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Tutorial 08 · Basic logic

Cross-field validation

Compare two answers and show a useful error when they disagree. This example confirms an email address.

Step-by-step guideSetup · Flow · Test

1. Prepare the survey

Open a practice survey from Home and click Edit. Add these pages and questions in the order shown. Click a question type in the builder palette, then select the question to edit its label and choices. Use Add Page for later pages.

PageQuestionType and setup
Confirm your emailEmailEmail · Optional initially
Confirm your emailConfirm emailEmail · Optional initially

2. Configure the logic

  1. Choose validation

    Choose Validate an answer. In When, select Email and set Condition to is not empty. Click Next.

  2. Choose what to validate

    Set Action to Validate answer, select Confirm email, and enter Enter the same email address in both fields. in Message.

  3. Compare the answers

    Inside the validation condition, select Confirm email, set Condition to equals, and set Compare with to Another answer. In Answer, select Email. This check must pass when the outer condition matches.

  4. Review the two layers

    Click Next. The outer rule decides when validation runs; the action checks that the confirmation equals the original. Give the rule a clear name such as Emails must match.

In the app. Configure the condition that triggers cross-field validation.Click the screenshot to enlarge it. Press Escape to close.
In the app. Choose the action, its target and any Otherwise behaviour.Click the screenshot to enlarge it. Press Escape to close.

3. Review the logic flow

Read the final flow before saving. For conditional rules, YES means the condition matches and NO means it does not. An unanswered source can leave the rule waiting. Use Try answers when it is available, or Back to adjust the setup. View full survey flow provides the surrounding page order and saved rules.

In the app. The final flow review for cross-field validation, before Save logic.Click the screenshot to enlarge it. Press Escape to close.

4. Save and publish

  1. Save the reviewed logic

    On the final wizard step, click Save logic. Your changes join the survey draft. If the tutorial creates more than one rule or setting, complete and save every part before publishing.

  2. Confirm the draft is saved

    Close Logic. Wait for the builder’s save/sync status to complete. You can reopen Logic to check the saved rule or setting. Save logic does not by itself update the public survey.

  3. Publish the survey

    Click Publish in the builder, then Publish Now in the confirmation. Use the public link to test the published survey. After later edits, publish again before checking the live result.

  4. Test in a fresh respondent tab

    Start with a fresh public survey tab. If you already had an older published version open, reload and start a new response. Use a practice survey for test submissions.

5. Test the respondent experience

Run both the matching and alternative cases. Change answers and revisit earlier pages where the test asks you to, rather than testing only one path.

Try thisExpected result
Different addressesSubmit is blocked with the custom error next to the confirmation field.
Matching valid addressesValidation passes.
Email is unansweredThe conditional comparison waits. If both fields must always be answered, also mark them required.
In the app. Different email addresses show the custom confirmation error.Click the screenshot to enlarge it. Press Escape to close.

Common mistakes and useful limits

  • Do not type a question name into a fixed value. Choose Another answer and select the actual source question.
  • Use two Email questions; a text box does not provide the same email-format check.
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