# Anthropic Messages API

**Canonical:** https://apis.io/apis/anthropic/anthropic-messages-api/  
**Provider:** Anthropic — https://apis.io/providers/anthropic/  
**Documentation:** https://docs.anthropic.com/en/api/messages

Anthropic Messages API is one of 24 APIs that [Anthropic](https://apis.io/providers/anthropic/) publishes on the [APIs.io](https://apis.io/) network, described by a machine-readable OpenAPI specification and an AsyncAPI event-driven specification. This API exposes 2 JSON Schema definitions. Tagged areas include Artificial Intelligence and Message. The published artifact set on APIs.io includes API documentation, an OpenAPI specification, an AsyncAPI specification, a JSON-LD context, and 2 JSON Schemas.

Send a structured list of input messages with text and/or image content, and the model will generate the next message in the conversation. The Messages API supports text, images, tool use, extended thinking, streaming, structured outputs, prompt caching, compaction, and the new advisor tool for pairing executor and higher-intelligence advisor models.

## Machine-readable artifacts (20)

- **Documentation** — https://docs.anthropic.com/en/api/messages
- **Documentation** — https://docs.anthropic.com/en/api/messages-streaming
- **OpenAPI** — https://raw.githubusercontent.com/api-evangelist/anthropic/refs/heads/main/openapi/anthropic-messages-api-openapi.yml
- **AsyncAPI** — https://raw.githubusercontent.com/api-evangelist/anthropic/refs/heads/main/asyncapi/anthropic-asyncapi.yml
- **JSONSchema** — https://raw.githubusercontent.com/api-evangelist/anthropic/refs/heads/main/json-schema/anthropic-message-schema.json
- **JSONSchema** — https://raw.githubusercontent.com/api-evangelist/anthropic/refs/heads/main/json-schema/anthropic-tool-use-schema.json
- **JSONLD** — https://raw.githubusercontent.com/api-evangelist/anthropic/refs/heads/main/json-ld/anthropic-context.jsonld
- **GraphQL** — https://raw.githubusercontent.com/api-evangelist/anthropic/refs/heads/main/graphql/anthropic-graphql.md
- **APIsJSON** — https://raw.githubusercontent.com/api-evangelist/anthropic/refs/heads/main/apis.yml
- **Arazzo** — https://raw.githubusercontent.com/api-evangelist/anthropic/refs/heads/main/arazzo/anthropic-batch-cancel-and-confirm-workflow.yml
- **Arazzo** — https://raw.githubusercontent.com/api-evangelist/anthropic/refs/heads/main/arazzo/anthropic-batch-create-poll-results-workflow.yml
- **Arazzo** — https://raw.githubusercontent.com/api-evangelist/anthropic/refs/heads/main/arazzo/anthropic-count-tokens-then-message-workflow.yml
- **Arazzo** — https://raw.githubusercontent.com/api-evangelist/anthropic/refs/heads/main/arazzo/anthropic-create-workspace-and-add-member-workflow.yml
- **Arazzo** — https://raw.githubusercontent.com/api-evangelist/anthropic/refs/heads/main/arazzo/anthropic-discover-model-and-message-workflow.yml
- **Arazzo** — https://raw.githubusercontent.com/api-evangelist/anthropic/refs/heads/main/arazzo/anthropic-invite-org-member-and-confirm-workflow.yml
- **Arazzo** — https://raw.githubusercontent.com/api-evangelist/anthropic/refs/heads/main/arazzo/anthropic-list-batches-and-fetch-latest-results-workflow.yml
- **Arazzo** — https://raw.githubusercontent.com/api-evangelist/anthropic/refs/heads/main/arazzo/anthropic-onboard-member-to-workspace-workflow.yml
- **Arazzo** — https://raw.githubusercontent.com/api-evangelist/anthropic/refs/heads/main/arazzo/anthropic-provision-and-promote-workspace-member-workflow.yml
- **Arazzo** — https://raw.githubusercontent.com/api-evangelist/anthropic/refs/heads/main/arazzo/anthropic-upload-list-and-cleanup-file-workflow.yml
- **Arazzo** — https://raw.githubusercontent.com/api-evangelist/anthropic/refs/heads/main/arazzo/anthropic-upload-verify-download-file-workflow.yml

## Other Anthropic APIs (12)

- [Anthropic Models API](https://apis.io/apis/anthropic/anthropic-models-api/)
- [Anthropic Message Batches API](https://apis.io/apis/anthropic/anthropic-message-batches-api/)
- [Anthropic Files API](https://apis.io/apis/anthropic/anthropic-files-api/)
- [Anthropic Token Counting API](https://apis.io/apis/anthropic/anthropic-token-counting-api/)
- [Anthropic Skills API](https://apis.io/apis/anthropic/anthropic-skills-api/)
- [Anthropic Claude Code Analytics API](https://apis.io/apis/anthropic/anthropic-claude-code-analytics-api/)
- [Anthropic Agents API](https://apis.io/apis/anthropic/anthropic-agents-api/)
- [Anthropic Api Keys API](https://apis.io/apis/anthropic/anthropic-api-keys-api/)
- [Anthropic Cost API](https://apis.io/apis/anthropic/anthropic-cost-api/)
- [Anthropic Environments API](https://apis.io/apis/anthropic/anthropic-environments-api/)
- [Anthropic Events API](https://apis.io/apis/anthropic/anthropic-events-api/)
- [Anthropic Organization API](https://apis.io/apis/anthropic/anthropic-organization-api/)

## Tags

Artificial Intelligence, Message

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Profiled by [API Evangelist](https://apievangelist.com) and published on [APIs.io](https://apis.io/apis/anthropic/anthropic-messages-api/). The API's provider profile, Kin Score and agent-readiness rating are at https://apis.io/providers/anthropic/.