SpacetimeDB

Licensing and Pricing Model

• Uses a BSL-style license with limits (e.g., effectively one instance per service; broader features in the hosted offering).
• Some are wary of the delayed-open license and would prefer more permissive alternatives.
• “Maincloud” / “Energy” credit billing feels crypto-ish or needlessly abstract to several; comparisons made to Snowflake/Vercel units.
• Bandwidth pricing (~$0.28/GB) is called out as high, especially at scale; request for flat-rate options and fear of accidental large bills.
• Team says prices are conservative and intended to be lowered later.

Core Architecture and Goals

• In-memory relational DB with WASM “reducers” (stored procedures) meant to host all game/server logic.
• Promises: automatic client–server sync, elimination of server–DB sync layer, and simple deployment (upload WASM to the DB).
• Compared to “server in the DB” systems like Convex, and to in-memory SQLite plus a networking layer.
• Seen as a “universe brain reorg”: powerful if you fully buy into the new mental model, but requires rethinking architecture.

Scalability and Clustering Concerns

• Marketing claims very low latency and high throughput; commenters ask for concrete benchmarks and cluster design details.
• Internally, they say each DB is an actor in an Erlang/Elixir-style distributed system with inter-module communication; that piece isn’t yet public.
• Some argue that real MMO scaling is more about sharding, geography, and what you trust the client with than about raw DB speed.

Fit for Game Development and Netcode

• Many multiplayer devs say main challenges are lag masking, prediction, rollback, and cheat resistance, not CRUD or persistence.
• Current product doesn’t natively solve those; team plans future automatic client-side prediction by re-running server WASM on clients and reconciling.
• Skeptics note this is still a “TODO” without shipped examples; optimists see value even if lag masking remains app-specific.
• Several worry you’d need to significantly restructure servers, and possibly reimplement physics/pathfinding/animation outside Unity/Unreal, to fit the model.

Physics and Simulation in the DB

• Docs show very naive collision checks and assert “DB is fast” without numbers; physics/netcode specialists are unconvinced.
• Community experiments embed a Rust physics engine (Rapier) into WASM, then write results back into tables; interesting but early.
• Open question whether serious networked physics and engine integration are practical within this paradigm.

Developer Experience and Adoption

• Mixed feelings on tying schema directly to language structs/annotations (ORM-style) vs explicit SQL.
• Some report building small MMOs quickly and like the live query / push-based model.
• Others see significant risk in adopting a young, unconventional stack from a team whose flagship MMO isn’t yet released, citing past MMO backend hype that fizzled.