Use the Prefect Web UI

Prefect's local web UI displays flow runs, individual tasks, timing, retries, logs, and failures.

Start the server

From the repository root, start the persistent local Prefect server:

uv run prefect server start

Leave that terminal running and open:

http://127.0.0.1:4200

Stop the server with Ctrl+C.

Prefect stores local history in ~/.prefect/prefect.db by default. Runs created by Prefect's automatic temporary server use the same database unless its home or database settings were overridden, so earlier local runs remain visible.

Connect a flow run

With the server running, launch a flow from another terminal:

PREFECT_API_URL=http://127.0.0.1:4200/api \
  uv run nba-fetch-season 2025-26 --max-workers 4

The flow and its game tasks appear in the UI while they execute.

The same connection applies to processing and compaction:

PREFECT_API_URL=http://127.0.0.1:4200/api \
  uv run nba-process-season 2025-26 --max-workers 4

PREFECT_API_URL=http://127.0.0.1:4200/api \
  uv run nba-compact-season 2025-26 --max-workers 4

Season compaction appears as one flow with one task for each table and season-type partition.

Save the connection

Store the local API URL in the active Prefect profile:

uv run prefect config set \
  PREFECT_API_URL=http://127.0.0.1:4200/api

After saving this setting, the local server must be running whenever a flow is launched. Inspect the active configuration with:

uv run prefect config view --show-sources

Restore automatic temporary-server behavior with:

uv run prefect config unset PREFECT_API_URL

See Prefect's official guides for running a local server and managing settings.