# Deploy ASP.NET Core to a Linux VPS with PostgreSQL

Deploy an ASP.NET Core app to your own Linux VPS: ox installs the .NET 10 SDK, runs dotnet publish, starts the DLL under systemd, and adds PostgreSQL.

To deploy ASP.NET Core to a Linux VPS with ox, add the repo as a project and deploy it, with no Dockerfile and no ox.toml. ox reads `src/Api/Api.csproj` and `src/Api/Program.cs`, runs `dotnet publish src/Api/Api.csproj -c Release -o out`, then starts `dotnet out/Api.dll` under systemd behind Caddy with HTTPS, and sets up postgres 18 for it. Run `ox check` in your repo to see the same plan before the first deploy.

**Plan verified, real-server test pending.** The plan below is what `ox check` prints for a minimal ASP.NET Core repo in ox's tests. A deploy on a real server is not recorded yet.

ox reads `src/Api/Api.csproj` and `src/Api/Program.cs`, builds the plan on the card, and starts `dotnet out/Api.dll` on your server. The cylinders are the services the repo asked for.

## What ox detects in a ASP.NET Core repo

This is the plan `ox check` prints for a minimal an ASP.NET Core app, with no ox.toml. Each row says where its value came from: a file in the repo, or ox's default.

| Field | Value | Source |
| --- | --- | --- |
| `app.start` | `ASPNETCORE_URLS=http://127.0.0.1:$PORT dotnet out/Api.dll` | `detected:src/Api/Api.csproj` |
| `app.health` | `/healthz` | `detected:src/Api/Program.cs` |
| `build.commands[0]` | `dotnet publish src/Api/Api.csproj -c Release -o out` | `detected:src/Api/Api.csproj` |
| `packages` | `dotnet-sdk-10.0` | `detected:src/Api/Api.csproj` |
| `services.postgres` | `postgres 18 (shared)` | `detected:src/Api/Api.csproj` |

`ox check` also prints these hints for it:

- `Npgsql reads a connection string, not DATABASE_URL: set ConnectionStrings__Default to Host=${postgres.host};Port=${postgres.port};Database=${postgres.database};Username=${postgres.user};Password=${postgres.password}`

## The ox.toml for ASP.NET Core

None is needed: the plan above comes from the repo alone. Write one to serve your own domain or to change what ox detected. This one passes `ox check` against the same repo: `[app]` keeps the detected start command and build. Once a repo has an ox.toml, ox adds no service itself, so list each one under `[services]`.

ox.toml, optional:

```toml
domains = ["www.example.com"]

[app]

[services]
postgres = {}
```

## Check and deploy ASP.NET Core

Add the repo as a project, then check and ship it from a terminal:

Check, deploy and read the logs:

```sh
ox check                                # in the repo: the plan above, offline
ox new <owner/repo> --server <server>  # add the repo as a project
ox deploy <project> --wait              # stream the deploy, exit with its result
ox logs <project> --follow             # the app's own logs
```

## Variables to set for ASP.NET Core

None before the first deploy: `ox check` asks for no variable. Add your own on the dashboard's Variables tab or with `ox vars set <project> KEY`.

ox provides these to the app itself: `PORT`, `HOST`, `OX_ENV`, `OX_PROJECT`, `OX_RELEASE`, `OX_DATA_DIR`, `PUBLIC_URL`, `PUBLIC_HOST` and `DATABASE_URL`.

## If the ASP.NET Core deploy fails

- `several ASP.NET Core projects (src/Api/Api.csproj, src/Admin/Admin.csproj); set [build] commands to dotnet publish <project> -c Release -o out and [app] start to the one to run`: Name the project to publish in `[build] commands` and the DLL to run in `[app] start`. [More](https://deploywithox.com/docs/config#build).
- `TCP connect to 127.0.0.1:8001 did not answer within 120s: dial tcp 127.0.0.1:8001: connect: connection refused`: The app started but never answered on the port ox gave it. Listen on `127.0.0.1` at `$PORT`; the lines above the message are the app's own output. [More](https://deploywithox.com/docs/troubleshooting#health-check-failed).
- `web of shop on main keeps crashing: systemd restarted it 5 times in the last 10 minutes. The Logs tab shows why.`: The release went live and then kept dying. Read the Logs tab for the error and deploy a fix, or roll back. [More](https://deploywithox.com/docs/troubleshooting#crash-loop).

Your visitors never see a failed deploy: the previous release keeps serving until the new one passes its health check.

## Next steps

- [Set variables and secrets](https://deploywithox.com/docs/operate/variables#set) on the dashboard or with `ox vars`.
- [The `[app]` keys](https://deploywithox.com/docs/config#app): start, health check, memory and the rest.
- [Service dashboards](https://deploywithox.com/docs/operate/services): your database's status, size, backups and data.
- [Add a custom domain](https://deploywithox.com/docs/operate/domains) with one A record; Caddy gets the HTTPS certificate.
- [Read the logs](https://deploywithox.com/docs/operate/logs) live, search them, or download them.
- [Set variables and secrets](https://deploywithox.com/docs/operate/variables) on the dashboard or with `ox vars`.

## ASP.NET Core FAQ

### Do I need a Dockerfile or an ox.toml to deploy ASP.NET Core to a Linux VPS?

No. ox does not use Docker, and `ox check` on a ASP.NET Core repo with no ox.toml prints `Ready to deploy.` Write an ox.toml only to change what ox detected.

### What does ox install on the server for ASP.NET Core?

Only what the plan names: the apt packages `dotnet-sdk-10.0`. Your app's own dependencies are installed by the build into the release folder, not system-wide.

### How does the app connect to PostgreSQL?

Npgsql reads a connection string, not `DATABASE_URL`. Set `ConnectionStrings__Default` from the service's values, as the hint above shows.

## Related guides

- [**Rust**Deploy a Rust web app from a Cargo workspace to your own VPS: ox installs stable Rust, runs cargo build --release --locked, and starts the binary.](https://deploywithox.com/docs/guides/rust)
- [**React with Vite**Deploy a React app built with Vite to your own VPS with no Dockerfile: ox runs the build from your lockfile and Caddy serves dist over HTTPS, no ox.toml.](https://deploywithox.com/docs/guides/react-vite)

Every stack ox deploys, and the ones it does not yet, is on the [Stacks page](https://deploywithox.com/docs/guides).

Last updated 2026-10-09. The page as HTML: https://deploywithox.com/docs/guides/aspnet-core