---

name: app-backends description: "Operate AutoTrain Advanced FastAPI app/API, spacerunner, backend selection, auth, jobs, and safe route checks." disable-model-invocation: true metadata: disco-role: operating parent-skill: autotrain-advanced license: Apache 2.0

AutoTrain app, API, and backends

Use this sub-skill for the local UI, training API, Space runner, backend keys, hosted backend auth, job/log inspection, and app/API task parameter routing.

Supported entry points

• autotrain app --help
• autotrain api --help
• autotrain spacerunner --help
• FastAPI app object: autotrain.app.app:app
• Training API object: autotrain.app.training_api:api
• Backend keys from autotrain.backends.base.AVAILABLE_HARDWARE
• App parameter helper: autotrain.app.params.get_task_params(task, param_type)

Safe route checks

Use the bundled script to probe importable app routes without starting uvicorn:

python skills/disco/autotrain-advanced/sub-skills/app-backends/scripts/check_app_api.py

Expected safe checks include:

• main app / redirecting toward /ui/;
• main app /api/version returning the package version;
• training API route registration for / and /health without issuing requests to that app, because its lifespan hook starts training.

Backend families

• Local: local, local-cli, local-ui
• Hugging Face Spaces: keys beginning with spaces-
• Hugging Face endpoints: keys beginning with ep-
• NVIDIA GPU Cloud: keys beginning with dgx-
• NVIDIA Cloud Functions: keys beginning with nvcf-

Use the root scripts/check_backends.py helper to print the available key list from the installed package.

Auth and environment signals

• autotrain app --share requires NGROK_AUTH_TOKEN.
• Hosted backends usually need a Hugging Face username/token and Hub-accessible artifacts.
• Training API startup logs environment-derived values such as AUTOTRAIN_USERNAME, PROJECT_NAME, TASK_ID, DATA_PATH, and MODEL.
• In hosted Spaces, SPACE_ID activates OAuth attachment for the main app.

References

• references/workflows.md — CLI service commands and app/API probes.
• references/backend-reference.md — backend key families and when to use them.
• references/troubleshooting.md — auth, route, job, ngrok, and hosted backend issues.