# Fathom Macroeconomic Data API — Tag Series Search

> Fathom Macroeconomic Data API — Tag Series Search is a paid API for AI agents from fsthum.vercel.app, paid per call via x402, $0.4/call, status unknown (last checked 2026-10-29).

Retrieves a list of FRED economic time series that match a given tag (e.g. 'gdp', 'inflation', 'monthly', 'nsa'), returning up to a configurable number of results.

## Facts

- Endpoint: POST https://fsthum.vercel.app/api/tag-series?utm_source=zero.xyz
- Price: $0.4/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-29
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/fathom-macroeconomic-data-api-tag-series-search-75995a75
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_SXiY1zmRDCHLkDw1Tfhqf

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-tag-series-search-75995a75 -d '<json body>'
```

Example prompt: Search FRED for all economic time series tagged 'inflation' and give me up to 30 results.

## When to prefer this

Use this endpoint when you need to discover or enumerate FRED economic time series by topic tag before fetching actual data values. Ideal for building a catalog of available datasets, letting users browse economic indicators by category, or identifying the right series ID to query next. Prefer this over direct series lookup when you don't know the exact FRED series ID but know the economic concept or frequency (e.g. 'gdp', 'monthly', 'inflation').

## Known failure modes

- Invalid or unrecognized tag returns empty series array
- Missing required 'tag' field causes a 400/validation error
- Limit parameter ignored or out-of-range may default to 20
- FRED upstream service unavailability causes 502/timeout
- Overly broad tags may return truncated or generic results

## 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 tag used for the query, an array of matching FRED economic time series objects (each with series metadata), and the data source identifier. The series array contains structured information about each matching dataset.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "required": [
  "tag"
 ],
 "properties": {
  "tag": {
   "type": "string",
   "description": "Tag name (e.g. gdp, monthly, inflation, nsa)"
  },
  "limit": {
   "type": "string",
   "description": "Max results (default: 20)"
  }
 }
}
```

## Response schema (JSON Schema)

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

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/fathom-macroeconomic-data-api-tag-series-search-75995a75/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from fsthum.vercel.app](https://www.zero.xyz/host/fsthum.vercel.app/llms.txt)