The ClickHouse database supports over 70 input formats out of the box, but selecting the most efficient format can be overwhelming. To answer this question, a benchmark called FastFormats was developed to measure server-side ingestion speed and hardware efficiency across different input formats. The results show that Native is the fastest and most efficient format, followed by ZSTD for compression. Pre-sorting has a moderate impact, while batching significantly improves efficiency. ClickHouse clients optimize inserts by selecting formats suited to their typical use cases, with those designed for high-throughput inserts automatically choosing Native. The HTTP interface provides greater flexibility than the native interface but lacks some advanced features. The support matrix shows that the C++ and Go clients currently support the native interface, while all main language clients except C++ support the HTTP interface.