Vespa.NET.Models 1.1.0

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Vespa.NET

The strongly-typed .NET SDK for Vespa.ai.

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// Define your model → deploy schema → search. That's it.
await client.Admin.DeploySchemaAsync<Product>();
await client.Documents.PutAsync(product.Id, product);
var results = await client.Search.NearestNeighborSearchAsync<Product>(embedding, p => p.Embedding, topK: 10);

Why Vespa.NET?

Features

Quick Start

1. Install

dotnet add package Vespa.NET

2. Define a model

[VespaDocument("product", Namespace = "myapp")]
public record Product
{
    [VespaId]
    public string Id { get; init; } = "";

    [VespaField(Name = "product_name", IndexingMode = IndexingMode.IndexAttributeSummary)]
    public string Name { get; init; } = "";

    [VespaField(Name = "price", IndexingMode = IndexingMode.AttributeSummary)]
    public decimal Price { get; init; }

    [VespaTensor("tensor<float>(x[128])", EnableIndex = true, DistanceMetric = DistanceMetric.Euclidean)]
    public VespaTensor Embedding { get; init; } = null!;
}

3. Deploy, index, search

var options = new VespaClientOptions
{
    Endpoint         = "http://localhost:8080",
    DefaultNamespace = "myapp"
};

using var httpClient = new HttpClient { BaseAddress = new Uri(options.Endpoint) };
using var client     = new VespaClient(httpClient, options);

// Deploy schema from C# attributes
await client.Admin.DeploySchemaAsync<Product>();

// Index a document
var product = new Product { Id = "p-1", Name = "Laptop", Price = 999.99m, Embedding = embeddings };
await client.Documents.PutAsync(product.Id, product);

// Search
var results = await client.Search.NearestNeighborSearchAsync<Product>(
    queryEmbedding, p => p.Embedding, topK: 10);

Tip: With [VespaDocument] on your model, documentType and namespace are inferred automatically in all operations. No strings needed.

Model-Aware API

When your model has [VespaDocument], all operations infer types automatically. [VespaField(Name)] drives both schema generation and JSON serialization.

// CRUD — no documentType needed
await client.Documents.PutAsync(product.Id, product);
var doc = await client.Documents.GetAsync<Product>(product.Id);
await client.Documents.DeleteAsync<Product>(product.Id);

// Field-level update with typed lambda builder
await client.Documents.UpdateFieldsAsync<Product>(product.Id, ops => ops
    .Field(p => p.Name, FieldOp.Assign("New Name"))
    .Field(p => p.Price, FieldOp.Multiply(0.9)));

// Nearest-neighbor — field name resolved via lambda
var results = await client.Search.NearestNeighborSearchAsync<Product>(
    queryEmbedding, p => p.Embedding, topK: 10);

// Visit
await foreach (var d in client.Documents.VisitAsync<Product>(selection: "product.price > 100"))
    Process(d.Fields);

// Selection-based bulk ops — typed builder, auto-loops on Vespa's continuation token
var resp = await client.Documents.UpdateBySelectionAsync<Product>(
    "product.category == \"legacy\"",
    ops => ops.Field(p => p.Status, FieldOp.Assign("archived")),
    cluster: "content");
// resp.DocumentCount is the total across all chunks

// Cross-cluster copy
await client.Documents.CopyBySelectionAsync(
    "product.tier == \"cold\"", "product",
    cluster: "hot", destinationCluster: "cold");

Note: ID normalisation: pass either "p-1" or "id:myapp:product::p-1" — the client strips the prefix automatically.

YQL Builder

using Vespa.Query;

var yql = YqlBuilder<Product>
    .Select(p => p.Name, p => p.Price)
    .Where(w => w.Field(p => p.Price).GreaterThan(10)
                 .And(sub => sub.Field(p => p.Name).Contains("laptop")))
    .OrderBy(p => p.Price, descending: true)
    .Limit(20)
    .Build();

Fluent request builder captures YQL + ranking in one chain:

var request = YqlBuilder<Product>
    .Select()
    .Where(w => w.HybridSearch(p => p.Embedding, "q", "userQuery", targetHits: 100))
    .Limit(20)
    .ToSearchRequest()
    .WithRankProfile("hybrid_twophase")
    .WithQueryTensor("q", "embed(e5small, @userQuery)")
    .WithUserInput("userQuery", searchText);

Full predicate reference, boolean composition, and validation rules in docs/yql-builder.md

Grouping & Aggregation

var request = new VespaSearchRequest
{
    Yql = YqlBuilder<Product>
        .Select()
        .GroupBy(
            GroupingBuilder.All()
                .Group("category")
                .Max(10)
                .OrderByDescending(GroupingAgg.Count())
                .Each(e => e.Output(GroupingAgg.Count(), GroupingAgg.Avg("price"))))
        .Build(),
    Hits = 0
};

var result = await client.Search.GroupByAsync<Product>(request);

