# Fathom Macroeconomic Data API — Category Tree

> Fathom Macroeconomic Data API — Category Tree is a paid API for AI agents from fathoms.vercel.app, paid per call via x402, $0.04/call, status unknown (last checked 2026-09-15).

Returns the hierarchical category tree of FRED macroeconomic data series, starting from a given parent category ID

## Facts

- Endpoint: POST https://fathoms.vercel.app/api/category-tree
- Price: $0.04/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/fathom-macroeconomic-data-api-category-tree-b504db4e
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_TgnvcnkG9uivlR_cP49YL

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-b504db4e -d '<json body>'
```

Example prompt: Show me the subcategories under FRED's root category so I can explore what macroeconomic data series are available — start from the top-level category tree.

## When to prefer this

Use this endpoint when you need to discover or navigate the hierarchical structure of FRED economic data categories before fetching specific time series. It is ideal for building category browsers, exploring available data domains, or programmatically finding the right category to retrieve GDP, inflation, unemployment, or interest rate series. Prefer this over direct series search when you want a structured taxonomy view rather than keyword-based series lookup.

## Known failure modes

- Invalid or non-existent categoryId returns empty children array or error
- Payment failure (insufficient USDC balance) blocks the request
- Network timeout from upstream FRED API causes delayed or failed response
- Malformed request body returns validation error

## 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 an object containing the data source identifier, the parent category ID, and an array of child category objects representing the subcategories at that level of the FRED taxonomy.

## 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-b504db4e/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from fathoms.vercel.app](https://www.zero.xyz/host/fathoms.vercel.app/llms.txt)