# Fathom Macroeconomic Data API — Category Series

> Fathom Macroeconomic Data API — Category Series is a paid API for AI agents from fredfathom.vercel.app, paid per call via x402, $0.06/call, status unknown (last checked 2026-10-11).

Returns a list of FRED economic data series belonging to a specified FRED category ID

## Facts

- Endpoint: POST https://fredfathom.vercel.app/api/category-series?utm_source=zero.xyz
- Price: $0.06/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-11
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/fathom-macroeconomic-data-api-category-series-18e42aa9
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_RESXj8Bwif6At-hiTG_se

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 fathom-macroeconomic-data-api-category-series-18e42aa9 -d '<json body>'
```

Example prompt: Pull up to 50 economic time series listed under FRED category 32991 — I want to see what GDP-related series are available there.

## When to prefer this

Use this endpoint when you need to discover or enumerate available FRED economic time series within a known FRED category — for example, to browse what GDP, inflation, unemployment, or interest rate series exist before fetching actual observations. Prefer this over a general search when you already know the FRED category ID and want a structured list of its series. This is a discovery/browsing step, not for fetching time series data values themselves.

## Known failure modes

- Invalid or nonexistent categoryId returns empty series array or error
- Omitting required categoryId field causes a 400/validation error
- Limit parameter out of range or non-numeric may cause unexpected results
- Upstream FRED API outage may cause degraded or failed responses
- Rate limiting or payment failures may block access

## How this service works

Free macroeconomic data API powered by FRED. 816,000+ economic time series. GDP, inflation, unemployment, interest rates, and more.

## Output

Returns a JSON object containing an array of economic time series objects (each with series metadata such as ID, name, frequency, units, and observation range), the source attribution, and the queried category ID. The series array is paginated by the limit parameter.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "required": [
  "categoryId"
 ],
 "properties": {
  "limit": {
   "type": "string",
   "description": "Max results (default: 20)"
  },
  "categoryId": {
   "type": "string",
   "description": "FRED category ID"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "object",
 "required": [
  "source"
 ],
 "properties": {
  "series": {
   "type": "array",
   "items": {
    "type": "object"
   }
  },
  "source": {
   "type": "string"
  },
  "category_id": {
   "type": "string"
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/fathom-macroeconomic-data-api-category-series-18e42aa9/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from fredfathom.vercel.app](https://www.zero.xyz/host/fredfathom.vercel.app/llms.txt)