Validaciones server-side para entradas criticas

[Kalebtron1]

Why this matters

Rejecting malformed input early keeps the scoring and lending flow safer.

Problem

The API currently depends too much on caller correctness for critical inputs.

Scope

• Validate request payloads at the API boundary.
• Return clear 4xx responses for invalid or incomplete requests.
• Keep the validation rules aligned with the flow docs.

Implementation guidance

• Work in api/calculate-score.js, api/evaluate-and-mint.js, api/get-available-credit.js, and api/get-user-data.js.
• Use explicit validation so invalid payloads fail fast.
• Keep the error messages easy to understand for contributors and reviewers.

Out of scope

• Changing the core business logic of the score or lending flows.
• Adding a new auth system.

Acceptance criteria

• PR includes validation logic in the listed endpoints.
• Reviewer can reproduce at least one invalid request and see the expected 4xx response.
• The PR description lists the accepted request shape and error cases.

Validation

• Run npm run dev and trigger an invalid request.
• Run npm run build before opening the PR.
• Confirm the endpoint rejects the malformed input with the expected status.

PR requirements

• Include Closes #43.
• Describe which invalid inputs are rejected.
• Note any shared validation helper that was introduced.

Complexity

• Medium (100 points)

[Oby38]

@Oby38 has applied to work on this issue as part of the Stellar Wave Program's 5th wave.

I'm interested in tackling this task. I enjoy debugging complex logic and have the exact engineering experience needed to fix the root cause of this error efficiently.

ℹ️ Repo Maintainers: To accept this application, review their application or assign @Oby38 to this issue.

[drips-wave]

Congratulations, @Oby38! 🎉 Your application was accepted by the repo's maintainers, and the issue is due on June 2, 2026.

🧑‍💻 @Oby38: Please resolve the issue such that the repo's maintainers have enough time to review your contribution before the due date. You'll earn Points for completing the issue on-time, which will make you eligible for a share of the Stellar Wave Program's reward pool.

Warning

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[drips-wave]

This issue has been completed by @Oby38 as part of the Stellar Wave Program's 5th Wave 🥳

😎 @Oby38: You earned 150 Points for completing this issue! After the current Wave ends, you'll be eligible for a percentage of the Wave's reward pool based on the percentage of total points you've earned. Learn more here. You can also Leave a review to share your experience working on this issue.

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