At present, we support a flavor of JSON-RPC as one of the primary ways of integrating with a running node.

From discussions with users (e.g. @hdevalence), it's clear there's a need for a full gRPC interface to a node. This would dramatically simplify client generation for interaction with a node, and would help get around our very odd (inherited) JSON serialization quirks.

There's some context provided by ADR-057, but no clear decision was documented in that ADR. Previously, the team had decided to deprecate and remove gRPC support (see tendermint/tendermint#7121 and tendermint/tendermint#9683), but that decision has now been reversed.

Definition of Done

There are several deliverables associated with this issue, after which it could be considered done:

• Remove the existing gRPC broadcast API #650
• docs: ADR-106: gRPC API #850
• feat: Implementation of the versioned gRPC API as specified in the ADR-106 #2693
  • After it's on main, we can consider whether we should backport this to older releases.

Original issue: tendermint/tendermint#9751