Nested grouping, buckets, having, pagination, and full aggregation reference in docs/grouping.md

Bulk Feed

// Streaming pipeline with backpressure
var result = await client.Feed.FeedAsync(
    ReadFromDatabase(),             // IAsyncEnumerable<FeedDocument<Product>>
    documentType: "product",
    maxConcurrency: 64,             // parallel HTTP/2 streams
    boundedCapacity: 256,           // backpressure buffer
    onProgress: p => Console.Write($"\r{p.SuccessCount} docs..."));

Per-document conditions, BulkPut/Update/Delete, and FeedResult details in docs/feed.md

Multi-Tenant Dynamic Fields

For platforms where tenants define custom fields at runtime, [VespaExtraFields] provides a catch-all bag — similar to MongoDB's [BsonExtraElements]:

public record ProductFields
{
    // App-owned fields — strongly typed, used for ranking
    [VespaField(IndexingMode = IndexingMode.AttributeSummary)]
    public double Popularity { get; init; }

    // Tenant-defined fields — captured dynamically
    [VespaExtraFields]
    public Dictionary<string, JsonElement>? TenantFields { get; init; }
}

• Unmapped JSON fields are captured in the dictionary during deserialization
• Serialized flat alongside declared properties (not nested)
• Round-trip safe: deserialize then serialize preserves everything
• Schema builder ignores [VespaExtraFields] properties

Admin API

// Deploy from C# attributes
await client.Admin.DeploySchemaAsync<Product>();

// Multi-tenant: override tenant per-call
await client.Admin.DeploySchemaAsync<Product>(tenant: "acme");

// Deploy raw ZIP
await client.Admin.DeployAsync(zipStream);

// Cluster status
var status = await client.Admin.GetApplicationStatusAsync();
var ready   = await client.IsReadyAsync();
var version = await client.GetVersionAsync();
var metrics = await client.GetMetricsAsync();

Note: ApiKey, DefaultRequestHeaders, compression, timeout, and mTLS settings are applied to both the data-plane client and the admin/config-server client.

Tip: Health/state helpers such as HealthCheckAsync, IsReadyAsync, GetMetricsAsync, GetVersionAsync, and GetHistogramsAsync are best-effort on ordinary failures, but they still propagate OperationCanceledException when the request is cancelled.

Schema attributes, [VespaExtraFields], ApplicationPackageOptions, and CustomServicesXml in docs/schema.md

Configuration & Ops

<details> <summary><strong>DI Integration</strong></summary>

builder.Services.AddVespaClient(new VespaClientOptions
{
    Endpoint         = "http://localhost:8080",
    DefaultNamespace = "myapp",
    EnableRetry      = true
});

// Named client (multi-cluster)
builder.Services.AddVespaClient("analytics", new VespaClientOptions
{
    Endpoint = "http://analytics-vespa:8080"
});

// Inject
public class ProductService(IVespaClient vespa)
{
    public Task<VespaDocument<Product>?> Get(string id)
        => vespa.Documents.GetAsync<Product>(id);
}

</details>

<details> <summary><strong>Vespa Cloud (mTLS)</strong></summary>

var options = new VespaClientOptions
{
    Endpoint        = "https://myapp.vespa-cloud.com",
    CertificatePath = "/path/to/cert.pem",
    ClientKeyPath   = "/path/to/key.pem",
    // or: ClientCertificate = myCert,
    // or: ApiKey = "bearer-token"
};

</details>

<details> <summary><strong>Observability (OpenTelemetry)</strong></summary>

builder.Services.AddOpenTelemetry()
    .WithTracing(b => b.AddSource("Vespa.NET"))
    .WithMetrics(m => m.AddMeter("Vespa.NET"));

Spans: vespa.search, vespa.document.*, vespa.feed.pipeline, etc. Metrics: vespa.client.requests, vespa.client.request_duration, vespa.client.documents_written, etc.

</details>

<details> <summary><strong>Health Checks</strong></summary>

builder.Services.AddHealthChecks().AddVespa();

</details>

<details> <summary><strong>Testcontainers</strong></summary>

await using var vespa = new VespaContainer();
await vespa.StartAsync();
var (client, http) = vespa.CreateClientWithHttp("test");

Set VESPA_INTEGRATION_TESTS=1 to enable in CI.

</details>

Full configuration reference, exceptions, metrics table, and more in docs/configuration.md

Documentation

Running the Sample App

docker run --detach --name vespa --publish 8080:8080 --publish 19071:19071 vespaengine/vespa
dotnet run --project samples/Vespa.NET.Samples

Dependencies

Resources

• Vespa.ai Documentation
• YQL Reference
• Document API Reference

License

MIT License — see LICENSE for details.