After my last deployment, Railway started using Railpack instead of my configured Dockerfile, causing builds to fail.

Issue:

- My railway.json explicitly sets "builder": "DOCKERFILE"

- Previous deployments (until ~March 12, 2026) correctly used Dockerfile

- Current deployments ignore this and use Railpack 0.18.0

- Railpack fails because it detects the root package.json (which lacks a "start" script) instead of using the Dockerfile

Error message:

Region: europe-west4]

INFO No package manager inferred, using npm default

╭─────────────────╮

│ Railpack 0.18.0 │

╰─────────────────╯

No start command was found

Previous successful build log showed:

=========================

Using Detected Dockerfile

=========================

Environment:

- Region: europe-west4

- Metal Build Environment: Enabled

- railway.json present with builder: "DOCKERFILE"

- No changes to railway.json, Dockerfile, or package.json files in recent commits

What I've tried:

- Verified railway.json configuration is correct

- Confirmed Dockerfile exists and is valid (worked in previous deployments)

- No relevant code changes that would affect build detection

Suspected cause:

Possible regression with Metal build environment or recent Railway platform updates ignoring railway.json configuration.