Core concepts

Understand the application graph, validated functions, runtime contracts, invocation context, and environment before adding capabilities.

Use these pages to understand the code you’ve written in the Orders tutorial. Start with functions and schemas, then explore how RELKIT connects the application. Development, tests, HTTP, events, jobs, the Inspector, generated clients, and deployment all consume that graph instead of maintaining separate descriptions of the application.

Learn the model in order

Start with the application model and functions. Schemas define values crossing a boundary; declared errors define expected failures. Context grants one invocation access to its approved capabilities, while the environment contract resolves process configuration before handlers run.

One source, many consumers

The certified minimal starter keeps the root configuration intentionally small:

/** Declares backend defaults; inspection remains disabled unless explicitly enabled. */
import { defineApp } from "@relkit/app/config";
import env from "@app/platform/env.js";
// relkit:create:deployment-imports

export default defineApp({
  env,
  telemetry: { redaction: { mode: "development-redacted", maxBytes: 65_536 } },
  server: { port: 3000, maxBodyBytes: 1_048_576, apiDocs: { ui: "scalar" } },
  // relkit:create:deployment
});

Source files are the application. .relkit/generated and .relkit/build are derived artifacts; inspect them when diagnosing a problem, but repair the descriptor, configuration, or environment that produced them.

TypeScript descriptors → relkit check → application graph
                                      ↘ dev · tests · build · inspector · deployment

Check your understanding

From a generated application, run:

bun run check
bun run relkit graph print

check evaluates configuration, discovers descriptors, validates graph relationships, and refreshes generated contracts. graph print lets you inspect the resulting IDs and edges without starting the server or creating external resources.

Continue with Service after these concepts to organize behavior by domain and choose the public operations other domains and transports may call.