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Sail

Sail Messages API API

Anthropic-compatible Messages API endpoints.

Documentation Provider Profile APIs.io OpenAPI GitHub

Sail Messages API API is one of 5 APIs that Sail publishes on the APIs.io network, described by a machine-readable OpenAPI specification.

Tagged areas include Messages API. The published artifact set on APIs.io includes an OpenAPI specification.

This API exposes 2 operations across 2 paths, and defines 19 schemas. It is described by OpenAPI 3.1.0, at version 2026-02-18.

Requests are made against a single base URL, https://api.sailresearch.com/v1.

2 operations 2 paths 19 schemas 2 POST

Metadata

The identity and technical contract details declared by the specification.

Specification
OpenAPI 3.1.0
API Version
2026-02-18
Base URL
https://api.sailresearch.com/v1
Authentication
HTTP Bearer
Resource Areas
1

Authentication & Security 1

Sail Messages API API declares 1 security scheme for authenticating requests. It accepts HTTP bearer tokens (API Key) (BearerAuth). By default, every request must be authenticated.

Paths & Operations 2

Across 2 paths, the API surfaces 2 operations — 2 POST. Each is listed below with its method, path, parameters, and response codes.

Messages API 2

Anthropic-compatible Messages API endpoints.

POST
/messages
Create an Anthropic message
createMessage 1 param body → 200400401408500
POST
/messages/count_tokens
Count tokens for an Anthropic message
countMessageTokens body → 200400401429500

Schemas 19

The contract defines 19 schemas that model the data the API accepts and returns. The most detailed are CreateMessageRequest (13 properties), CountMessageTokensRequest (12 properties), AnthropicMessageResponse (8 properties), AnthropicToolUseBlock (5 properties). Each schema is shown below with its type and property counts.

RequestMetadata
object
Optional string metadata. completionwindow controls scheduling; completionwebhook/webhooktoken configure completion webhooks.
3 properties
AnthropicToolResultBlock
object
Result of a tool call, sent back in a user message.
5 properties 3 required
AnthropicToolUseBlock
object
Tool call emitted by the model. Return its outcome as a toolresult block in a follow-up user message.
5 properties 4 required
CountMessageTokensRequest
object
Same shape as a create-message request; maxtokens is optional and ignored for counting.
12 properties 2 required
AnthropicRedactedThinkingBlock
object
Redacted extended-thinking block. Accepted when replayed; the opaque encrypted reasoning is not used.
3 properties 2 required
CreateMessageRequest
object
13 properties 3 required
AnthropicImageBlock
object
Image content block. Image input is supported only on multimodal models; see the Models page.
3 properties 2 required
AnthropicUsage
object
2 properties 2 required
ErrorObject
object
4 properties 2 required
AnthropicTextBlock
object
3 properties 2 required
MessageTokenCountResponse
object
1 property 1 required
AnthropicMessageResponse
object
8 properties 8 required
ErrorResponse
object
1 property 1 required
AnthropicStreamEvent
object
One Server-Sent Event emitted when stream: true — the event's JSON data payload; the SSE event: line carries the same type.
1 property 1 required
AnthropicThinkingBlock
object
Extended-thinking reasoning block. When continuing a thinking conversation, replay it unchanged (including its signature).
4 properties 2 required
AnthropicOutputConfigFormat
object
4 properties 2 required
AnthropicMessageParam
object
2 properties 2 required
AnthropicOutputConfig
object
2 properties
AnthropicCacheControl
object
Prompt-cache hint (e.g. { "type": "ephemeral" }). Accepted on content blocks for Anthropic SDK compatibility but ignored — no cache read/write; see the Prompt…
1 property

Specification

The full machine-readable OpenAPI contract behind this narrative.

Source

sail-messages-api-api-openapi.yml Raw ↑

Other APIs Sail publishes across the network.

Sail Batches API API
AE Profile APIs.io
Sail Chat Completions API API
AE Profile APIs.io
Sail Models API API
AE Profile APIs.io
Sail Responses API API
AE Profile APIs.io
#Messages API
← Back to S APIs
API Details
ID
sail:sail-messages-api-api
Base URL
https://api.sailresearch.com/v1
Docs
https://docs.sailresearch.com/api-reference/chat-completions-api/create-a-chat-completion
Provider
Sail
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