# Fathom Macroeconomic Data API — Tag Series Search

> Fathom Macroeconomic Data API — Tag Series Search is a paid API for AI agents from fathom-opal.vercel.app, paid per call via x402, $0.06/call, status unknown (last checked 2026-09-14).

Returns a list of FRED economic time series filtered by a given tag (e.g. 'gdp', 'inflation', 'monthly', 'nsa')

## Facts

- Endpoint: POST https://fathom-opal.vercel.app/api/tag-series
- Price: $0.06/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/fathom-macroeconomic-data-api-tag-series-search-eea81ceb
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_HbiPQpMmhIo9Uakzwh0zk

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-eea81ceb -d '<json body>'
```

Example prompt: Search Fathom's FRED-powered macroeconomic database for all time series tagged 'inflation' and show me up to 30 results.

## When to prefer this

Use this endpoint when you need to discover which FRED economic time series exist under a given thematic tag (e.g. 'gdp', 'inflation', 'nsa', 'monthly') before fetching actual data values. It is ideal for browsing and cataloging available series by topic rather than retrieving specific observations. Prefer this over direct FRED API access when you want a lightweight, pay-per-call interface with no API key management.

## Known failure modes

- Missing required 'tag' field returns a validation error
- Unknown or misspelled tag returns an empty series array
- Limit parameter passed as non-numeric string may cause unexpected results
- Rate limiting or payment failure (x402) blocks the request
- FRED upstream outage may cause downstream failures

## 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 queried tag name, an array of matching FRED economic time series objects (each with series metadata such as ID, title, frequency, units, and observation range), and a source field indicating the data provider.

## 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-eea81ceb/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from fathom-opal.vercel.app](https://www.zero.xyz/host/fathom-opal.vercel.app/llms.txt)