Spring: @Valid triggers Bean Validation on a request body

Without @Valid the constraints on your DTO are ignored and invalid data reaches your service.

Code

record OrderRequest(
        @NotBlank String sku,
        @Min(1) int qty,
        @Email String contact) { }

@PostMapping("/orders")
Order create(@Valid @RequestBody OrderRequest body) { ... }

Output

POST with qty = 0 returns:
400 Bad Request
{"errors":[{"field":"qty","message":"must be greater than or equal to 1"}]}

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Published 2026-08-11