Sentiment Analyzer API

![MCP Server](https://sentiment-analyzer.api.klymax402.com/mcp) ![x402](https://x402.org) ![License: MIT](LICENSE)

Sentiment analysis with emotion detection, confidence scores, and key phrase extraction. Single or batch mode. Pay-per-call via x402 (USDC on Base L2) -- no API key, no signup, no rate-limit wall.

Part of the klymax402 marketplace -- 100 x402 micropayment APIs for AI agents, one wallet, USDC on Base.

Quickstart -- MCP

Add to your MCP client config (Claude Desktop, Cursor, ElizaOS, etc.):

{
  "mcpServers": {
    "sentiment-analyzer": {
      "url": "https://sentiment-analyzer.api.klymax402.com/mcp"
    }
  }
}

Quickstart -- HTTP (x402)

curl -X POST "https://sentiment-analyzer.api.klymax402.com/api/analyze" \
  -H "Content-Type: application/json" \
  -d '{"text":"..."}'
# -> 402 Payment Required, with an x402 payment challenge in the response body

Any x402-aware client (@x402/fetch, x402-agent-tools, ATXP) handles the 402 -> sign -> retry cycle automatically.

Tools

| Tool | Method | Path | Price | Description | |---|---|---|---|---| | text_analyze_sentiment | POST | /api/analyze | $0.015 | Analyze sentiment of a single text | | text_analyze_sentiment_batch | POST | /api/analyze/batch | $0.10 | Analyze sentiment of up to 20 texts in batch |

`text_analyze_sentiment`

Use this when you need to determine the emotional tone and sentiment of text. Returns structured sentiment analysis with emotion breakdown and key drivers.

Parameters

| Name | Type | Required | Description | |---|---|---|---| | text | string | yes | The text to analyze for sentiment |

Returns

sentiment -- overall sentiment label (positive, negative, neutral)
confidence -- confidence score 0-100
emotions -- detected emotions with scores (joy, anger, fear, surprise, sadness)
keyPhrases -- array of phrases driving the sentiment
score -- numeric sentiment score from -1.0 (negative) to 1.0 (positive)

Example response:

{"sentiment":"positive","confidence":87,"score":0.73,"emotions":{"joy":0.82,"surprise":0.15,"anger":0.01,"fear":0.01,"sadness":0.01},"keyPhrases":["excellent results","exceeded expectations"]}

When to use: responding to customer feedback, reviews, or social media mentions. Essential for brand monitoring, support ticket triage, and content tone analysis.

`text_analyze_sentiment_batch`

Use this when you need to analyze sentiment of multiple texts at once (up to 20). Returns an array of individual sentiment results in one call.

Parameters

| Name | Type | Required | Description | |---|---|---|---| | texts | array | yes | Array of texts to analyze (max 20) |

Returns

results -- array of sentiment objects, one per input text
averageSentiment -- overall average sentiment score across all texts
distribution -- count of positive/negative/neutral texts

Example response:

{"results":[{"sentiment":"positive","confidence":91,"score":0.8},{"sentiment":"negative","confidence":74,"score":-0.6}],"averageSentiment":0.1,"distribution":{"positive":1,"negative":1,"neutral":0}}

When to use: bulk analysis of reviews, survey responses, or social media feeds. Essential when comparing sentiment across multiple data points.

Example agent prompts

"Determine the emotional tone and sentiment of text"
"Analyze sentiment of multiple texts at once (up to 20)"

Payment

Protocol: x402 -- HTTP-native pay-per-call, no signup, no API key
Network: Base L2 (eip155:8453)
Asset: USDC
Facilitator: Coinbase CDP (primary), PayAI (fallback)
Also reachable via ATXP (OAuth-wrapped x402, RFC 9728 protected-resource metadata)

Part of klymax402

100 x402 micropayment APIs for AI agents -- one wallet, USDC on Base, zero signup.

Catalog: https://klymax402.com/llms.txt
Full API reference: https://klymax402.com/llms-full.txt
Live stats: https://klymax402.com/stats

License

MIT

Sentiment Analyzer API