# Fathom Macroeconomic Data API — Tag Series Lookup

> Fathom Macroeconomic Data API — Tag Series Lookup is a paid API for AI agents from fredthom.vercel.app, paid per call via x402, $0.4/call, status unknown (last checked 2026-09-15).

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

## Facts

- Endpoint: POST https://fredthom.vercel.app/api/tag-series
- Price: $0.4/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-tag-series-lookup-f2a12647
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_VO-HwFudELXONQNLxR9DP

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-lookup-f2a12647 -d '<json body>'
```

Example prompt: Using Fathom's FRED-powered API, find me up to 30 economic time series tagged with 'inflation' so I can see what data is available.

## When to prefer this

Use this endpoint when you need to discover and browse economic time series by topic or category tag from FRED's 816,000+ series catalog. Ideal for exploratory research into what macroeconomic data is available before fetching actual time series values. Choose this over a general FRED API when you want a simplified, pre-paid per-call interface without managing API keys.

## Known failure modes

- Invalid or unknown tag returns empty series array
- Missing required 'tag' field returns validation error
- Limit parameter not a valid string number may cause unexpected results
- FRED upstream unavailability causes service errors
- Payment failure (402) if USDC balance is insufficient

## 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 series objects (each with series metadata), and the data source identifier. Defaults to 20 results unless limit is specified.

## 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-lookup-f2a12647/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from fredthom.vercel.app](https://www.zero.xyz/host/fredthom.vercel.app/llms.txt)