Crypto Fear & Greed Index

[
  {
    "error": "payment required",
    "accepts": [
      {
        "asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
        "extra": {
          "name": "USD Coin",
          "version": "2"
        },
        "payTo": "0x10800a5a5B9d72251566EC651E862A8b4B427dE0",
        "scheme": "exact",
        "network": "base",
        "mimeType": "application/json",
        "resource": "https://api.hergertsynthora.com/v1/fear-greed",
        "description": "SYNTHORA fear-greed: indice de miedo/codicia con la VARIACION frente a ayer y el cruce de banda, no solo el valor. Fuente: alternative.me, fechada y con hash.",
        "outputSchema": {
          "input": {
            "body": {
              "input": "latest"
            },
            "type": "http",
            "method": "POST",
            "bodyType": "json"
          },
          "output": {
            "type": "json",
            "example": {
              "ok": true,
              "niche": "fear_greed",
              "result": {
                "senal": "el indice cambia de 'Extreme Fear' a 'Fear': giro de regimen de sentimiento",
                "value": 27,
                "fuente": "<omitido en el ejemplo publico>",
                "serie_8d": [
                  27,
                  25,
                  "..."
                ],
                "as_of_utc": "2026-08-05T16:31:27Z",
                "maximo_8d": 29,
                "minimo_8d": 25,
                "latencia_s": 0.33,
                "delta_vs_ayer": 2,
                "classification": "Fear",
                "cambio_de_banda": true,
                "clasificacion_ayer": "Extreme Fear"
              }
            }
          }
        },
        "maxAmountRequired": "50000",
        "maxTimeoutSeconds": 60
      }
    ],
    "freeTier": {
      "note": "send header X-WALLET: 0x<your Base address> for a free trial",
      "header": "X-WALLET",
      "callsPerWallet": 3
    },
    "extensions": {
      "bazaar": {
        "info": {
          "input": {
            "body": {
              "input": "latest"
            },
            "type": "http",
            "method": "POST",
            "bodyType": "json"
          },
          "output": {
            "type": "json",
            "example": {
              "ok": true,
              "niche": "fear_greed",
              "result": {
                "senal": "el indice cambia de 'Extreme Fear' a 'Fear': giro de regimen de sentimiento",
                "value": 27,
                "fuente": "<omitido en el ejemplo publico>",
                "serie_8d": [
                  27,
                  25,
                  "..."
                ],
                "as_of_utc": "2026-08-05T16:31:27Z",
                "maximo_8d": 29,
                "minimo_8d": 25,
                "latencia_s": 0.33,
                "delta_vs_ayer": 2,
                "classification": "Fear",
                "cambio_de_banda": true,
                "clasificacion_ayer": "Extreme Fear"
              }
            }
          }
        },
        "schema": {
          "type": "object",
          "$schema": "https://json-schema.org/draft/2020-12/schema",
          "required": [
            "input"
          ],
          "properties": {
            "input": {
              "type": "object",
              "required": [
                "type",
                "method",
                "bodyType",
                "body"
              ],
              "properties": {
                "body": {
                  "type": "object",
                  "required": [
                    "input"
                  ],
                  "properties": {
                    "input": {
                      "type": "string",
                      "description": "SYNTHORA fear-greed: indice de miedo/codicia con la VARIACION frente a ayer y el cruce de banda, no solo el valor. Fuente: alternative.me, fechada y con hash."
                    }
                  }
                },
                "type": {
                  "type": "string",
                  "const": "http"
                },
                "method": {
                  "enum": [
                    "POST",
                    "PUT",
                    "PATCH"
                  ],
                  "type": "string"
                },
                "bodyType": {
                  "enum": [
                    "json",
                    "form-data",
                    "text"
                  ],
                  "type": "string"
                }
              },
              "additionalProperties": false
            },
            "output": {
              "type": "object",
              "required": [
                "type"
              ],
              "properties": {
                "type": {
                  "type": "string"
                },
                "example": {
                  "ok": {
                    "type": "boolean"
                  },
                  "type": "object",
                  "niche": {
                    "type": "string"
                  }
                }
              }
            }
          }
        }
      },
      "delivery": {
        "note": "unlike the signature -- which you verify BEFORE paying -- this one is checked afterwards, on-chain, from your own wallet",
        "order": "compute -> failure gate -> verify -> settle -> deliver",
        "scope": "this covers service FAILURE, not verdict quality",
        "policy": "no-charge-on-service-failure",
        "verify": "after a request of yours FAILS, check your own wallet on Base: no USDC settlement to our payTo will exist for it. If we had charged you, the transfer would be public and permanent",
        "behaviour": "if the service FAILS (invalid input, timeout, stale cache, withdrawn product, malformed output) you receive 402 and are NOT charged"
      },
      "signature": {
        "alg": "ed25519",
        "canon": "json:sort_keys+separators(,:)+ensure_ascii+utf8",
        "verify": "recompute canon from envelope.result, then VerifyKey(bytes.fromhex(pubkey)).verify(canon, bytes.fromhex(sig)) -- no name to trust, verify the signature yourself",
        "jwksUrl": "https://api.hergertsynthora.com/.well-known/jwks.json",
        "envelope": "{result, attestation:{alg,pubkey,sig,canon}}",
        "sigEncoding": "hex(64B raw)",
        "publicKeyUrl": "https://api.hergertsynthora.com/pubkey"
      }
    },
    "x402Version": 1
  }
]