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;

let credential = DeveloperToolsCredential::new(None)?;
let client = CosmosClient::new(
    "https://<account>.documents.azure.com:443/",
    credential.clone(),
    None,
)?;

Client Hierarchy

Client	Purpose	Get From
`CosmosClient`	Account-level operations	Direct instantiation
`DatabaseClient`	Database operations	`client.database_client()`
`ContainerClient`	Container/item operations	`database.container_client()`

Core Workflow

Get Database and Container Clients

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

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?;

Patch Item

use azure_data_cosmos::models::PatchDocument;

let patch = PatchDocument::default()
    .with_add("/newField", "newValue")?
    .with_remove("/oldField")?;

container.patch_item("partition1", "1", patch, 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

Always specify partition key — required for point reads and writes
Use into_model()? — to deserialize responses into your types
Derive Serialize and Deserialize — for all document types
Use Entra ID auth — prefer DeveloperToolsCredential over key auth
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

When to Use

This skill is applicable to execute the workflow or actions described in the overview.

Limitations

Use this skill only when the task clearly matches the scope described above.
Do not treat the output as a substitute for environment-specific validation, testing, or expert review.
Stop and ask for clarification if required inputs, permissions, safety boundaries, or success criteria are missing.

azure-cosmos-rust

Documentation