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Bulk Keyword Difficulty
 
This endpoint will provide you with the Keyword Difficulty metric for a maximum of 1,000 keywords in one API request. Keyword Difficulty stands for the relative difficulty of ranking in the first top-10 organic results for the related keyword. Keyword Difficulty in DataForSEO API responses indicates the chance of getting in top-10 organic results for a keyword on a logarithmic scale from 0 to 100.  
You can learn more about how we calculate this metric in this help center article.