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What this is

The preview service generates image previews for projects, models, versions, and objects. The service returns PNG files. If a preview is not ready, the service returns a placeholder image.

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When to use it

Use the preview service when you need preview images in your application. Previews are generated in the background. They are cached after the first generation.

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When not to use it

Do not use the preview service for real-time rendering. Previews are static images. Do not use the preview service if you need interactive 3D views.

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The simplest working example

Get the preview for the latest version in a project: 
curl https://YOUR_SERVER_URL/preview/abc123
The endpoint returns a PNG image. Replace abc123 with your project ID.

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Notes for real projects

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Endpoints

All endpoints return PNG images. If a preview is missing, a placeholder image is returned. The URLs use legacy parameter names (streamId, branchName, commitId) for backward compatibility. These correspond to project ID, model name, and version ID in modern Speckle terminology.

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Get project preview

Returns the preview for the latest version in a project: 
GET /preview/{streamId}/{angle?}
  • streamId: Project ID (required)
  • angle: View angle such as iso, top, or front (optional)
curl https://YOUR_SERVER_URL/preview/abc123

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Get model preview

Returns the preview for the latest version in a specific model: 
GET /preview/{streamId}/branches/{branchName}/{angle?}
  • streamId: Project ID (required)
  • branchName: Model name (required)
  • angle: View angle (optional)
curl https://YOUR_SERVER_URL/preview/abc123/branches/main

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Get version preview

Returns the preview for a specific version: 
GET /preview/{streamId}/commits/{commitId}/{angle?}
  • streamId: Project ID (required)
  • commitId: Version ID (required)
  • angle: View angle (optional)
curl https://YOUR_SERVER_URL/preview/abc123/commits/def456

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Get object preview

Returns the preview for a specific object: 
GET /preview/{streamId}/objects/{objectId}/{angle?}
  • streamId: Project ID (required)
  • objectId: Object ID (required)
  • angle: View angle (optional)
curl https://YOUR_SERVER_URL/preview/abc123/objects/ghi789

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Authentication

Private projects require an authentication token: 
curl -H "Authorization: Bearer YOUR_TOKEN" https://YOUR_SERVER_URL/preview/abc123
Public projects work without a token.

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Self-hosted setup

The preview service must run separately. It requires:
  • Redis for the job queue
  • A database connection
  • The server URL for fetching objects
The service reads jobs from Redis. It generates previews with Puppeteer and caches the results. See the server deployment documentation for setup details.

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Speckle Cloud

Speckle Cloud (app.speckle.systems) has the preview service running. No setup is needed. The API is the same as self-hosted.