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This page explains the mental model behind Flow Builder. Read it once, then build faster with fewer redesigns.

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Deterministic paths

A Flow is a directed graph. Each block does one thing, then continues along a connected output. The same inputs produce the same outputs. That makes Flows ideal for:
  • Compliance-sensitive scripts
  • Menus and FAQs with fixed answers
  • Qualification, booking, and checkout steps
  • Any process where every branch is known
When input does not match a branch, design an explicit fallback (condition else-path, Default Reply, or handoff). Do not assume the contact will type a perfect keyword.

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Contact context

Every run is tied to a Contact. As the Flow executes, it can:
  • Read system fields (first_name, phone, channel, …)
  • Read and write custom user fields
  • Apply or remove tags
  • Move cards in a Pipeline
Data written mid-Flow is available to later blocks in the same run and to future Flows, Agents, and broadcasts.

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Personalization

Insert contact data in messages with double curly braces:
If a field is empty, the placeholder may render blank — set defaults on the field or guard with a Condition before sending.

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Omnichannel vs channel-specific

Prefer Omnichannel message types when the same content should run on multiple channels. Use channel-specific blocks only when you need a capability that does not translate (for example, WhatsApp interactive lists or Messenger cards). Test each target channel. Media formats and button limits differ — see Messages and media and Limits.

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Draft vs published

Saving edits does not publish them. Always publish after a verified test.
Publishing swaps the live graph for contacts already inside the Flow. Plan breaking changes with a duplicate Flow and staged cutover.

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Modular design

Keep Flows small and purposeful. Use Go to Flow to chain a parent orchestrator into specialized child Flows (payment, FAQ, human handoff). This stays under the 250 blocks per Flow limit and keeps ownership clear.

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Escape hatches

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Next

Builder

Learn the canvas controls.

Collect data

Capture answers into custom fields and tags.