# Your AI shipped a backend that boots. That is the whole problem.

[Stack Overflow](https://yomu.fyi/company/stack-overflow) · Devlin Duldulao · Jun 23, 2026

**Type:** Problem & solution

## Summary

Backend security vulnerabilities often emerge from permissive default settings in web frameworks, a risk amplified when AI agents generate code focused solely on passing tests. Common failure points include unmetered request body parsing, unvalidated schemas, prototype pollution, and wildcard cross-origin resource sharing policies. To eliminate these foot-guns, the TypeScript framework DaloyJS enforces secure-by-default behavior across its entire routing and middleware model. It provides built-in request timeouts, streamed body size caps, prototype-stripping JSON revivers, and unified Zod schemas that simultaneously validate payloads and generate OpenAPI contracts. While secure defaults lower the risk of common infrastructure exploits, developers still remain responsible for application-level authorization and business logic correctness.

## Context

AI code generators and developers frequently ship backend APIs that boot and return successful responses on happy paths while unknowingly introducing vulnerabilities like unconstrained body buffering, SSRF, prototype pollution, and permissive CORS defaults.

## Approach / What changed

DaloyJS, a TypeScript web framework released at version 1.0.0-beta.0, implements secure-by-default principles by enforcing strict body limits, request timeouts, prototype sanitization, Zod-based request validation, and RFC 9457 error formatting out of the box.

## Takeaways

- Default configurations in standard Node.js Express setups frequently leave endpoints vulnerable to DoS from unmetered body parsing, SSRF, and prototype pollution without failing happy-path unit tests.
- DaloyJS enforces security defaults out of the box by checking Content-Length headers before buffering, stripping prototype keys during JSON parsing, and removing 5xx error details in production.
- Secure framework defaults protect against low-level infrastructure omissions but cannot prevent custom logic errors, such as broken object-level authorization or incorrect conditional assignments.

**Tags:** [Architecture](https://yomu.fyi/topic/architecture), [LLMs](https://yomu.fyi/topic/llm), [REST APIs](https://yomu.fyi/topic/rest-api), [TypeScript](https://yomu.fyi/topic/typescript)

[Read original post](https://stackoverflow.blog/2026/06/23/your-ai-shipped-a-backend-that-boots-that-is-the-whole-problem)