Flow Step Types

Flows are built from a sequence of steps. Each step performs a specific action -- sending an email, waiting, checking a condition, or updating contact data. Steps execute in order for each contact that enters the flow.

Send Email

The most common step type. It renders a template with the contact's data and sends the email.

How It Works

Synapse loads the email template you selected.
All NLT expressions in the template are resolved using the contact's profile and the trigger event's attributes.
If any required variable is missing, the email is suppressed (not sent) and logged as "suppressed" instead of "failed".
If everything resolves successfully, the email is sent via your configured sender domain.
An email log entry is created to track delivery, opens, and clicks.

Configuration

Setting	Description
Template	Select the email template to send
Description	Optional note explaining the purpose of this step

Tip

You can reuse the same template across multiple flows. If you update the template, all flows using it will pick up the changes on the next send.

Wait

Pauses the flow for a specified duration before continuing to the next step. This is essential for building multi-step journeys like follow-ups and reminders.

How It Works

When the flow reaches a wait step, a timer is set for that contact.
The contact's trip status remains "active" during the wait.
After the delay expires, the flow resumes with the next step.

Configuration

Setting	Description	Examples
Duration	How long to wait	`1h` (1 hour), `24h` (1 day), `7d` (7 days), `2w` (2 weeks)

Common Patterns

Pattern	Duration	Use Case
Quick follow-up	`1h`	Nudge after form start but no submission
Next-day reminder	`24h`	Remind to complete a pending action
Weekly digest	`7d` or `1w`	Wait a week before sending a summary
Cooldown period	`48h`	Space out messages to avoid overwhelming contacts

Note

Wait durations support hours (h), days (d), and weeks (w). For example: 1h, 24h, 7d, 2w. There is no maximum duration enforced by the system, but very long waits may result in stale data by the time the flow resumes.

Condition

Branches the flow based on a check. This lets you create different paths depending on contact data, event history, or other criteria.

How It Works

Synapse evaluates the condition you define.
If the condition is true, one action is taken (continue or skip to end).
If the condition is false, a different action is taken.

Configuration

Setting	Description
Check	What to evaluate (see check types below)
If True	What to do if the condition passes (continue to next step, or skip to end)
If False	What to do if the condition fails (continue to next step, or skip to end)

Check Types

Check	Description	Example
Event exists	Has the contact performed a specific event since entering the flow?	"Has the contact submitted a `claim_completed` event?"
Contact property	Check a value on the contact's profile	"Is the contact's subscription status `subscribed`?"
Event attribute	Check data from the trigger event	"Is the trigger event's `claim_type` equal to `work_injury`?"

Example: Follow-Up Only If Not Completed

A common pattern is to send a reminder only if the contact hasn't taken the next action:

Step	Type	Details
1	Send Email	"Please complete your submission"
2	Wait	24 hours
3	Condition	Has the contact performed `form_submitted`? If yes: skip to end. If no: continue.
4	Send Email	"Reminder: you still need to complete your submission"

Update Contact

Modifies properties on the contact's profile. This is useful for tagging contacts based on their flow participation or updating their status.

How It Works

Synapse updates the specified properties on the contact's record.
These changes persist and are visible in the Contacts section.
Updated properties can be used by subsequent flow steps, other flows, and segment evaluations.

Configuration

Setting	Description	Example
Property	The contact field to update	`properties.onboarding_status`
Value	The new value to set	`completed`

Common Uses

Mark a contact as onboarded after they complete a welcome flow
Set a last_campaign property to track which flow the contact went through
Update a segment_tag property used by segments for future targeting

Note

Update Contact changes are applied immediately and are visible to all subsequent steps in the flow, as well as other flows and segments.

Conditional Split

Branches the flow into multiple paths based on contact attributes, event data, or property values. Unlike the basic Condition step (which has only true/false), a Conditional Split can have many branches -- each with its own condition and sequence of steps.

How It Works

Each branch defines a condition (e.g., "contact's country is SG", "plan is premium").
Synapse evaluates branches in order, from top to bottom.
The contact enters the first branch whose condition is true.
If no branch condition matches, the contact enters a default "Everyone Else" path (if configured) or continues to the next step.

Configuration

Setting	Description
Branches	An ordered list of conditions, each with its own label and filter criteria
Label	A human-readable name for each branch (e.g., "Premium Users", "SG Region")

Example: Region-Based Content

Branch	Condition	Action
Branch 1	`properties.country` is `SG`	Send "Singapore Welcome" email
Branch 2	`properties.country` is `US`	Send "US Welcome" email
Everyone Else	(no condition)	Send "Global Welcome" email

Note

Branch conditions are evaluated in order. If a contact matches multiple branches, only the first match is used. Order your branches from most specific to most general.

A/B Split

Randomly divides contacts into two or more groups based on percentages. Use this to test different email content, subject lines, or flow paths against each other.

How It Works

You define two or more variants, each with a percentage allocation.
When a contact reaches the A/B Split step, they are randomly assigned to one variant.
Each variant leads to a different path of subsequent steps.
Percentages must add up to 100%.

Configuration

Setting	Description
Variants	A list of variant names with percentage allocations

Example: Subject Line Test

Variant	Percentage	Action
Variant A	50%	Send "Don't miss this" email
Variant B	50%	Send "Limited time offer" email

Example: 3-Way Split

Variant	Percentage	Action
Control	33%	Send original email
Variant A	33%	Send new subject line
Variant B	34%	Send new design

Tip

Pair A/B Splits with Conversion Goals to measure which variant performs better. Set a goal event (like "purchase_completed") and compare conversion rates across variants.

Step Execution Order

Steps execute sequentially, from first to last. Each contact who enters the flow gets their own independent journey (called a "trip"). Key points:

Each trip progresses through steps one at a time.
If a step fails (e.g., email delivery error), it is logged and the trip continues to the next step.
Wait steps pause only that contact's trip -- other contacts in the same flow are unaffected.
Condition steps may cause a trip to skip remaining steps and end early.

Combining Steps

Here are some common flow patterns using multiple step types:

Welcome Series

Step	Type	Details
1	Send Email	Welcome email
2	Wait	3 days
3	Send Email	Getting started tips
4	Wait	7 days
5	Condition	Has user completed onboarding?
6	Send Email	Reminder to complete setup (only if not completed)

Transaction Follow-Up

Step	Type	Details
1	Send Email	Order confirmation
2	Update Contact	Set `last_order_date` to today

Conditional Notification

Step	Type	Details
1	Condition	Is contact's plan "premium"?
2	Send Email	Premium notification (if yes)

Tip

Start simple with one or two steps. You can always edit an active flow to add more steps -- new trips will use the updated flow, while existing trips continue with the version they entered on.

Looking for the API?

If you prefer to manage flow steps programmatically, see the Flows API Reference.