# US Core CPI Year-Over-Year Inflation Rate (FRED CPILFESL)

> US Core CPI Year-Over-Year Inflation Rate (FRED CPILFESL) is a paid API for AI agents from finance-api.kdlcfa.workers.dev, paid per call via x402, $0.01/call, status unknown (last checked 2026-09-15).

Returns the latest US Core CPI (excluding food & energy) year-over-year inflation rate sourced from FRED's CPILFESL series

## Facts

- Endpoint: GET https://finance-api.kdlcfa.workers.dev/core-cpi-us
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/us-core-cpi-year-over-year-inflation-rate-fred-cpilfesl-37b6bf7b
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_MI8RW3aejs4knK-etpOVE

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 us-core-cpi-year-over-year-inflation-rate-fred-cpilfesl-37b6bf7b
```

Example prompt: What is the latest US core CPI inflation rate right now — that's CPI excluding food and energy, year-over-year from FRED?

## When to prefer this

Choose this endpoint when you need the US Core CPI (ex food & energy) specifically — the inflation measure most closely watched by the Federal Reserve for policy decisions. Prefer it over headline CPI endpoints when you want to exclude volatile food and energy price swings to assess underlying inflation trends. Ideal for macro research, Fed policy analysis, and economic dashboards requiring a single clean figure from the authoritative FRED data source.

## Known failure modes

- FRED API unavailable or rate-limited — worker may return 500 or stale data
- Data not yet updated for the current month — most recent value may lag by 2-4 weeks after CPI release
- Payment not completed (x402) — returns 402 Payment Required if USDC payment is not attached
- Network timeout from Cloudflare Worker to FRED upstream

## How this service works

US Core CPI (excluding food & energy) year-over-year inflation rate, via FRED (CPILFESL)

## Output

Returns the latest US Core CPI year-over-year percentage change (CPILFESL series from FRED), representing inflation in consumer prices excluding volatile food and energy components, along with the associated reporting date or period.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "required": [],
     "properties": {}
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/us-core-cpi-year-over-year-inflation-rate-fred-cpilfesl-37b6bf7b/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
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