APIs

gRPC and Protobuf: free-recall review

Crux Free-recall prompts across the gRPC/Protobuf unit — wire format, field-number discipline, compatibility, streaming, deadlines, and the edge decision. Answer first, then reveal.

Your altitude — climbing toward senior

ZeroJuniorMiddleSenior

You are at senior altitude — in orbit

◷ 13 min

Retrieval beats re-reading. For each prompt, say or write a full answer from memory before you open the model answer — the effort of recall is what makes the field-number contract and the streaming shapes stick.

Goal

Reconstruct the unit’s spine — why the wire carries numbers not names, what makes a schema change safe, the four call shapes, how deadlines propagate, and where gRPC belongs versus REST — without looking back.

Recall before you leave

01
What exactly does Protobuf put on the wire, and what does that buy and cost versus JSON?
02
Why is renaming a field free but renumbering or reusing a field number a production disaster?
03
Explain backward and forward compatibility in Protobuf and the two mechanisms that provide them.
04
Name the four gRPC call shapes and the deciding question for picking one.
05
How do gRPC deadlines work, and what is the classic confusing failure they cause?
06
When does gRPC win over REST/JSON, and why can't the browser speak it directly?

Recap

If you could reconstruct each answer from memory, you hold the unit’s spine: the wire carries field numbers and values, never names, which is why renaming is free and renumbering is corruption; add-only evolution with reserved gives two-way backward/forward compatibility; the four call shapes are chosen by who streams; deadlines propagate and can fail a caller whose work actually landed, so idempotency is the fix; and gRPC belongs between your services while REST/JSON or Connect-RPC stays at the browser edge.

Continue the climb ↑gRPC and Protobuf: schema and proto reading