# ChainScope Fee Estimator

> ChainScope Fee Estimator is a paid API for AI agents from chainsscope.duckdns.org, paid per call via x402, $0.01/call, status unknown (last checked 2026-09-14).

Estimates current transaction fees (gas prices) for a specified blockchain network, returning fast, standard, and slow fee tiers in the appropriate unit.

## Facts

- Endpoint: POST https://chainsscope.duckdns.org/tools/fee-estimate
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/chainscope-fee-estimator-45dcb637
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_B0rhFi3OpgULzCDg0xBkU

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 chainscope-fee-estimator-45dcb637 -d '<json body>'
```

Example prompt: What are the current gas fees on Ethereum right now — give me the fast, standard, and slow tiers so I can decide how to price my transaction?

## When to prefer this

Use this endpoint when you need a consistent, multi-chain fee estimation interface across Ethereum, Base, Bitcoin, and Solana without building separate integrations for each network. Prefer it when your agent needs to make fee-aware decisions (e.g. choosing fast vs. slow tier) before submitting a transaction, or when routing transactions across chains based on current fee levels.

## Known failure modes

- Unsupported chain identifier returns an error or null fee fields
- Network congestion or RPC downtime may return null for one or more fee tiers
- Missing or malformed chain parameter causes a 400-level error
- Fees may be stale if the underlying node data is delayed

## How this service works

Current network fee conditions -- gas price (ETH/Base/Arbitrum/Optimism/Polygon), sat/vB fee tiers (Bitcoin), or recent prioritization fees (Solana) -- useful for an agent about to construct a transaction itself.

## Output

A JSON object containing fee estimates broken down into fast, standard, and slow tiers (some may be null if unavailable), the unit the fees are expressed in (e.g. 'gwei' for Ethereum), and the chain identifier confirming which network was queried.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "chain": {
   "enum": [
    "ethereum",
    "base",
    "bitcoin",
    "solana",
    "arbitrum",
    "optimism",
    "polygon"
   ],
   "type": "string"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "fast": null,
  "slow": null,
  "unit": "gwei",
  "chain": "ethereum",
  "standard": "5"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/chainscope-fee-estimator-45dcb637/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from chainsscope.duckdns.org](https://www.zero.xyz/host/chainsscope.duckdns.org/llms.txt)