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Overview

The API server is started with zombied serve. It listens for HTTP requests on port 3000 and exposes Prometheus metrics on port 9091. The server handles authentication, spec validation, run lifecycle, workspace management, and webhook delivery.

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Network topology

The API runs on Fly.io inside a Docker container. It is not exposed on a public *.fly.dev address. Instead, a Cloudflare Tunnel connects the Fly.io instance to Cloudflare’s edge network.
  • HTTPS termination happens at the Cloudflare edge.
  • Internal traffic between Cloudflare Tunnel and the Fly.io container is plain HTTP.
  • All public traffic routes through api.usezombie.com on the Cloudflare edge.
Client --> Cloudflare Edge (HTTPS) --> Cloudflare Tunnel --> zombied serve (HTTP :3000)

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Deployment

The API is deployed as a Docker container on Fly.io. 
FROM debian:bookworm-slim
COPY zombied /usr/local/bin/zombied
EXPOSE 3000 9091
CMD ["zombied", "serve"]
Deploy with the Fly CLI: 
fly deploy --app zombied-api

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Ports

PortPurpose
3000HTTP API (default, configurable via PORT)
9091Prometheus metrics (configurable via METRICS_PORT)

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Health checks

The API exposes two health endpoints:
EndpointPurpose
GET /healthzLiveness probe — returns 200 if the process is running.
GET /readyzReadiness probe — returns 200 if PostgreSQL and Redis are reachable.

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Startup checks

On boot, zombied serve validates that all required environment variables are set and that it can connect to PostgreSQL and Redis. If any check fails, the process exits with a non-zero code and a diagnostic message naming the missing dependency. See Environment variables for the full list of API configuration.