flow-designer

Flow Designer Patterns for ServiceNow

Flow Designer is the modern automation engine in ServiceNow, replacing legacy Workflows for new development.

Using the Flow Designer Tool

To create and manage flows programmatically, first discover the Flow Designer tool via tool_search({query: "flow designer"}). The discovered tool handles all GraphQL mutations for the full flow lifecycle.

CRITICAL — IF/ELSE/ELSEIF placement rules:

• Actions inside an IF branch: parent_ui_id = IF's uiUniqueIdentifier
• ELSE/ELSEIF blocks: must be at the same level as IF, NOT nested inside it
  • parent_ui_id = the same parent you used for the IF block
  • connected_to = IF's logicId (the sysId returned when creating the IF)
• Getting this wrong causes "Unsupported flowLogic type" errors when saving the flow

CRITICAL — TRY/CATCH placement rules:

When you add a TRY block, the CATCH companion is auto-created by the tool. TRY and CATCH are containers — actions go INSIDE them, not next to them.

• Actions inside TRY (steps that may fail):
  • parent_ui_id = TRY's uiUniqueIdentifier
  • order: 1, 2, 3, ... within the TRY
• Actions inside CATCH (error handling):
  • parent_ui_id = CATCH's uiUniqueIdentifier (returned as catch_ui_id from the TRY creation response)
  • order: 1, 2, 3, ... within the CATCH
• The next_order returned from creating the TRY/CATCH pair is for the next sibling after the pair, NOT for children inside them. Use it for the action after the try/catch, not for actions inside them.

Do NOT create flows via background scripts, GlideRecord, or REST calls to sys_hub_* tables. Always discover and use the Flow Designer tool via tool_search({query: "flow designer"}) — it handles the GraphQL mutations correctly. Background-script approaches will silently produce broken flows.

Flow Designer Components

Component	Purpose	Reusable
Flow	Main automation process	No
Subflow	Reusable flow logic	Yes
Action	Single operation (Script, REST, etc.)	Yes
Spoke	Collection of related actions	Yes