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fastapi.online — Word Definition Lookup
x402
fastapi.online — Word Definition Lookup is a paid API for AI agents from api.fastapi.online, paid per call via x402, $0.0005/call, status unknown (last checked 2026-09-15).
Returns a definition for a given word, optionally contextualized by a provided context string, using self-hosted AI inference.
Price / call$0.0005
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
A natural-language definition of the submitted word, potentially shaped by the optional context provided, generated by a self-hosted AI inference model.
Example use cases
Vocabulary help while reading
“I just came across the word 'apostasy' in an article about religion — what does it mean in that context?”
Technical term clarification
“Can you define the word 'idempotent' for me? The context is software engineering and API design.”
Writing assistance for precise word choice
“What does 'laconic' mean? I'm writing a formal essay and want to make sure I'm using it correctly.”
Technical details
Endpoint
POSThttps://api.fastapi.online/define-wordWhen to prefer
Choose this endpoint when you need a quick, AI-generated word definition without requiring a dictionary API account or signup. Particularly useful when context-aware definitions are needed (e.g., domain-specific meanings), and when crypto micropayment per-call billing is preferred over subscription pricing. Ideal for agents needing lightweight, on-demand vocabulary lookups.
Side effects
- Word field is empty or missing — validation error returned
- Word exceeds 100-character limit — request rejected
- Context exceeds 500-character limit — request rejected
- Ambiguous or nonsense input word — model may return a best-effort or fallback definition
- Payment not included or insufficient — 402 Payment Required response
- Model inference timeout or service unavailability — 5xx error
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| word | string | |
| context | string |
Tags
x402
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