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Clean API Routing with Firebase Hosting and Cloud Run

· 2 min read
Thorsten Fey
Thorsten Fey
IT-Support Specialist

This post documents a production-ready routing pattern for Firebase Hosting that avoids redirects, preserves clean URLs, and keeps API tooling intact.

It originated from a LinkedIn discussion after repeatedly seeing /api/** traffic handled via 302 redirects — a workaround that breaks DX, auth flows, and OpenAPI tooling at scale.

The setup uses Firebase Hosting strictly as a router and delegates API traffic to a minimal Nginx proxy running on Cloud Run.

graph TB
    A[Browser] -->|Request| B[Firebase Hosting]
    B -->|/docs| C[Static Content - Docusaurus]
    B -->|/api/**| D[Cloud Run - Nginx Proxy]
    D -->|upstream| E["/api/portal"]
    D -->|upstream| F["/api/leetcode"]
    
    style A fill:#e1f5ff
    style B fill:#fff4e6
    style C fill:#e8f5e9
    style D fill:#fce4ec
    style E fill:#f3e5f5
    style F fill:#f3e5f5

Firebase Hosting → Cloud Run API routing diagram

Why this pattern​

Firebase Hosting cannot proxy arbitrary external URLs while keeping the same origin.

Redirects solve this superficially, but introduce new problems:

  • broken API tooling
  • leaking infrastructure details
  • SPA router interference
  • brittle frontend workarounds

This pattern solves routing at the infrastructure layer instead.

Discussion​

This pattern sparked a broader discussion on LinkedIn around API routing in serverless setups.

👉 Join the discussion on LinkedIn