# Arkham Altcoin Index

> Arkham Altcoin Index is a paid API for AI agents from api.arkm.com, paid per call via x402, $0.2/call, status unknown (last checked 2026-09-14).

Returns the current Arkham altcoin market index value as a numeric score

## Facts

- Endpoint: POST https://api.arkm.com/x402/marketdata/altcoin-index
- Price: $0.2/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/arkham-altcoin-index-8833d1e7
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_9CCvPFWb15cLgVnjI2YvW

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 arkham-altcoin-index-8833d1e7 -d '<json body>'
```

Example prompt: What's the current Arkham altcoin index right now? I want to see the numeric score they use to track overall altcoin market conditions.

## When to prefer this

Choose this endpoint when you need a single, authoritative numeric index reflecting overall altcoin market conditions as measured by Arkham Intelligence. Ideal for real-time dashboards, trading signal pipelines, or market briefing agents that want a concise altcoin sentiment or momentum score without processing raw price feeds. Prefer this over general crypto price APIs when the Arkham-specific index methodology is desired.

## Known failure modes

- Payment failure if x402 USDC balance is insufficient — returns 402 Payment Required
- Authentication failure if API key is invalid or missing — returns 401 Unauthorized
- Service unavailability if Arkham data pipeline is down — returns 5xx error
- Rate limiting if too many requests are made in a short period — returns 429 Too Many Requests

## How this service works

Get Arkham Altcoin Index. $0.20 per call.

## Output

Returns a JSON object containing a single numeric field `altcoinIndex` (e.g. {"altcoinIndex": 28}), representing the current Arkham altcoin market index value on a numeric scale.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method",
    "bodyType",
    "body"
   ],
   "properties": {
    "body": {
     "type": "object",
     "$schema": "https://json-schema.org/draft/2020-12/schema",
     "properties": {},
     "additionalProperties": {
      "anyOf": [
       {
        "type": "string"
       },
       {
        "type": "number"
       },
       {
        "type": "boolean"
       },
       {
        "type": "array",
        "items": {
         "anyOf": [
          {
           "type": "string"
          },
          {
           "type": "number"
          },
          {
           "type": "boolean"
          }
         ]
        }
       }
      ]
     }
    },
    "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": {
     "type": "object",
     "$schema": "https://json-schema.org/draft/2020-12/schema"
    }
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "altcoinIndex": 28
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/arkham-altcoin-index-8833d1e7/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.arkm.com](https://www.zero.xyz/host/api.arkm.com/llms.txt)