Azure Cosmos DB SDK for Rust

Client library for Azure Cosmos DB NoSQL API — globally distributed, multi-model database.

Installation

cargo add azure_data_cosmos azure_identity

Environment Variables

COSMOS_ENDPOINT=https://<account>.documents.azure.com:443/
COSMOS_DATABASE=mydb
COSMOS_CONTAINER=mycontainer

Authentication

use azure_identity::DeveloperToolsCredential;
use azure_data_cosmos::{
    CosmosClient, CosmosAccountReference, CosmosAccountEndpoint, RoutingStrategy,
};

let credential: std::sync::Arc<dyn azure_core::credentials::TokenCredential> =
    DeveloperToolsCredential::new(None)?;
let endpoint: CosmosAccountEndpoint = "https://<account>.documents.azure.com:443/"
    .parse()?;
let account = CosmosAccountReference::with_credential(endpoint, credential);
let client = CosmosClient::builder()
    .build(account, RoutingStrategy::ProximityTo("East US".into()))
    .await?;

Client Hierarchy

Client	Purpose	Get From
CosmosClient	Account-level operations	CosmosClient::builder().build()
DatabaseClient	Database operations	client.database_client()
ContainerClient	Container/item operations	database.container_client().await?

Core Workflow

Get Database and Container Clients

let database = client.database_client("myDatabase");
let container = database.container_client("myContainer").await?;

Create Item

use serde::{Serialize, Deserialize};

#[derive(Serialize, Deserialize)]
struct Item {
    pub id: String,
    pub partition_key: String,
    pub value: String,
}

let item = Item {
    id: "1".into(),
    partition_key: "partition1".into(),
    value: "hello".into(),
};

container.create_item("partition1", item, None).await?;

Read Item

let response = container.read_item("partition1", "1", None).await?;
let item: Item = response.into_model()?;

Replace Item

let mut item: Item = container.read_item("partition1", "1", None).await?.into_model()?;
item.value = "updated".into();

container.replace_item("partition1", "1", item, None).await?;

Delete Item

container.delete_item("partition1", "1", None).await?;

Key Auth (Optional)

Enable key-based authentication with feature flag:

cargo add azure_data_cosmos --features key_auth

Best Practices

1. Always specify partition key — required for point reads and writes
2. Use into_model()? — to deserialize responses into your types
3. Derive Serialize and Deserialize — for all document types
4. Use Entra ID auth — prefer DeveloperToolsCredential over key auth
5. Reuse client instances — clients are thread-safe and reusable

Reference Links

Resource	Link
API Reference	https://docs.rs/azure_data_cosmos
Source Code	https://github.com/Azure/azure-sdk-for-rust/tree/main/sdk/cosmos/azure_data_cosmos
crates.io	https://crates.io/crates/azure_data_cosmos