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fastapi.online Sentiment Intensity Analyzer
x402
fastapi.online Sentiment Intensity Analyzer is a paid API for AI agents from api.fastapi.online, paid per call via x402, $0.001/call, status unknown (last checked 2026-09-14).
Analyzes text and returns fine-grained sentiment intensity scores (positive, negative, neutral, compound) for the provided input.
Price / call$0.001
Success—
StatusUnknown
How this service works
Chat, embeddings, OCR, speech-to-text, image editing, image understanding (captioning/Q&A), text-to-speech, translation, writing tools, classification tools, developer tools, local utilities, format/checksum validators, encoding & crypto utilities, date/time calculators, geo/coordinate math, math & finance calculators, novelty tools, and business/social writing generators — 179 endpoints in all, across multiple specialized self-hosted models. Pay per call with crypto — no signup — or get an API key.
Output
Returns numeric sentiment intensity scores for the input text, typically including positive, negative, neutral, and compound scores — each in the range 0.0 to 1.0 (or -1.0 to 1.0 for compound), reflecting the intensity of each sentiment dimension detected in the text.
Example use cases
Customer review sentiment scoring
“Score the sentiment intensity of this Yelp review for me: 'Absolutely loved the food and atmosphere, but the wait time was brutal and the staff seemed disinterested.' Tell me how positive and negative it reads overall.”
Social media post tone analysis
“Analyze the emotional intensity of this tweet: 'Just got off the worst customer service call of my life. Three hours, zero resolution. Never buying from them again.' How negative is it?”
Support ticket triage by sentiment
“Check the sentiment intensity of this support message and tell me how urgent or negative it sounds: 'I've been waiting two weeks for my refund and nobody is responding to my emails. This is completely unacceptable.'”
Technical details
Endpoint
POSThttps://api.fastapi.online/sentiment-intensityWhen to prefer
Choose this endpoint when you need fine-grained, numeric sentiment intensity scores (including a compound score) rather than a simple positive/negative label. It is priced at $0.001 USDC per call with no signup required, making it ideal for lightweight, pay-per-call workflows or agents that need to score text at low cost without managing API keys. Prefer it over heavier NLP platforms when you only need sentiment intensity and want crypto-native, frictionless payments.
Side effects
- Empty or whitespace-only text returns a validation error (minLength: 1)
- Text exceeding 8000 characters is rejected (maxLength: 8000)
- Non-text or malformed input body returns a 400/422 error
- Payment not provided or insufficient USDC triggers a 402 Payment Required response
- Temporary service unavailability on self-hosted backend may cause 503 errors
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| text | string |
Tags
x402
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