# serp402 Duck AI

> serp402 Duck AI is a paid API for AI agents from serp402.com, paid per call via x402, $0.05/call, status unknown (last checked 2026-10-31).

Query DuckDuckGo's AI chat interface and receive AI-generated answers as structured JSON, with support for multi-turn conversations.

## Facts

- Endpoint: POST https://serp402.com/api/v1/duck-ai?utm_source=zero.xyz
- Price: $0.05/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-31
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/serp402-duck-ai-0b7c0d8f
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_TMtQ1gpzoTONSRFmXvtm7

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 serp402-duck-ai-0b7c0d8f -d '<json body>'
```

Example prompt: Ask Duck AI using the claude-haiku-4-5 model: 'What are the main differences between REST and GraphQL APIs?' and give me the answer as JSON.

## When to prefer this

Choose this endpoint when you need AI-generated answers without holding API keys for OpenAI or Anthropic, want to leverage DuckDuckGo's AI chat interface programmatically, need multi-turn conversation support, or want to pay per-call with USDC rather than maintaining a subscription. Especially useful for agents needing quick AI answers at low cost without account setup.

## Known failure modes

- Invalid or unsupported model name returns an error
- Expired or invalid subsequent_request_token breaks conversation continuity
- Empty or malformed query string may return an error or empty response
- Rate limiting or upstream DuckDuckGo unavailability may cause failures
- Payment of 0.05 USDC not fulfilled results in 402 rejection

## How this service works

Duck AI: Duck AI results, returned as JSON. Structured JSON, USD 0.05 per call in USDC — no API key, no account, no subscription, no minimum. Not affiliated with, endorsed by or an official channel of any of the services the results come from. All trademarks and copyright remain the property of their respective owners.

## Output

A structured JSON object containing the AI-generated answer text from DuckDuckGo's Duck AI, the model used, and a subsequent_request_token that can be passed with a new prompt to continue the conversation in the same thread.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "q": {
   "type": "string"
  },
  "model": {
   "type": "string",
   "description": "AI model that answers the prompt. It can be set to: gpt-5.6-luna - GPT-5.6 Luna gpt-6-luna - GPT-6 Luna gpt-5.4-mini - GPT-5.4 mini claude-haiku-4-5 - Claude…"
  },
  "subsequent_request_token": {
   "type": "string",
   "description": "token used to continue a Duck AI conversation. Pass this token with a new q to send a follow-up prompt that includes the previous prompts and answers as…"
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/serp402-duck-ai-0b7c0d8f/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from serp402.com](https://www.zero.xyz/host/serp402.com/llms.txt)