Your first request

Mint a key

Create an account and mint a key at beliefsystems.xyz/data. Free, work email, no password, about a minute.The secret is shown once. Put it in your environment:

export BELIEF_API_KEY="belief_live_..."

Call the service index

GET /v1 is the cheapest way to confirm a key works. It answers with every endpoint, the free-tier limits, and your own remaining quota.

curl -s https://api.beliefsystems.xyz/v1 \
  -H "Authorization: Bearer $BELIEF_API_KEY"

{
  "data": {
    "version": "v1",
    "limits": {
      "requestsPerMinute": 60,
      "requestsPerDay": 2000,
      "historyMaxDays": 90,
      "intervals": ["1h", "1d"]
    },
    "key": {
      "prefix": "belief_live_a1b2c3d4",
      "limitMinute": 60,
      "limitDay": 2000,
      "remainingMinute": 59,
      "remainingDay": 1873
    }
  }
}

A 401 here means the key is wrong, not that the endpoint is. Check invalid_api_key.

Read a level

CONFLICT is the Belief Global Conflict Risk Escalation Expectations Index. GET /v1/indices lists every published ticker.

curl -s https://api.beliefsystems.xyz/v1/indices/CONFLICT/latest \
  -H "Authorization: Bearer $BELIEF_API_KEY"

import os
import requests

resp = requests.get(
    "https://api.beliefsystems.xyz/v1/indices/CONFLICT/latest",
    headers={"Authorization": f"Bearer {os.environ['BELIEF_API_KEY']}"},
    timeout=10,
)
resp.raise_for_status()

latest = resp.json()["data"]
print(latest["ticker"], latest["indexLevel"], latest["computedAt"])

const res = await fetch("https://api.beliefsystems.xyz/v1/indices/CONFLICT/latest", {
  headers: { Authorization: `Bearer ${process.env.BELIEF_API_KEY}` },
});
if (!res.ok) throw new Error(`Belief Systems API ${res.status}`);

const { data } = await res.json();
console.log(data.ticker, data.indexLevel, data.computedAt);

{
  "data": {
    "ticker": "CONFLICT",
    "name": "Belief Global Conflict Risk Escalation Expectations Index",
    "computedAt": "2026-08-31T13:44:44.963697Z",
    "indexLevel": "36.11697608",
    "baseIndexLevel": "100.00000000",
    "stale": false,
    "publicStatus": "active",
    "maturityType": "PERPETUAL",
    "methodologyVersion": "midprice-v1",
    "dataQuality": {
      "freshMarketsCount": 24,
      "staleMarketsCount": 0,
      "totalMarketsCount": 24,
      "freshDataPct": 100.0
    }
  },
  "meta": {
    "attribution": "Source: Belief Systems (beliefsystems.xyz)",
    "generatedAt": "2026-08-31T14:01:28.178537Z"
  }
}

Every index is based at 100 on its inception date, so a level reads on its own: CONFLICT at 36.12 is down 63.9% since inception.indexLevel is a decimal string, not a number. Parse it with a decimal type – see Conventions.

Chart the trailing window

History reaches back 90 days, at 1h or 1d. With no parameters you get the full window at 1d.

curl -s "https://api.beliefsystems.xyz/v1/indices/CONFLICT/history?interval=1d" \
  -H "Authorization: Bearer $BELIEF_API_KEY"

import os
from decimal import Decimal

import requests

resp = requests.get(
    "https://api.beliefsystems.xyz/v1/indices/CONFLICT/history",
    params={"interval": "1d"},
    headers={"Authorization": f"Bearer {os.environ['BELIEF_API_KEY']}"},
    timeout=10,
)
resp.raise_for_status()
payload = resp.json()

points = payload["data"]["points"]
first, last = Decimal(points[0]["indexLevel"]), Decimal(points[-1]["indexLevel"])
change = (last / first - 1) * 100

# Label the chart with what you were served, not what you asked for.
window = payload["meta"]
print(f"{window['effectiveStart']} to {window['effectiveEnd']}: {change:+.2f}%")

const url = new URL("https://api.beliefsystems.xyz/v1/indices/CONFLICT/history");
url.searchParams.set("interval", "1d");

const res = await fetch(url, {
  headers: { Authorization: `Bearer ${process.env.BELIEF_API_KEY}` },
});
if (!res.ok) throw new Error(`Belief Systems API ${res.status}`);

const { data, meta } = await res.json();
const first = Number(data.points.at(0).indexLevel);
const last = Number(data.points.at(-1).indexLevel);

// Label the chart with what you were served, not what you asked for.
console.log(meta.effectiveStart, meta.effectiveEnd, `${((last / first - 1) * 100).toFixed(2)}%`);

A start older than 90 days is clamped, not rejected, so a chart that asked for a year still renders. meta.clamped tells you it happened and meta.effectiveStart tells you where the data really begins. Read them before labeling an axis.

Where to go next

Conventions

Decimal strings, timestamps, staleness, and clamping – the four things that surprise people.

Limits and errors

60 per minute, 2,000 per day, and how to back off correctly.

Belief Volatility

What the volatility series measure and how to quote one.

Snapshot bundles

Full history since inception, composition, and weights, as free CSVs.

Common first errors

What you see	What it means
`401 invalid_api_key`	No key, a typo, or a key that was rotated or revoked
`404 not_found`	The ticker is not on this surface. `GET /v1/indices` is the catalog
`422 invalid_interval`	`interval` must be `1h` or `1d`
`429 rate_limited`	Sleep for `Retry-After` seconds, which is exact
CORS failure in a browser	Expected. This API is server-to-server – see Authentication

Get Started

Indices

Belief Volatility

Service

Limits & Errors

Where to go next

Conventions

Limits and errors

Belief Volatility

Snapshot bundles

Common first errors

​Where to go next

Conventions

Limits and errors

Belief Volatility

Snapshot bundles

​Common first errors

Where to go next

Common first errors