What two API protocols does Qdrant expose, and when would you choose REST versus gRPC?

Qdrant exposes both REST and gRPC APIs. REST is usually the easiest starting point because HTTP requests are simple to inspect with browsers, curl, API clients, and standard observability tooling.

gRPC uses Protocol Buffers and a binary transport, and it can be preferable for service-to-service workloads where lower protocol overhead, streaming capabilities, or high-throughput typed clients matter. The practical latency difference depends on the workload, network, payload size, and client implementation, so I would benchmark rather than assume gRPC is always faster.

The trade-off is debugging and ecosystem simplicity versus transport efficiency and strongly typed service integration. I often start with REST for administration or simple application paths and use gRPC when profiling shows transport overhead matters.

One misconception is that switching from REST to gRPC automatically fixes vector-search latency. If HNSW traversal, filtering, disk I/O, or embedding generation dominates the request, changing the API protocol may have little effect.