API referenceUsing the API
API overview
Understand the Claude API's available endpoints, authentication headers, client SDKs, pagination, rate limits, and cloud platform access options.
The Claude API is a RESTful API at https://api.anthropic.com that provides programmatic access to Claude models and Claude Managed Agents.
Prerequisites
To use the Claude API, you'll need:
- A Claude Console account
- An API key, or a configured Workload Identity Federation rule
For step-by-step setup instructions, see Get started.
Available APIs
The Claude API includes the following APIs:
- Messages API: Send messages to Claude for conversational interactions (
POST /v1/messages) - Message Batches API: Process large volumes of Messages requests asynchronously with 50% cost reduction (
POST /v1/messages/batches) - Token Counting API: Count tokens in a message before sending to manage costs and rate limits (
POST /v1/messages/count_tokens) - Models API: List available Claude models and their details (
GET /v1/models) - Files API: Upload and manage files for use across multiple API calls (
POST /v1/files,GET /v1/files) - Skills API: Create and manage custom agent skills (
POST /v1/skills,GET /v1/skills)
The following APIs are in beta:
- Agents API: Define reusable, versioned agent configurations for Claude Managed Agents (
POST /v1/agents,GET /v1/agents) - Sessions API: Run stateful agent sessions in managed cloud sandboxes (
POST /v1/sessions,GET /v1/sessions/{id}/events/stream) - Environments API: Configure sandbox templates for agent sessions (
POST /v1/environments,GET /v1/environments)