Market Grades
List graded markets
The family document and the current record for every graded market on the newest measurement day. A market whose inputs failed that day stays listed with its last publishable record, so its asOf is earlier; dataStatus and lifecycleState give its standing today.
universeDistribution describes the whole graded universe, whatever limit you pass, so a letter can be read against how populated its band is. Markets below the coverage bar are not graded and do not appear: absence is not an F.
GET
/
v1
/
grades
curl
curl -s "https://api.beliefsystems.xyz/v1/grades?limit=100" \
-H "Authorization: Bearer $BELIEF_API_KEY"import os
import requests
resp = requests.get(
"https://api.beliefsystems.xyz/v1/grades?limit=100",
headers={"Authorization": f"Bearer {os.environ['BELIEF_API_KEY']}"},
timeout=10,
)
resp.raise_for_status()
payload = resp.json()
print(payload["data"])const res = await fetch("https://api.beliefsystems.xyz/v1/grades?limit=100", {
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();
console.log(data);<?php
$curl = curl_init();
curl_setopt_array($curl, [
CURLOPT_URL => "https://api.beliefsystems.xyz/v1/grades",
CURLOPT_RETURNTRANSFER => true,
CURLOPT_ENCODING => "",
CURLOPT_MAXREDIRS => 10,
CURLOPT_TIMEOUT => 30,
CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
CURLOPT_CUSTOMREQUEST => "GET",
CURLOPT_HTTPHEADER => [
"Authorization: Bearer <token>"
],
]);
$response = curl_exec($curl);
$err = curl_error($curl);
curl_close($curl);
if ($err) {
echo "cURL Error #:" . $err;
} else {
echo $response;
}package main
import (
"fmt"
"net/http"
"io"
)
func main() {
url := "https://api.beliefsystems.xyz/v1/grades"
req, _ := http.NewRequest("GET", url, nil)
req.Header.Add("Authorization", "Bearer <token>")
res, _ := http.DefaultClient.Do(req)
defer res.Body.Close()
body, _ := io.ReadAll(res.Body)
fmt.Println(string(body))
}HttpResponse<String> response = Unirest.get("https://api.beliefsystems.xyz/v1/grades")
.header("Authorization", "Bearer <token>")
.asString();require 'uri'
require 'net/http'
url = URI("https://api.beliefsystems.xyz/v1/grades")
http = Net::HTTP.new(url.host, url.port)
http.use_ssl = true
request = Net::HTTP::Get.new(url)
request["Authorization"] = 'Bearer <token>'
response = http.request(request)
puts response.read_body{
"data": {
"asOf": "2026-10-23T00:00:00.000000Z",
"count": 1,
"family": {
"attribution": "Source: Belief Systems (beliefsystems.xyz)",
"calibrationVersion": "mg-cal-1.0",
"disclosureLines": [
"Market Grades measure market quality, not the likelihood of any outcome.",
"Market Grades are unsolicited: no graded party requests, pays for, or previews a grade. Belief Systems holds no positions in graded markets.",
"A grade is not a recommendation to buy, sell, or hold any position, and is not a substitute for a user's own assessment."
],
"familyName": "Market Grades by Belief Systems",
"listed": true,
"methodologyUrl": "https://docs.beliefsystems.xyz/grades/methodology",
"methodologyVersion": "mg-1.2",
"productFamily": "market_grades",
"seasonedObservedDays": 30,
"tierCaps": {
"T0": "C+",
"T1": "B+"
},
"watchUnresolvedDays": 14,
"windowDays": 30
},
"markets": [
{
"asOf": "2026-10-23T00:00:00.000000Z",
"calibrationVersion": "mg-cal-1.0",
"caps": [
{
"binding": true,
"cap_letter": "D",
"lowered_letter": false,
"source": "weakest_link"
},
{
"binding": false,
"cap_letter": "B+",
"lowered_letter": false,
"source": "evidence_tier"
}
],
"computationStatus": "candidate",
"correction": null,
"coverageClass": "full",
"coverageShare": 0.999885,
"dataStatus": "ok",
"disclosureLines": [
"Market Grades measure market quality, not the likelihood of any outcome.",
"Market Grades are unsolicited: no graded party requests, pays for, or previews a grade. Belief Systems holds no positions in graded markets.",
"A grade is not a recommendation to buy, sell, or hold any position, and is not a substitute for a user's own assessment."
