# api.webbersites.com Anthropic-Compatible Claude Haiku 4.5 Messages

> api.webbersites.com Anthropic-Compatible Claude Haiku 4.5 Messages is a paid API for AI agents from api.webbersites.com, paid per call via x402, $0.01/call, status healthy (last checked 2026-09-14, last successful call 2026-09-12).

Runs Claude Haiku 4.5 inference via the exact Anthropic /v1/messages API dialect, authenticated by x402 micropayment instead of an Anthropic API key

## Facts

- Endpoint: POST https://api.webbersites.com/v1/messages
- Price: $0.01/call
- Payment: x402
- Status: healthy
- Last checked: 2026-09-14
- Last successful call: 2026-09-12
- Success rate: 99% of calls made through Zero
- Rating: 4.3 / 5 from 1 review
- Activations on Zero: 76
- Tags: x402
- Canonical page: https://www.zero.xyz/c/api-webbersites-com-anthropic-compatible-claude-haiku-4-5-messages-88fd97bc
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_eG8sResSqDNuFNuiFYJ1g

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability api-webbersites-com-anthropic-compatible-claude-haiku-4-5-messages-88fd97bc -d '<json body>'
```

Example prompt: Using Claude Haiku 4.5, summarize the following article in three bullet points — system prompt: 'You are a concise summarizer', message: 'Artificial intelligence is rapidly transforming industries...', max_tokens 300.

## When to prefer this

Choose this endpoint when you need the exact Anthropic /v1/messages API shape (so you can point an existing Anthropic SDK with base_url) but want to avoid managing an Anthropic account or API key — authenticating instead via x402 USDC micropayment. Ideal for agents that already have the Anthropic SDK integrated and want keyless pay-per-call access to Claude Haiku 4.5 for short-to-medium text tasks within 16k input chars and 1,024 output tokens.

## Known failure modes

- Payment not included or insufficient USDC — 402 Payment Required returned
- Input text exceeds 16,000 character limit — request rejected or truncated
- max_tokens set above 1,024 — silently clamped to 1,024
- Streaming requested — not supported, will fail or be ignored
- Image or non-text content in messages — text-only endpoint, non-text content rejected
- Invalid Anthropic message format — 400 Bad Request
- Model name other than claude-haiku-4-5 specified — unsupported model error

## How this service works

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.

## Output

Returns an Anthropic-format /v1/messages response object: an assistant message with text content, stop reason, usage token counts, and model identifier — identical shape to what the official Anthropic API returns for the same request.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method",
    "bodyType",
    "body"
   ],
   "properties": {
    "body": {
     "required": [
      "messages"
     ],
     "properties": {
      "model": {
       "type": "string",
       "description": "claude-haiku-4-5 (the only model on this route)"
      },
      "system": {
       "type": "string",
       "description": "optional system prompt (counts toward the input cap)"
      },
      "messages": {
       "type": "array",
       "description": "Anthropic-style messages: [{role, content}], text content only, 16,000 chars total"
      },
      "max_tokens": {
       "type": "number",
       "description": "output cap, clamped to 1,024"
      }
     }
    },
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "POST"
     ],
     "type": "string"
    },
    "bodyType": {
     "enum": [
      "json",
      "form-data",
      "text"
     ],
     "type": "string"
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object",
     "properties": {
      "usage": {
       "type": "object"
      },
      "content": {
       "type": "array",
       "description": "Anthropic-shape content blocks; the answer is content[0].text"
      },
      "stop_reason": {
       "type": "string"
      }
     }
    }
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "id": "msg_...",
  "role": "assistant",
  "type": "message",
  "model": "claude-haiku-4-5",
  "usage": {
   "input_tokens": 18,
   "output_tokens": 24
  },
  "content": [
   {
    "text": "x402 is an open protocol...",
    "type": "text"
   }
  ],
  "stop_reason": "end_turn"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/api-webbersites-com-anthropic-compatible-claude-haiku-4-5-messages-88fd97bc/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.webbersites.com](https://www.zero.xyz/host/api.webbersites.com/llms.txt)