# LimitGuard API Key Upgrade to Starter Tier

> LimitGuard API Key Upgrade to Starter Tier is a paid API for AI agents from api.limitguard.ai, paid per call via x402, $99/call, status unknown (last checked 2026-10-11).

Upgrades an API key to the LimitGuard Starter tier, enabling access to real-time trust scoring across up to 8 data sources for AI agents, businesses, and transactions.

## Facts

- Endpoint: GET https://api.limitguard.ai/v1/keys/upgrade/starter?utm_source=zero.xyz
- Price: $99/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-11
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/limitguard-api-key-upgrade-to-starter-tier-8eee2a37
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_XkNQd7OBXfXqQqrT031mN

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 limitguard-api-key-upgrade-to-starter-tier-8eee2a37
```

Example prompt: Upgrade my LimitGuard API key to the Starter tier so I can start running real-time trust scores across all 8 data sources for my agents and transactions.

## When to prefer this

Use this endpoint when you need to upgrade a LimitGuard API key from a free or limited tier to the Starter plan to gain access to multi-source trust scoring. Prefer this over manually managing subscriptions or contacting support.

## Known failure modes

- Insufficient prepaid balance — returns payment required error with top-up instructions
- Already on Starter or higher tier — may return a no-op or conflict response
- Invalid or missing API key — authentication failure
- Service unavailable — transient API error

## How this service works

Check every lead against official business registers, VAT and sanctions lists. Proceed, review or block, with the source. 5 lead checks free.

## Output

Returns a JSON object with status 'ok' confirming the API key has been successfully upgraded to the Starter tier, granting access to real-time trust scoring across up to 8 data sources.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "note": {
   "type": "string"
  },
  "input": {
   "type": "object",
   "$schema": "https://json-schema.org/draft/2020-12/schema",
   "required": [],
   "properties": {}
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  },
  "sandbox": {
   "type": "object",
   "required": [
    "url"
   ],
   "properties": {
    "url": {
     "type": "string"
    },
    "curl": {
     "type": "string"
    },
    "note": {
     "type": "string"
    }
   }
  },
  "recovery": {
   "type": "object",
   "required": [
    "url"
   ],
   "properties": {
    "url": {
     "type": "string"
    },
    "curl": {
     "type": "string"
    }
   }
  },
  "prepaidBalance": {
   "type": "object",
   "required": [
    "balance_usd",
    "price_usd"
   ],
   "properties": {
    "note": {
     "type": "string"
    },
    "topup": {
     "type": "object",
     "required": [
      "url"
     ],
     "properties": {
      "url": {
       "type": "string"
      },
      "curl": {
       "type": "string"
      },
      "minimum_usd": {
       "type": "integer"
      }
     }
    },
    "reason": {
     "type": "string"
    },
    "price_usd": {
     "type": "number"
    },
    "balance_usd": {
     "type": [
      "number",
      "null"
     ]
    }
   }
  },
  "documentation_url": {
   "type": "string"
  },
  "cachedTierAvailable": {
   "type": "boolean"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "status": "ok"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/limitguard-api-key-upgrade-to-starter-tier-8eee2a37/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.limitguard.ai](https://www.zero.xyz/host/api.limitguard.ai/llms.txt)