# CoinCap EMA (Exponential Moving Average)

> CoinCap EMA (Exponential Moving Average) is a paid API for AI agents from rest.coincap.io, paid per call via x402, $0.004/call, status unknown (last checked 2026-09-13).

Returns the Exponential Moving Average (EMA) technical indicator for a given cryptocurrency asset slug.

## Facts

- Endpoint: GET https://rest.coincap.io/v3/agentFriendly/ta/%7Bslug%7D/ema
- Price: $0.004/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-13
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/coincap-ema-exponential-moving-average-c81b1d68
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_qZ72byRQPSTrxExuu9VfT

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 coincap-ema-exponential-moving-average-c81b1d68
```

Example prompt: Can you pull the exponential moving average (EMA) for Bitcoin from CoinCap so I can see where the price trend is sitting right now?

## When to prefer this

Choose this endpoint when you need EMA-specific technical analysis for a cryptocurrency asset and want a pre-computed, ready-to-use indicator rather than raw price history to calculate yourself. Ideal for trading bots, portfolio monitors, or market research tools that rely on EMA crossover signals. Prefer it over general price endpoints when trend-smoothing analysis is required. It supports keyless per-call USDC payment via x402, making it ideal for agents that can't pre-register API keys.

## Known failure modes

- Invalid or unrecognized asset slug returns an error or empty result
- Payment failure via x402 protocol blocks access without a valid API key fallback
- Network timeout on the REST endpoint
- Missing required 'slug' parameter causes a 400 Bad Request
- Stale or insufficient historical data for a very new or illiquid asset may produce unreliable EMA values

## How this service works

CoinCap gives AI agents, apps, and developers real-time cryptocurrency market data.

Two ways to access:
- **API key** — sign up at https://coincap.io and pass `Authorization: Bearer <key>` or `?apiKey=<key>`.
- **Keyless x402** (agents) — the 10 `agentFriendly` endpoints accept per-call USDC payment on Base via the [x402 protocol](https://x402.gitbook.io/x402). No signup needed. See `/.well-known/x402.json` for the machine-readable payment catalog.

## Output

Returns EMA (Exponential Moving Average) technical indicator values for the requested cryptocurrency asset, including the computed moving average figure derived from historical price data, enabling trend analysis and trading signal evaluation.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "required": [
  "slug"
 ],
 "properties": {
  "slug": {
   "type": "string"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "object"
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/coincap-ema-exponential-moving-average-c81b1d68/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from rest.coincap.io](https://www.zero.xyz/host/rest.coincap.io/llms.txt)