7 hours ago
Service is pinned to the Nixpacks builder via railway.json (no Config File path set, picked up by convention). If I remove the builder key, does the service fall back to the Builder value in service settings, or to the Railpack default? And can Nixpacks still be selected in the dashboard once no config file is setting it?
3 Replies
7 hours ago
Removing the builder key from your railway.json causes the deployment to fall back to the service settings value in the dashboard, per the documented config resolution priority (config in code > service settings). The only valid builder values today are RAILPACK (default) and DOCKERFILE, so Nixpacks is not selectable in the dashboard or config file. Also worth noting: Config as Code (railway.json) is deprecated with a hard cutoff of 2026-12-01 for existing services, and Infrastructure as Code (.railway/railway.ts) is the replacement.
Status changed to Awaiting User Response Railway • about 7 hours ago
Railway
Removing the `builder` key from your `railway.json` causes the deployment to fall back to the service settings value in the dashboard, per the documented [config resolution priority](https://docs.railway.com/config-as-code/reference#setting-environment-overrides) (config in code > service settings). The only valid builder values today are `RAILPACK` (default) and `DOCKERFILE`, so Nixpacks is not selectable in the dashboard or config file. Also worth noting: Config as Code (`railway.json`) is [deprecated](https://docs.railway.com/config-as-code) with a hard cutoff of 2026-12-01 for existing services, and [Infrastructure as Code](https://docs.railway.com/infrastructure-as-code) (`.railway/railway.ts`) is the replacement.
3 hours ago
Understood that Nixpacks can't be selected. Two specifics before I migrate: does nixpacks.toml stop being read entirely under Railpack, and is railpack.json's deploy.aptPackages the correct home for runtime system packages — specifically fonts-noto-cjk and the Chromium libs that puppeteer needs at request time?
Status changed to Awaiting Railway Response Railway • about 3 hours ago
3 hours ago
Railpack does not read nixpacks.toml at all; its configuration sources are railpack.json, environment variables, and Mise config files, so your existing nixpacks.toml will be silently ignored once you switch. Yes, deploy.aptPackages in railpack.json is the correct place for runtime system packages - use the "..." spread entry to keep Railpack's own defaults alongside yours, e.g. "aptPackages": ["...", "fonts-noto-cjk", "chromium"] (docs).
Status changed to Awaiting User Response Railway • about 3 hours ago