Validation

Validation isn't an afterthought in Axeom—it's part of the Blueprint. Axeom provides a native, zero-dependency validation engine through the s utility, while remaining completely flexible: you can use s, Zod, TypeBox, or any other library of your choice.

The Native s Validator

Axeom's built-in s utility is an ultra-lightweight validation engine designed specifically for the framework. It provides a familiar, chainable API with zero external dependencies, keeping your bundle size practically non-existent.

const CreateUserSchema = s.object({
  username: s.string().min(3),
  email: s.string().email(),
  age: s.number().optional()
});

app.post("/users", (ctx) => {
  // Direct access to validated body!
  const { username, email } = ctx.body;
  
  return { id: 1, username };
}, { 
  body: CreateUserSchema 
});

Bring Your Own Library

Axeom is library-agnostic. Because the engine relies on a simple Validator interface, you can use any library that provides a .parse() or equivalent method.

app.post("/external", (ctx) => {
  return ctx.body;
}, {
  body: z.object({
    external_id: z.string()
  })
});

Validating Other Segments

Axeom's validation covers every part of the request. Once validated, the data is automatically parsed and available on the context with full type safety.

app.get("/search", (ctx) => {
  const { q, page } = ctx.query;
  return { results: [], page };
}, {
  query: s.object({
    q: s.string(),
    page: s.number().default(1)
  })
});

Error Handling

When validation fails, Axeom interrupts the request and returns a 400 Bad Request with a clear description of the failure.