# Oblique Markets Echo Service

> Oblique Markets Echo Service is a paid API for AI agents from oblique.markets, paid per call via x402, $0.01/call, status unknown (last checked 2026-10-11).

Returns any query parameters passed to it verbatim, functioning as an HTTP echo endpoint for testing and validation.

## Facts

- Endpoint: GET https://oblique.markets/api/v1/paid/echo?utm_source=zero.xyz
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-11
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/oblique-markets-echo-service-ed0699f9
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_jdbc0JP8q6LzjadMWlTMn

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 oblique-markets-echo-service-ed0699f9
```

Example prompt: Send a test GET request to the Oblique Markets echo endpoint with a query parameter called 'hello' set to 'world' and tell me what it sends back — I want to confirm the x402 payment flow and parameter passthrough are working.

## When to prefer this

Choose this endpoint when you need to verify that an x402-gated HTTP call can be made successfully from your agent runtime, or when you want to confirm that query parameters pass through correctly without side effects. It is the simplest possible paid endpoint on the Oblique Markets platform, making it ideal for integration smoke tests and payment-flow validation before calling more complex services.

## Known failure modes

- Missing or invalid x402 payment header results in a 402 Payment Required response
- Malformed query parameters may not be reflected if they violate URL encoding rules
- Network errors or server unavailability return standard HTTP 5xx responses
- Using POST or PUT HTTP methods returns an error since only GET, HEAD, and DELETE are accepted

## How this service works

Echo service

## Output

The endpoint returns the query parameters passed to it verbatim, effectively mirroring back whatever key-value pairs were included in the request. This allows callers to confirm that their parameters arrived at the server intact and that the x402 payment and HTTP transport layers are functioning correctly.

## 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"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET",
      "HEAD",
      "DELETE"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "properties": {},
     "description": "Any query parameters; they are returned verbatim."
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "properties": {
    "echo": {
     "type": "object",
     "properties": {
      "n": {
       "type": "string"
      },
      "hello": {
       "type": "string"
      }
     }
    },
    "message": {
     "type": "string"
    },
    "timestamp": {
     "type": "string"
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/oblique-markets-echo-service-ed0699f9/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from oblique.markets](https://www.zero.xyz/host/oblique.markets/llms.txt)