# Obol BTC/USD Spot Price Feed (Signed)

> Obol BTC/USD Spot Price Feed (Signed) 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 the current Bitcoin spot price in USD, cryptographically signed with Ed25519 for independent verification.

## Facts

- Endpoint: GET https://obol-x402.fly.dev/v1/btc/spot
- 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-btc-usd-spot-price-feed-signed-0d8991e8
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_gqsuRMVIEEgmjWsBs9lWW

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-btc-usd-spot-price-feed-signed-0d8991e8
```

Example prompt: What's Bitcoin's current USD spot price? I need a cryptographically signed quote I can independently verify.

## When to prefer this

Choose this endpoint when your agent needs a single, real-time BTC/USD spot price that is cryptographically signed and independently verifiable — ideal for trading bots, audit trails, or any workflow requiring tamper-proof price attestation. Prefer the Trader Bundle sibling endpoint if you also need ETH or mempool data in the same call.

## Known failure modes

- Payment not included or insufficient USDC — returns HTTP 402 requiring x402 payment
- Upstream exchange data unavailable — may return a stale or error response
- Signature verification fails if public key endpoint is unreachable
- Network timeout on fly.dev infrastructure — retry recommended

## How this service works

Bitcoin BTC USD spot price only — single-asset price for trading agents. Cryptographically signed (Ed25519) — every response is independently verifiable via /.well-known/obol-pubkey.

## Output

Returns the current BTC/USD spot price as a single numeric value, accompanied by an Ed25519 cryptographic signature and metadata (timestamp, source exchange). The signature can be independently verified against the public key published 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-btc-usd-spot-price-feed-signed-0d8991e8/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)