Stop AI from silently breaking your
FastAPI API
Ranex adds fail-closed guardrails for AI-written changes: workflow gates, drift checks, security scanning, and test integrity validation—so agents iterate until it's PASS.
For Python & FastAPI projects
Truth capsule for one endpoint
A truth capsule is a structured JSON bundle meant for tooling and AI assistants to reason about a specific FastAPI endpoint/handler.
Learn moreTruth capsule
Structured endpoint bundle (static)
Atlas architecture
Local-first flow from AI tools to project files
Router topology
Understand how routes are split across routers vs direct app routes.
FastAPI scaling report
Static analysis intended to surface patterns that commonly cause performance or scalability issues.
Dependency & import guardrails
The Dependency Firewall validates imports against an explicit policy to protect you from risky patterns, unknown dependencies, and typosquatting.
Learn morePolicy modes
Use strict to block unknown/not-allowed imports, audit_only for reporting, or disabled to turn off firewall decisions.
Fail-closed import checks
Check one import, check many imports, or analyze a file. Exit code 2 indicates blocked, unknown, or typosquat.
CLI & MCP integration
Use Ranex via the CLI, Python API, or from MCP-compatible assistants through a local MCP server (ranex-mcp-server) that communicates over stdio.
CLI first
Scan, query, and validate with --json for tooling
MCP server (optional)
ranex-mcp-server over stdio with RANEX_PROJECT_ROOT
Policy-as-code
Keep .ranex/firewall.yaml in version control
Preserve FastAPI API truth before you merge
Ranex is local-first: Atlas builds a project index and emits verifiable spans; FastAPI tooling generates truth capsules for a specific endpoint/handler; the Dependency Firewall validates imports against an explicit policy.
Learn moreMCP server (optional)
Use Ranex from MCP-compatible assistants via a local stdio server.
Span-first code truth
Use Atlas span tools to return exact (file, start_line, end_line) excerpts.
Dependency Firewall
Validate imports against an explicit policy to block risky patterns, unknown dependencies, and typosquatting.
Frequently Asked Questions
Everything you need to know about Ranex.
Still have questions? Contact our team
Ready to lock your FastAPI API?
Validate AI-generated changes with workflow gates, drift detection, and security scans— locally, with machine-readable failures your agent can fix.