],
"evidenceTier": "T1",
"firstObserved": "2026-09-23T10:25:05.936852Z",
"gateFlags": [],
"grade": "D",
"gradeEpisodeId": "polymarket:0x42945ea5657d6f6e77969a06661b29d6f6295083d1ef3479b42efd90647c9dfc:1",
"lastAction": {
"actionType": "grade_established",
"asOf": "2026-10-23T00:00:00.000000Z",
"correctsActionId": null,
"preLaunch": false,
"publishedAt": "2026-10-23T01:39:00.519746Z"
},
"lastConfirmedAction": null,
"lastFullData": "2026-10-23T00:00:00.000000Z",
"lifecycleState": "active",
"marketId": "0x42945ea5657d6f6e77969a06661b29d6f6295083d1ef3479b42efd90647c9dfc",
"methodologyVersion": "mg-1.2",
"observedDaysWindow": 30,
"pillarGrades": {
"integrity": {
"letter": "B+"
},
"liquidity": {
"letter": "F"
}
},
"preLaunch": false,
"question": "Will Ethereum reach $3,500 by December 31, 2026?",
"revision": 0,
"stateRevision": 0,
"venue": "polymarket",
"watch": null,
"window": [
"2026-09-23T00:00:00.000000Z",
"2026-10-23T00:00:00.000000Z"
]
}
],
"productFamily": "market_grades",
"universeDistribution": {
"asOf": "2026-10-23T00:00:00.000000Z",
"byBand": [
{
"band": "A",
"count": 2,
"share": 0.002395
},
{
"band": "B",
"count": 36,
"share": 0.043114
},
{
"band": "C",
"count": 126,
"share": 0.150898
},
{
"band": "D",
"count": 88,
"share": 0.105389
},
{
"band": "F",
"count": 303,
"share": 0.362874
}
],
"byLetter": [
{
"count": 0,
"letter": "A+",
"share": 0
},
{
"count": 0,
"letter": "A",
"share": 0
},
{
"count": 2,
"letter": "A-",
"share": 0.002395
},
{
"count": 7,
"letter": "B+",
"share": 0.008383
},
{
"count": 11,
"letter": "B",
"share": 0.013174
},
{
"count": 18,
"letter": "B-",
"share": 0.021557
},
{
"count": 29,
"letter": "C+",
"share": 0.034731
},
{
"count": 36,
"letter": "C",
"share": 0.043114
},
{
"count": 61,
"letter": "C-",
"share": 0.073054
},
{
"count": 88,
"letter": "D",
"share": 0.105389
},
{
"count": 303,
"letter": "F",
"share": 0.362874
}
],
"notRated": {
"count": 280,
"share": 0.335329
},
"universeSize": 835
},
"universeSize": 835
},
"meta": {
"attribution": "Source: Belief Systems (beliefsystems.xyz)",
"generatedAt": "2026-10-23T15:49:14.582224Z",
"license": "https://beliefsystems.xyz/license",
"termsUrl": "https://beliefsystems.xyz/terms"
}
}{
"error": {
"code": "invalid_api_key",
"docsUrl": "https://docs.beliefsystems.xyz/api-reference/limits#invalid-api-key",
"message": "This endpoint requires a Data API key. Create one free at https://beliefsystems.xyz/data ; programmatic or commercial licensing is at https://beliefsystems.xyz/license.",
"requestId": "9f2c1ad4e6b74c0f8a3d5e1b7c904a26"
}
}{
"error": {
"code": "rate_limited",
"docsUrl": "https://docs.beliefsystems.xyz/api-reference/limits#rate-limited",
"message": "Rate limit exceeded: 60 requests per minute per key.",
"requestId": "9f2c1ad4e6b74c0f8a3d5e1b7c904a26"
}
}{
"error": {
"code": "invalid_api_key",
"docsUrl": "<string>",
"message": "<string>",
"requestId": "<string>"
}
}Authorizations
bearerAuthapiKeyAuth
Your Data API key as a Bearer token: Authorization: Bearer belief_live_.... This is the canonical form. Keys belong on a server, never in a browser.
