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Flask Academy · Lesson

Validate Required Fields by Hand

Reject empty or malformed input early.

Why Validate at All

Never trust raw input. Validation catches missing or junk data before it reaches your database or breaks your logic. 🛡️

Read the Field First

Pull each value with .get so an absent field gives None instead of crashing the view before you can check it.

email = request.form.get("email")

All lessons in this course

  1. Build an HTML Form That Posts
  2. Read and Default Query Parameters
  3. Validate Required Fields by Hand
  4. Redirect After Post (PRG Pattern)
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