Programming Fundamentals

How do I validate untrusted input at the boundary?

Write a validator that rejects malformed, wrong-type, out-of-range, and hostile input at the boundary — and explain what belongs at the client, server, and database.

how the lesson trains it — the Sage loop

This is the preview. The lesson is the rep.

In the full lesson (~75 minutes) you work the loop on a real scenario and leave with evidence in your ledger — not a completion checkmark.

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keep pulling the thread

How do I write and run my first program?→What is a variable in programming and how do I use one?→What is the difference between numbers and strings in Python?→How do I read user input in Python and convert it to a number?→

Programming Fundamentals

How do I validate untrusted input at the boundary?

Write a validator that rejects malformed, wrong-type, out-of-range, and hostile input at the boundary — and explain what belongs at the client, server, and database.

how the lesson trains it — the Sage loop

This is the preview. The lesson is the rep.

In the full lesson (~75 minutes) you work the loop on a real scenario and leave with evidence in your ledger — not a completion checkmark.

Start this course Explore the academy

keep pulling the thread

How do I validate untrusted input at the boundary?

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How do I validate untrusted input at the boundary?