Query Parameters
Maximum markets to return. 1 to 2000.
Required range:
1 <= x <= 2000⌘I
curl
curl -s "https://api.beliefsystems.xyz/v1/grades?limit=100" \
-H "Authorization: Bearer $BELIEF_API_KEY"import os
import requests
resp = requests.get(
"https://api.beliefsystems.xyz/v1/grades?limit=100",
headers={"Authorization": f"Bearer {os.environ['BELIEF_API_KEY']}"},
timeout=10,
)
resp.raise_for_status()
payload = resp.json()
print(payload["data"])const res = await fetch("https://api.beliefsystems.xyz/v1/grades?limit=100", {
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();
console.log(data);<?php
$curl = curl_init();
curl_setopt_array($curl, [
CURLOPT_URL => "https://api.beliefsystems.xyz/v1/grades",
CURLOPT_RETURNTRANSFER => true,
CURLOPT_ENCODING => "",
CURLOPT_MAXREDIRS => 10,
CURLOPT_TIMEOUT => 30,
CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
CURLOPT_CUSTOMREQUEST => "GET",
CURLOPT_HTTPHEADER => [
"Authorization: Bearer <token>"
],
]);
$response = curl_exec($curl);
$err = curl_error($curl);
curl_close($curl);
if ($err) {
echo "cURL Error #:" . $err;
} else {
echo $response;
}package main
import (
"fmt"
"net/http"
"io"
)
func main() {
url := "https://api.beliefsystems.xyz/v1/grades"
req, _ := http.NewRequest("GET", url, nil)
req.Header.Add("Authorization", "Bearer <token>")
res, _ := http.DefaultClient.Do(req)
defer res.Body.Close()
body, _ := io.ReadAll(res.Body)
fmt.Println(string(body))
}HttpResponse<String> response = Unirest.get("https://api.beliefsystems.xyz/v1/grades")
.header("Authorization", "Bearer <token>")
.asString();require 'uri'
require 'net/http'
url = URI("https://api.beliefsystems.xyz/v1/grades")
http = Net::HTTP.new(url.host, url.port)
http.use_ssl = true
request = Net::HTTP::Get.new(url)
request["Authorization"] = 'Bearer <token>'
response = http.request(request)
puts response.read_body{
"data": {
"asOf": "2026-10-23T00:00:00.000000Z",
"count": 1,
"family": {
"attribution": "Source: Belief Systems (beliefsystems.xyz)",
"calibrationVersion": "mg-cal-1.0",
"disclosureLines": [
"Market Grades measure market quality, not the likelihood of any outcome.",
"Market Grades are unsolicited: no graded party requests, pays for, or previews a grade. Belief Systems holds no positions in graded markets.",
"A grade is not a recommendation to buy, sell, or hold any position, and is not a substitute for a user's own assessment."
],
"familyName": "Market Grades by Belief Systems",
"listed": true,
"methodologyUrl": "https://docs.beliefsystems.xyz/grades/methodology",
"methodologyVersion": "mg-1.2",
"productFamily": "market_grades",
"seasonedObservedDays": 30,
"tierCaps": {
"T0": "C+",
"T1": "B+"
},
"watchUnresolvedDays": 14,
"windowDays": 30
},
"markets": [
{
"asOf": "2026-10-23T00:00:00.000000Z",
"calibrationVersion": "mg-cal-1.0",
"caps": [
{
"binding": true,
"cap_letter": "D",
"lowered_letter": false,
"source": "weakest_link"
},
{
"binding": false,
"cap_letter": "B+",
"lowered_letter": false,
"source": "evidence_tier"
}
],
"computationStatus": "candidate",
"correction": null,
"coverageClass": "full",
"coverageShare": 0.999885,
"dataStatus": "ok",
"disclosureLines": [
"Market Grades measure market quality, not the likelihood of any outcome.",
"Market Grades are unsolicited: no graded party requests, pays for, or previews a grade. Belief Systems holds no positions in graded markets.",
"A grade is not a recommendation to buy, sell, or hold any position, and is not a substitute for a user's own assessment."
