# PennyRail Word Frequency / Term Frequency Analyzer

> PennyRail Word Frequency / Term Frequency Analyzer is a paid API for AI agents from pennyrail.vercel.app, paid per call via x402, $0.001/call, status unknown (last checked 2026-09-14).

Computes word frequency (term frequency) counts for all tokens in a given text input

## Facts

- Endpoint: POST https://pennyrail.vercel.app/api/p/nano/text.word-frequency--term-frequency
- Price: $0.001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/pennyrail-word-frequency-term-frequency-analyzer-56f253b6
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_JReMa1I2QQhSlM-ID89xP

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 pennyrail-word-frequency-term-frequency-analyzer-56f253b6 -d '<json body>'
```

Example prompt: Can you count how often each word appears in this paragraph? 'The quick brown fox jumps over the lazy dog. The dog barked at the fox.'

## When to prefer this

Choose this endpoint when you need a lightweight, pay-per-use word frequency computation without setting up your own NLP pipeline. It is ideal for one-off document analysis, preprocessing steps for TF-IDF, or when you want a serverless micro-service approach at $0.001 per call. Prefer alternatives if you need advanced NLP (stemming, lemmatization, stop-word removal) or batch processing of many documents simultaneously.

## Known failure modes

- Empty or missing 'input' field returns a validation error
- Extremely long texts may time out or be truncated
- Non-UTF-8 encoded text may cause parsing errors
- Punctuation handling and tokenization behavior may differ from expectations (e.g. hyphenated words)
- Rate limiting or payment failure returns 402 if USDC balance is insufficient

## How this service works

Machine-readable settlement service

## Output

A JSON object mapping each unique word (token) found in the input text to its occurrence count or frequency score, enabling downstream NLP tasks such as TF-IDF computation, keyword analysis, or vocabulary profiling.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "string"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "object",
 "additionalProperties": true
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/pennyrail-word-frequency-term-frequency-analyzer-56f253b6/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from pennyrail.vercel.app](https://www.zero.xyz/host/pennyrail.vercel.app/llms.txt)