Yahoo! JAPAN Proofreading Support API is a Japanese text proofreading endpoint from LY Corporation, available through the Yahoo! Developer Network. The API checks for character input errors, word misuse, unclear notation, and inappropriate expressions including offensive language and registered trademarks.
The service follows the JSON-RPC 2.0 specification with POST-only requests, making integration straightforward for developers building custom proofreading workflows. Responses include the flagged word, replacement suggestions, supplementary notes, the reason for the flag (conversion error, misuse, colloquial expression, etc.), and position information for precise text highlighting.
Many free Japanese proofreading tools rely on this API as their backend, demonstrating its reliability and the quality of Yahoo! JAPAN’s natural language processing. Developers can integrate the same technology into their own applications, content management systems, or automated text processing pipelines.