],
"evidenceTier": "T1",
"firstObserved": "2026-09-23T10:25:05.936852Z",
"gateFlags": [],
"grade": "D",
"gradeEpisodeId": "polymarket:0x42945ea5657d6f6e77969a06661b29d6f6295083d1ef3479b42efd90647c9dfc:1",
"lastAction": {
"actionType": "grade_established",
"asOf": "2026-10-23T00:00:00.000000Z",
"correctsActionId": null,
"preLaunch": false,
"publishedAt": "2026-10-23T01:39:00.519746Z"
},
"lastConfirmedAction": null,
"lastFullData": "2026-10-23T00:00:00.000000Z",
"lifecycleState": "active",
"marketId": "0x42945ea5657d6f6e77969a06661b29d6f6295083d1ef3479b42efd90647c9dfc",
"methodologyVersion": "mg-1.2",
"observedDaysWindow": 30,
"pillarGrades": {
"integrity": {
"letter": "B+"
},
"liquidity": {
"letter": "F"
}
},
"preLaunch": false,
"question": "Will Ethereum reach $3,500 by December 31, 2026?",
"revision": 0,
"stateRevision": 0,
"venue": "polymarket",
"watch": null,
"window": [
"2026-09-23T00:00:00.000000Z",
"2026-10-23T00:00:00.000000Z"
]
}
],
"productFamily": "market_grades",
"universeDistribution": {
"asOf": "2026-10-23T00:00:00.000000Z",
"byBand": [
{
"band": "A",
"count": 2,
"share": 0.002395
},
{
"band": "B",
"count": 36,
"share": 0.043114
},
{
"band": "C",
"count": 126,
"share": 0.150898
},
{
"band": "D",
"count": 88,
"share": 0.105389
},
{
"band": "F",
"count": 303,
"share": 0.362874
}
],
"byLetter": [
{
"count": 0,
"letter": "A+",
"share": 0
},
{
"count": 0,
"letter": "A",
"share": 0
},
{
"count": 2,
"letter": "A-",
"share": 0.002395
},
{
"count": 7,
"letter": "B+",
"share": 0.008383
},
{
"count": 11,
"letter": "B",
"share": 0.013174
},
{
"count": 18,
"letter": "B-",
"share": 0.021557
},
{
"count": 29,
"letter": "C+",
"share": 0.034731
},
{
"count": 36,
"letter": "C",
"share": 0.043114
},
{
"count": 61,
"letter": "C-",
"share": 0.073054
},
{
"count": 88,
"letter": "D",
"share": 0.105389
},
{
"count": 303,
"letter": "F",
"share": 0.362874
}
],
"notRated": {
"count": 280,
"share": 0.335329
},
"universeSize": 835
},
"universeSize": 835
},
"meta": {
"attribution": "Source: Belief Systems (beliefsystems.xyz)",
"generatedAt": "2026-10-23T15:49:14.582224Z",
"license": "https://beliefsystems.xyz/license",
"termsUrl": "https://beliefsystems.xyz/terms"
}
}{
"error": {
"code": "invalid_api_key",
"docsUrl": "https://docs.beliefsystems.xyz/api-reference/limits#invalid-api-key",
"message": "This endpoint requires a Data API key. Create one free at https://beliefsystems.xyz/data ; programmatic or commercial licensing is at https://beliefsystems.xyz/license.",
"requestId": "9f2c1ad4e6b74c0f8a3d5e1b7c904a26"
}
}{
"error": {
"code": "rate_limited",
"docsUrl": "https://docs.beliefsystems.xyz/api-reference/limits#rate-limited",
"message": "Rate limit exceeded: 60 requests per minute per key.",
"requestId": "9f2c1ad4e6b74c0f8a3d5e1b7c904a26"
}
}{
"error": {
"code": "invalid_api_key",
"docsUrl": "<string>",
"message": "<string>",
"requestId": "<string>"
}
}