Read the template in 10 minutes

The golden path: one mint, traced

1 · packages/node/grammar.ts — 7 lines

Every input the app understands. The template ships two, both from builtin grammars:

export const grammar = {
  "transfer-assets": builtinGrammars.evmErc721,        // {to, from, tokenId, isBurn}
  "midnightContractState": builtinGrammars.midnightGeneric,
} as const satisfies GrammarDefinition;

2 · packages/node/config.dev.ts — the wiring

Three nested builders, always in the same order:

• networks — an NTP clock (the main timeline), Hardhat, and Midnight;
• sync protocols — NTP as main, the two chains as parallel;
• primitives — an ERC-721 watcher (prefix transfer-assets) and a Midnight contract-state watcher (prefix midnightContractState). The prefix is the routing key into the grammar.

3 · packages/node/state-machine.ts — the logic

One stm.addStateTransition(kind, function* (data) {...}) per grammar key. The data object carries parsedInput (typed by the grammar!), blockHeight, signerAddress, and randomGenerator — remember that last one. DB writes go through yield* World.resolve(query, params).

4 · packages/node/api.ts — read-only REST

A Fastify router with direct SQL reads. State changes NEVER come through here — they only come from chains.

5 · packages/database/ — migrations + typed queries

migrations/*.sql create tables (applied by the sync node at startup); sql/*.sql holds named queries that bun run build:pgtypes compiles into typed TypeScript (*.queries.ts) — those are the objects the STM resolves.

6 · packages/batcher/ — the gasless mailbox

Everything above is reading chains. The batcher is how users write without paying gas: it's a small HTTP service (:3334) that accepts signed inputs at POST /send-input, verifies each signature, collects inputs for a time window (1 s in dev), and submits the whole batch as one transaction to the EffectstreamL2 contract — the batcher's wallet pays, and the sync node re-verifies every inner signature when the batch arrives, so the batcher can't forge anyone's moves.

Two things to spot in batcher.dev.ts:

• adapters — where batches can land. This template has two: paimaL2 (the EVM contract; the default target — our game moves go here) and midnight (balances/submits Midnight transactions).
• namespace — the security string users sign into every message. It must match the node's setSecurityNamespace(), or inputs get silently dropped — we'll set it in Step 4.

What we'll touch in Section C