Sentiment analysis API: positive or negative with confidence score

$0.01 per call · failed calls are never charged · no account or subscription: pay per call with a card key or USDC

Positive or negative sentiment of English text with a confidence score, from a DistilBERT model fine-tuned on SST-2. Use to triage reviews, support messages, social posts and replies.

When to use it

Run it free (25 free calls) Buy credits by card (from $1) Example result (JSON)

Try it with your own inputs

English text, up to 4,000 characters

Uses one of your 25 free calls. Nothing is charged, and a call that fails is not counted.

Inputs

NameTypeDescription
text (required)stringEnglish text, up to 4,000 characters

Request

Over HTTP, with a card key from /credits:

curl -H "Authorization: Bearer adt_…" "https://tools.funwords.eu/ai/sentiment?text=The%20checkout%20was%20fast%20and%20support%20answered%20within%20minutes."

Or one of your 25 free calls, no key:

curl "https://tools.funwords.eu/ai/sentiment?text=The%20checkout%20was%20fast%20and%20support%20answered%20within%20minutes.&trial=1"

Without a key, the same URL answers 402 Payment Required with x402 and MPP terms, so an agent with a wallet pays per call in USDC (Base, Polygon, Arbitrum or Solana over x402; Base or Tempo over MPP) and retries.

Example result

{
  "label": "POSITIVE",
  "score": 0.9987,
  "scores": {
    "POSITIVE": 0.9987,
    "NEGATIVE": 0.0013
  },
  "model": "@cf/huggingface/distilbert-sst-2-int8"
}

From an AI agent (MCP)

Add the MCP server to Claude, Cursor or any MCP client. This tool is ai_sentiment, and the first 25 successful calls are free:

https://tools.funwords.eu/mcp

Questions

Which model and languages?

A DistilBERT model fine-tuned on SST-2, for English text up to 4,000 characters.

Is there a neutral class?

No, positive or negative only, each with its score.

How do I pay?

Each successful call costs $0.01; failed calls are not charged. The first 25 calls are free. Then pay with card credits (from $1; the key goes in an Authorization header or, for clients that can only fetch a URL, as api_key= in the URL) or per call in USDC over x402 or MPP. No account is needed.

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