Some NCBI API services limit number of requests per second (rps). The 3 rps baseline is adequate for most applications and users. The 10 rps ceiling via NCBI sign-up allows for enhanced data access, while also minimizing the risk of resource outages due to excessive service calls or requests from any single access node or user cohort. If you require a higher rate limit for your API key, please write to info@ncbi.nlm.nih.gov including documentation of the reasons for such enhanced access. NCBI may then grant a higher rate limit for your existing API key. At present, API keys authorizing request rates exceeding 10 rps are designed specifically for Entrez Programming Utilities (E-utilities or EUtils), so users with such enhanced keys should continue to limit requests to Datasets and dbGaP to a maximum of 10 rps. Although the enhanced keys will still interface with non-EUtils applications, intensive usage beyond the 10 rps threshold for them may result in reduced user access at the discretion of these services.