FastAPI Scaling Analysis

Ranex provides a static FastAPI scaling analysis intended to surface patterns that commonly cause performance or scalability issues.

What it is (and is not)

• It is: static analysis of your local codebase.
• It is not: runtime profiling, load testing, APM, or production monitoring.

Configuration

FastAPI scaling analysis can be configured per project using:

• .ranex/fastapi_scaling.yaml

If this file does not exist, Ranex uses built-in defaults.

Run policy inspection

ranex atlas fastapi-scaling-policy --json

Use this to confirm what rules are active for the current project.

Run a scaling report

ranex atlas fastapi-scaling-report --json

The report typically includes:

• Summary statistics (endpoint counts, etc.)
• A list of violations, each with:
  • severity
  • message
  • file_path
  • qualified_name (when available)
  • suggestion (when available)

Router topology

ranex atlas fastapi-router-topology --json

This helps you understand how routes are split across routers vs direct app routes.

Truth capsule

A truth capsule is a structured JSON bundle meant for tooling and AI assistants to reason about a specific endpoint/handler.

ranex atlas fastapi-truth-capsule --json [filters...]

Common filters:

• --method
• --path
• --operation-id
• --handler-qualified-name

Recommended workflow

1. Run ranex atlas scan first.
2. Run a report in --json mode.
3. Fix issues and re-run the report.
4. Treat findings as guidance; validate improvements with real load testing.