# Obol USDT/USD Spot Price Feed

> Obol USDT/USD Spot Price Feed is a paid API for AI agents from obol-x402.fly.dev, paid per call via x402, $0.01/call, status down (last checked 2026-09-15).

Returns a cryptographically signed USDT/USD spot price quote aggregated from Coinbase and Kraken, including a stablecoin peg divergence flag.

## Facts

- Endpoint: GET https://obol-x402.fly.dev/v1/price/USDT
- Price: $0.01/call
- Payment: x402
- Status: down
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/obol-usdt-usd-spot-price-feed-d884f579
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_x7J5RI_Xq6-WYCnHK_rEc

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 obol-usdt-usd-spot-price-feed-d884f579
```

Example prompt: What's the current USDT/USD spot price right now — is Tether holding its peg, or is there any divergence flagged across Coinbase and Kraken?

## When to prefer this

Use this endpoint when you need a cryptographically verifiable USDT/USD price with peg divergence detection from multiple exchanges (Coinbase + Kraken). Prefer over generic price APIs when auditability and tamper-evidence matter, or when you need to detect stablecoin de-peg events programmatically for an AI agent workflow.

## Known failure modes

- Exchange API unavailability causes stale or missing price data
- Payment of $0.01 USDC not included or rejected via x402 protocol results in 402 Payment Required
- Network timeout to fly.dev host returns 5xx error
- Signature verification failure if public key mismatch or response tampered in transit

## How this service works

USDT USD spot price stablecoin quote Coinbase Kraken with divergence flag. Single-asset USDT/USD for AI agents. Cryptographically signed (Ed25519) — every response is independently verifiable via /.well-known/obol-pubkey.

## Output

Returns the current USDT/USD spot price aggregated from Coinbase and Kraken, a boolean or flag indicating stablecoin peg divergence, a timestamp, and an Ed25519 cryptographic signature that can be independently verified against the public key at /.well-known/obol-pubkey.

## 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": {}
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/obol-usdt-usd-spot-price-feed-d884f579/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from obol-x402.fly.dev](https://www.zero.xyz/host/obol-x402.fly.dev/llms.txt)