GPT will populate — for example {{headline}}, {{sub_text}}, {{background_color}}.
2
Define a GPT Action (OpenAPI spec)
In your custom GPT configuration, add a new Action and paste in an OpenAPI schema that describes the SwarmGen render endpoint, including the required request body shape.
3
Set the authentication
In the GPT Action settings, set authentication to API Key (Bearer) and add your SwarmGen API key (starts with sgk_). ChatGPT will include it as an Authorization: Bearer header on every request.
4
Prompt the GPT to call the action
Write a system prompt that instructs the GPT when to generate images. The GPT extracts merge field values from the conversation and calls the SwarmGen action automatically.

Code example

GPT Action — OpenAPI schema (excerpt)yaml

openapi: 3.1.0
info:
  title: SwarmGen Render API
  version: 1.0.0
paths:
  /api/templates/{templateId}/render:
    post:
      operationId: renderTemplate
      summary: Render an image from a template and return a URL
      parameters:
        - name: templateId
          in: path
          required: true
          schema:
            type: string
          description: The SwarmGen template UUID
      requestBody:
        required: true
        content:
          application/json:
            schema:
              type: object
              required: [data]
              properties:
                data:
                  type: object
                  description: Merge field values to inject into the template
                returnUrl:
                  type: boolean
                  description: Return a signed URL instead of binary — set to true
      responses:
        '200':
          description: Render complete
          content:
            application/json:
              schema:
                type: object
                properties:
                  url:
                    type: string
                    description: Signed image URL, valid for 5 days
                  jobId:
                    type: string
                  format:
                    type: string
                  expiresAt:
                    type: string
                    format: date-time

Bespoke integrations are not supported by our team. The sample code here is for guidance and you will need technical knowledge or a developer to implement it. We plan to release dedicated plugins for key tools as demand grows.