VastAI.NET

VastAI.NET is a typed .NET client for the Vast.ai REST API.

Install

dotnet add package VastAI.NET

Configure

{
  "VastAI": {
    "ApiKey": "<vast-api-key>",
    "ApiBaseUri": "https://console.vast.ai/"
  }
}

The API key is required for live calls. Keep it in user secrets, environment variables, or host-specific secret storage.

Use With DI

using VastAI.NET;

builder.Services.AddVastAI(builder.Configuration);

var client = provider.GetRequiredService<IVastApiClient>();
var instances = await client.GetInstancesAsync();

Use With Runtime Values

Use this path when the API key is entered after startup, such as in a browser app or interactive CLI:

using VastAI.NET;

var client = VastApiClient.Create(apiKeyFromUserInput);
var instances = await client.GetInstancesAsync();

Hosts that already own an HttpClient can pass it:

var client = VastApiClient.Create(apiKeyFromUserInput, httpClient: httpClient);

API Usage

SearchOffersAsync

Use this to find rentable offers before creating an instance. Filters use Vast field names and comparison operators.

using VastAI.NET.Models;

var search = new VastSearchOffersRequest
{
  Limit = 5,
  Order = "dph_total"
};
search.Filters["rentable"] = new VastSearchFilter { EqualTo = true };
search.Filters["verified"] = new VastSearchFilter { EqualTo = true };
search.Filters["gpu_name"] = new VastSearchFilter { In = ["RTX_3060", "RTX_4090"] };
search.Filters["dph_total"] = new VastSearchFilter { LessThanOrEqualTo = 0.20 };
search.Filters["inet_up_cost"] = new VastSearchFilter { LessThanOrEqualTo = 1.0 / 1024.0 };
search.Filters["inet_down_cost"] = new VastSearchFilter { LessThanOrEqualTo = 1.0 / 1024.0 };

var offers = await client.SearchOffersAsync(search);

Order accepts compact Vast-style sort expressions: dph_total sorts ascending, dlperf_usd- sorts descending.

GetInstancesAsync

Use this for safety checks before renting and for account-level monitoring.

var instances = await client.GetInstancesAsync();
var active = instances.Where(instance => instance.IsActive).ToList();

VastInstance includes normalized status, label, GPU name, hourly price, estimated age, estimated cost, SSH target fields, public IP, exposed port mappings, and extra_env values when Vast returns them.

Use extra_env and exposed ports when reconnecting to software that was started by a Vast onstart command:

if (instance.TryGetExtraEnvironmentValue("VAST_LFS_TOKEN", out var workerToken) &&
    instance.TryGetPublicUriForContainerPort(8088, out var workerUri))
{
  Console.WriteLine(workerUri);
}

The full raw Vast instance object is also available for newly introduced Vast fields that do not yet have first-class properties:

if (instance.Raw.TryGetProperty("future_vast_field", out var value))
{
  Console.WriteLine(value?.ToJsonString());
}

GetInstanceAsync

Use this after create, while waiting for boot, or when refreshing one known instance.

var instance = await client.GetInstanceAsync(instanceId);

if (instance.HasSshTarget)
{
  Console.WriteLine($"{instance.SshUser}@{instance.SshHost}:{instance.SshPort}");
}

The parser handles Vast responses where instances is either an array or a single object.

CreateInstanceAsync

Use this only after selecting an offer and passing your own safety gates. This is a paid operation.

var create = new VastCreateInstanceRequest
{
  DiskGb = 20,
  Label = "lfs-smoke-test",
  Image = "vastai/base-image:@vastai-automatic-tag",
  RuntimeType = "ssh",
  CancelUnavailable = true,
  OnStart = "echo started"
};
create.Environment["-p 8080:8080"] = "1";
create.Environment["DATA_DIRECTORY"] = "/workspace/";

var result = await client.CreateInstanceAsync(offer.Id, create);
Console.WriteLine(result.InstanceId);

Vast REST requires Environment as a JSON object. Port mappings use keys such as -p 8080:8080 with value 1; environment variables use normal key/value pairs.

DestroyInstanceAsync

Use this to stop billing for an instance. Always call it from a finally block in tests or automation that rented an instance.

try
{
  var result = await client.CreateInstanceAsync(offer.Id, create);
  instanceId = result.InstanceId;
}
finally
{
  if (!string.IsNullOrWhiteSpace(instanceId))
    await client.DestroyInstanceAsync(instanceId);
}

The client uses bearer-token auth and the official Vast REST endpoints under https://console.vast.ai/.

Live Tests

Live tests are xUnit v3 explicit tests. They do not run during the normal suite.

dotnet user-secrets set "VastAI:ApiKey" "<vast-api-key>" --project .\tests\VastAI.NET.Tests\VastAI.NET.Tests.csproj
dotnet test .\tests\VastAI.NET.Tests\VastAI.NET.Tests.csproj --filter LiveVastApiTests -- xUnit.Explicit=on

CreateGetInstanceDestroyAsync_WithCheapLiveOffer_RentsAndDestroysInstance is paid. It rents one offer capped at $0.20/hr, destroys it in a finally block, and fails if active instances already exist.