Crash Reporting for Nakama Backed Games

Nakama is an open source game server that you self host or run managed, giving you authoritative matches, realtime sockets, RPCs, and storage. Because it runs your server logic in a runtime, Nakama backed games crash on two fronts: your client can mishandle a socket message or RPC response, and your server side match handler can error while ticking match state. The two look unrelated from a single client crash report, yet they are often two ends of the same broken contract. Local testing against a fresh server with one client rarely exercises the match churn, presence changes, and RPC versioning that production hits. This post covers capturing the Nakama context that makes both kinds reproducible.

Client and server runtime as two crash surfaces

Nakama runs your authoritative match logic in its server runtime, written in Go, Lua, or TypeScript, and runs your gameplay client separately. A crash can originate in either, and they require completely different fixes. A client crash is in your engine process reading a Nakama response; a server runtime crash is in your match handler, surfacing to clients as a dropped match or an error message. The first context to capture is therefore which side failed, because a server runtime error reported by a confused client looks just like a client bug.

When the server runtime errors inside a match handler, the match can desync or terminate, and clients then crash trying to process the abnormal end. So a single client crash report can actually be the downstream symptom of a server side match handler exception. Capturing whether the client received an error or unexpected match state, alongside your server runtime logs keyed by match id, lets you connect the two. Without that linkage you fix the client symptom and the server bug keeps killing matches.

Match state, tick, and presence

Authoritative Nakama matches tick on the server and broadcast state to joined clients, and crashes cluster around presence changes: a player joins or leaves mid match and your match handler or client references a presence that is gone. Capturing the match id, the current tick, and the presence list size at crash time exposes these. A client that crashes processing match data for a player who just left is a presence handling bug, and the tick tells you how far into the match it happened.

Match state itself is a contract between server and client, and skew breaks it. If your server runtime broadcasts a state shape your client does not expect, because you updated one side, the client crashes deserializing it. This is the realtime equivalent of an RPC version mismatch. Recording the match id, the state opcode, and the client version at crash time reveals skew immediately, letting you see that crashes concentrate on one opcode and one client version rather than being a random realtime glitch.

Sockets, sessions, and reconnection

Nakama realtime uses a persistent socket authenticated by a session, and both the socket and the session have lifecycles that crash games when mishandled. A session token expires, the socket drops on a network change, or a reconnect leaves the client in a half joined match state. Code that assumes the socket is connected, or that the session is still valid, crashes during these transitions. Capturing the socket connection state and the session validity at crash time separates transition crashes from steady state logic bugs.

Reconnection is especially crash prone because rejoining a match mid flight requires reconciling client state with the authoritative server state, and any gap throws. A client that reconnects and tries to resume a match that already ended, or whose presence was removed during the disconnect, hits code paths normal play never reaches. Recording whether a reconnect was in progress and the time since the last socket message at crash time lets you identify these reconnection races, which are the dominant realtime crash category and nearly impossible to reproduce without that context.

RPC contracts and storage

Nakama RPCs call your server runtime functions and return a payload, and like CloudScript style backends they crash on version skew and unhandled errors. An RPC that returns a new field your old client ignores is fine, but a client expecting a field an old server does not return crashes. Capturing the RPC name and whether it returned an error or an unexpected shape, plus the client version, exposes contract mismatches between your deployed runtime and your shipped clients.

Storage adds a quieter crash source. Nakama storage is a key value store with versioning and permissions, and a client that reads a record that was never written, was written with a different schema, or fails a permission check crashes if it assumes success. Recording the storage collection and key being accessed, and whether the read succeeded, at crash time turns a per player storage crash into a concrete record you can inspect. As with player data elsewhere, these depend on individual account state and are otherwise hard to reproduce.

Setting it up with Bugnet

Bugnet captures Nakama client crashes with their full stack trace and device context, and the in game report button snapshots game state automatically, so a realtime failure arrives with the match the player was in. To make Nakama tractable, use custom fields to attach the session and user id, the match id and tick, whether the crash was client or runtime symptom, the RPC name, the socket state, and the storage key. Those fields convert an opaque client crash into a precise statement about which Nakama interaction failed, all in one dashboard you can cross reference with your server logs.

Bugnet folds duplicate reports into a single issue with an occurrence count, which fits Nakama crashes that recur across many matches and sessions. You can see that a reconnect crash hit 110 times, all with a stale match id after a socket drop, and recognize a reconnection race rather than a random glitch. Filtering by match opcode, RPC name, or client version confirms skew and verifies a fix, so you prioritize the Nakama interaction that is actually ending the most player matches and sessions.

A two sided Nakama crash workflow

Instrument both sides: add the session, match, RPC, and socket context to your client reporting, and key your server runtime logging by match id and user id so you can correlate a client crash with the server handler that caused it. The two sided view is what makes Nakama crashes tractable, because so many client symptoms are downstream of a runtime match handler error. Set this up once and every future crash arrives with both ends of the broken contract within reach.

Test match churn, presence changes, reconnection, and RPC version skew deliberately before each release, since those are where Nakama concentrates its crashes and single client tests never go. When grouped reports point at one opcode or one reconnect path, reproduce it by driving that exact match transition. Over releases your match handler error handling, presence reconciliation, and socket lifecycle code grow robust, and the diffuse Nakama crashes that come with self hosted realtime servers become a small, well understood set with clear causes on both sides.

A Nakama client crash is often a server match handler error in disguise. Capture the match id on both sides so you can connect the symptom to its cause.