How logic works

Every Flex Forms rule is one sentence: When something is true about an answer → Then do something. In Studio you author that sentence in two complementary surfaces — not three competing entry points.

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Decision guide — where should this live?

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Branch (fast path)

On a choice question, open Branch from the field chrome workflow icon (not by selecting the field alone). For each option:

1. Show follow-up — pick field(s) to reveal (complementary hide is compiled automatically).
2. Go to page — jump destination.
3. Otherwise — default path when no option row matched (continue to next page, or jump elsewhere).

On a non-choice field (text, number, …), use the same chrome icon (Show if…) to pick a source field + operator + value — Studio compiles a Show rule for that target (inverted attachment). Switch to full When → Then with Edit as When → Then when you need more than a single show condition. When a field already has advanced Rules Studio cannot represent as simple Branch rows, Branch shows a note with Open Rules. Details: Field conditions / Branch.

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Rules · Flow · Simulator

Open Workflow from the Studio center top bar (or ⌘/Ctrl+Shift+L). Inside the hub: Flow health sits on the right of the Workflow header (conflict count + tooltip). Critical issues — jump cycles, incomplete jump targets, unreachable non-terminals, no reachable terminal — block Publish. Warnings (unreachable terminals that Fill cannot reach, dual-write calculate/set_value, …) require an explicit acknowledge before Publish continues. Pages reached only by linear Next from a non-terminal page (typical quiz spine) are normal and do not warn on Publish. The Flow map may still outline pages without an inbound jump for editing clarity — that outline alone is not a publish gate. Full walkthrough: The Logic Board.

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Anatomy of a rule (When → Then)

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When (conditions)

1. Pick a source field (what the respondent answered).
2. Pick an operator (equals, contains, is empty, equals set, …).
3. Pick a value — type a literal, use a choice chip, or pick another input field (live compare).
4. Combine clauses with All (AND) or Any (OR). Nest groups for (A AND B) OR C.

Studio only shows operators that fit the field type.

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Then (actions)

Stack one or more actions: Show / Hide, Require / Optional, Disable / Enable, Set / Clear value, Jump to page, Calculate, Hide submit.

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First rule in Studio (5 minutes)

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Evaluation order (who wins)

On every answer change, fill recomputes on the server (Livewire):

1. Rules in evaluation order (form-level and field-anchored), top → bottom
2. Calculated Always → Calculate rules in canvas order
3. Hidden fields forced not required
4. Hidden answers cleared so stale data never submits

If two matching rules fight over the same target, the later matching rule wins. Conflict chips flag Show ↔ Hide fights — treat them as release blockers.

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Path validation & terminal pages

Multi-page forms track the visited path. Submit validates required fields on pages the respondent actually reached — not every page in the form. Mark terminal pages (submit steps) so Map / flow health know where paths should end. Critical health issues block Publish until fixed. Warnings (unreachable terminal pages Fill cannot reach — for example a Fail page after a terminal Pass with no jump to Fail — plus calculate / set-value dual-writes) appear in the Logic health strip. They do not hard-block Publish by themselves, but Studio requires an explicit acknowledge (confirm) before Publish continues when warnings are present. Criticals must be fixed first. Linear multi-step pages after a non-terminal page do not trigger a Publish confirm.

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Cascade scrub (delete safety)

When you delete a field, page, or choice option, Studio automatically cleans logic that referenced it (When clauses, Then targets, jump page ids). You get a success toast with how many references were scrubbed (for example “Cleaned 3 logic reference(s) after the change.”). If nothing referenced the deleted item, Studio stays quiet — no orphan jumps left behind.

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Blank answers (the #1 source of “my rule never fires”)

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Compare to another answer

In the Value control, type a fixed value or pick an input field. The clause compares the source field to whatever the respondent typed in that other field (live). If the referenced field is blank, operators that need a value fail-closed (clause false).

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Calculated vs Calculate action

Tokens use {blockId} — pick fields from Value / Formula inserter. Blank number tokens make the whole numeric result empty. Details: Calculated fields · Calculate action.

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Troubleshooting checklist

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Deep dives