Custom Vision Training Client
Custom Vision Training Client
Custom Vision Training API programmatically trains image-classification / object-detection models — create projects, upload labeled images, trigger training, publish iterations.
Fully programmatic — script the entire training flow
No SLA on training time (typically minutes to tens of minutes)
Create a Custom Vision Training resource in Azure for endpoint + training key. POST /customvision/v3.4-preview/training/projects to create, upload images, then POST /train to trigger training.
Uptime · 30-day window
About this API
Custom Vision Training API is the programmatic counterpart of the visual training UI. Compared to the portal, the Training API's value is automation — e.g. a data pipeline that collects new labeled samples from production daily and auto-retrains and publishes a new version. The API covers project management, tag management, image+label upload, training trigger, iteration management, and publish operations. Supports classification (multi-label and single-label) and object detection (with bounding boxes). After training, inference goes through Prediction API.
What you can build
- 1Auto-retrain models in CI/CD when new labeled data arrives
- 2Bulk upload training data
- 3A/B test multiple model iterations
- 4Integrate training into ML pipelines
Strengths & limitations
Strengths
- Fully programmatic — script the entire training flow
- Multiple iterations per project for A/B comparison
- Supports transfer learning (fine-tune from a general model)
Limitations
- No SLA on training time (typically minutes to tens of minutes)
- For complex tasks, Azure Machine Learning is a better fit
Example request
curl https://microsoft.com/<endpoint>Getting started
Create a Custom Vision Training resource in Azure for endpoint + training key. POST /customvision/v3.4-preview/training/projects to create, upload images, then POST /train to trigger training.
FAQ
How do I use the model after training?+
Call publish iteration to push a specific iteration to the Prediction endpoint, then invoke via Prediction API.
How many iterations per project?+
Up to 20 iterations retained per project; you must delete older ones to add new ones.
Technical details
- Auth type
- unknown
- Pricing
- unknown
- Protocols
- REST
- SDKs
- python, javascript, csharp, java, go
- Response time
- 77 ms
- Last health check
- 5/12/2026, 7:37:52 AM
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