The api-client cheat sheet: every config option and method in one place

Everything else in this series explains why a feature works the way it does. This post skips the why — it’s the reference I actually want open in a second tab while I’m writing config, not something meant to be read top-to-bottom. Each section links conceptually back to the post that covers the reasoning, if you need it.

createClient(config)

defineModule({ config, methods })

Module-level config accepts the same keys as createClient’s baseURL, timeout, headers, auth, cache, retry, tenancy, validation — overriding the global value for every method in that module. See Part 3 and Part 4 for the merge order.

defineModule({
  config: { timeout: 20_000 },
  methods: {
    methodName: async (ctx, ...args) => ctx.request({ /* spec */ }),
  },
})

ctx.request(spec, perCall?)

spec:

perCall (PerCallConfig):

Returns ApiResponse<T>:

{ data: T, status: number, statusText?: string, headers: Record<string, string>, fromCache?: boolean }

See Part 3.

Error classes

Cache methods

ctx.cache.invalidate(key: string): Promise<void>
ctx.cache.invalidatePattern(pattern: string): Promise<void>

See Part 6.

Events (api.on(event, handler))

Codegen CLI commands

RPC bridge

// server
createRpcHandler(realClient, { expose: { moduleName: ['methodName'] } })

// browser
createRpcClient({ endpoint: '/api/rpc' })

Deny-by-default: only { module, method } pairs listed in expose are reachable. See Parts 14–15 for the full architecture and security model.

TanStack Query integration

useApiQuery(api.module.method, [args])
useApiMutation(api.module.method, { invalidates: [api.otherModule.otherMethod] })

Available for React, Vue, and Solid, with identical key-generation semantics. See Part 13.

Testing

createMockClient({
  moduleName: { methodName: async (...args) => mockReturnValue },
})

See Part 17.

What this post is for

Not a takeaway section this time — this whole post is the takeaway from the series so far, compressed. If a row here doesn’t make sense on its own, that’s exactly what the linked post is for.

Next: troubleshooting and FAQ — the errors I’ve actually hit using this package, told as the debugging stories they actually were.

• developerehsan