# Fathom Macroeconomic Data API — Category Tree

> Fathom Macroeconomic Data API — Category Tree is a paid API for AI agents from fredfathom.vercel.app, paid per call via x402, $0.04/call, status unknown (last checked 2026-10-11).

Retrieves the hierarchical category tree of FRED economic data series, returning child categories under a given parent category ID

## Facts

- Endpoint: POST https://fredfathom.vercel.app/api/category-tree?utm_source=zero.xyz
- Price: $0.04/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-tree-ec109c04
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_qYEwnNWWYBQDaDDKMpLuT

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-tree-ec109c04 -d '<json body>'
```

Example prompt: Show me the subcategories under FRED's root economic data category so I can figure out which branch covers inflation and price indices.

## When to prefer this

Use this endpoint when you need to programmatically navigate the FRED economic data hierarchy to discover available categories before fetching actual time series data. Prefer this over direct series search when you want to browse by category structure rather than keyword, or when building a category explorer or data discovery workflow on top of FRED's 816,000+ economic series.

## Known failure modes

- Invalid or non-existent categoryId returns an empty children array or error
- Network or upstream FRED API unavailability results in a failed response
- Malformed request body (e.g., non-string categoryId) may return a 400 error
- Rate limiting or payment failures due to x402 protocol may block the request

## 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 the data source name (FRED), the parent category ID, and an array of child category objects each describing a subcategory in the FRED economic data hierarchy. These child categories can be used to further drill down into specific economic time series.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "categoryId": {
   "type": "string",
   "description": "Parent category ID (default: 0 for root)"
  }
 }
}
```

## Response schema (JSON Schema)

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

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/fathom-macroeconomic-data-api-category-tree-ec109c04/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)