is-email-hosted-by-microsoft-365-bulk

Choose this endpoint when you have a list of 2–20 domains and need Microsoft 365 hosting status for all of them in a single call. It processes domains concurrently and returns results in input order, making it far more efficient than looping the single-domain endpoint. Prefer this over the single endpoint whenever batch throughput or cost-per-domain matters, and over the watch endpoint when you need an immediate one-shot answer rather than ongoing change monitoring.

• Domain unreachable or DNS lookup fails — item-level error field populated, counted in failure total
• Batch exceeds 20 domains — request rejected or truncated
• Network timeout during concurrent DNS resolution — partial results with errors on affected items
• Malformed domain string in input — per-item error returned for that entry
• Payment not received or x402 authorization fails — entire batch call rejected