---
title: "ANTHROPIC-COMPATIBLE /v1/messages — Claude Haiku 4.5 through the exact Anthropic API dialect"
method: POST
path: "/v1/messages"
tags: ["Inference"]
---

# ANTHROPIC-COMPATIBLE /v1/messages — Claude Haiku 4.5 through the exact Anthropic API dialect

`POST /v1/messages`

## Request

- Base URL: `https://api.webbersites.com`
- URL: `https://api.webbersites.com/v1/messages`
- Auth: API key in header `X-PAYMENT`

ANTHROPIC-COMPATIBLE /v1/messages — Claude Haiku 4.5 through the exact Anthropic API dialect: same request/response shape, no Anthropic account, the x402 payment IS the auth. Point an Anthropic SDK's base_url at https://api.webbersites.com and pay per call. Caps: 16,000 input chars, 1,024 output tokens (max_tokens clamped), text-only, no streaming.

Price: $0.01 per call, paid in USDC via the x402 protocol (see the x402 security scheme).

## Request body

- object
  - `model` string: claude-haiku-4-5 (the only model on this route)
  - `max_tokens` number: output cap, clamped to 1,024
  - `messages` unknown[], required: Anthropic-style messages: [{role, content}], text content only, 16,000 chars total
    - unknown
  - `system` string: optional system prompt (counts toward the input cap)

## Response `200`

Success

- object
  - `content` unknown[]: Anthropic-shape content blocks; the answer is content[0].text
    - unknown
  - `stop_reason` string
  - `usage` object

## Other responses

- `402`: Payment required — the response body lists accepted payment methods (amount, asset, network, pay-to address). Retry the request with a signed X-PAYMENT header.

---

[API](https://skmtc.dev/webbersites/apis/webbersites-x402-data-api.md) · [All operations](https://skmtc.dev/webbersites/apis/webbersites-x402-data-api/llms.txt) · [OpenAPI document](https://skmtc.dev/webbersites/apis/webbersites-x402-data-api/revisions/c14a76c67a94?raw)