gRPC documentation is thorough on the protocol’s features and sparse on the operational realities of running it at production scale. The gap between the getting-started experience and the production experience is wide enough to have surprised most of the teams that have made the journey. The surprises are not fatal. They are the kind that would have been useful to know before the architecture decision was made.

The gRPC pitch is compelling: Protocol Buffers serialization that is faster and smaller than JSON, HTTP/2 multiplexing that reduces connection overhead, generated client and server stubs that eliminate serialization bugs, strong typing that catches integration errors at compile time rather than runtime. All of these benefits are real. All of them come with operational requirements that the pitch does not emphasize.

Internal APIs — interfaces between services within an organization’s own systems — receive less design attention than public APIs because they lack the external consumer accountability that forces quality. The teams that consume internal APIs are colleagues, not customers. Breaking changes can be coordinated by Slack message rather than deprecation notice. Documentation is optional when the API author sits nearby.

The organizations that operate this way accumulate a specific kind of technical debt: internal integrations that are brittle, undocumented, and implicitly coupled to implementation details that were never meant to be part of the interface. The cost of this debt is the engineering time spent maintaining integrations that should be stable, debugging failures caused by undocumented behavior changes, and slowing down service evolution because teams are afraid to change APIs that other teams depend on in ways nobody has mapped.