The Dirty Truth About “Real-Time” Sync in Ecommerce and why i will fight you for it.

Everyone says their integration is real-time.

Very few actually are.

And in ecommerce, that lie quietly breaks your marketing.

If you’re using Klaviyo with a POS like Lightspeed, this matters more than you think. Because timing is the difference between relevance and noise.

Let’s talk about what “real-time” really means, why most integrations fake it, and why your flows feel late, flat, or broken even when nothing looks wrong.

What “Real-Time” Should Mean (But Usually Doesn’t)

In a perfect world, real-time sync means:

• A customer buys in-store

• Their data hits Klaviyo immediately

• Flows trigger while intent is still hot

• Segments update instantly

• Nothing is delayed, duplicated, or missed

That’s real-time.

What most platforms actually mean is:

“We check for updates every so often and hope that’s good enough.”

Hourly syncs. Batched jobs. Background processes. Quiet delays.

Not broken. Just slow.

And slow data is dangerous.

Why Delayed Sync Quietly Kills Performance

Let’s say a customer buys in your physical store at 2:07pm.

If your POS to Klaviyo sync runs hourly:

• Their profile updates at 3:00pm (best case)

• Or later if the queue is busy

• Or tomorrow if something hiccups

By then:

• They’ve already left the store

• The emotional peak is gone

• Your post-purchase email feels generic

• Your SMS feels late

• Your “real-time” flow fires when it no longer matters

Nothing breaks.
Everything underperforms.

That’s the worst kind of bug.

The Big Lie: “Close Enough” Timing

Native integrations love to say:

“Syncs automatically”

They rarely say:

“Syncs immediately”

Because immediate is expensive.
It requires:

• Event-based architecture

• Webhooks

• Error handling

• Retry logic

• Deduplication

• Observability

Most native integrations are built to check a box, not power lifecycle marketing at scale.

They’re designed for demos.
Not for agencies.
Not for multi-store retailers.
Not for serious automation.

Why Klaviyo Feels Broken (When It’s Not)

This is where people get it wrong.

Klaviyo isn’t the problem.

Klaviyo assumes:

• Events arrive on time

• Profiles are up to date

• Opt-outs are accurate

• Segments reflect reality

When data arrives late, Klaviyo does exactly what it’s told. It just acts on old information.

So you see:

• Flows triggering late

• Segments lagging behind reality

• Customers getting emails they shouldn’t

• Missed upsells and win-backs

Klaviyo looks guilty.
Your data pipeline is the real culprit.

POS Data Is Unforgiving

POS data is not like ecommerce data.

It’s messier.
It’s faster.
It’s human.

You’re dealing with:

• In-store purchases

• Staff-created customers

• Partial emails

• Phone numbers instead of emails

• Refunds, exchanges, split payments

• Multiple locations hitting the system at once

If your integration waits around to batch that data, things drift fast.

That’s why POS → Klaviyo sync is where “real-time” claims fall apart first.

What Actually Breaks When Sync Isn’t Real-Time

Here’s what we see break in the real world:

• Welcome flows firing after the second purchase

• Post-purchase emails landing the next day

• VIP segments lagging by hours

• Win-back flows triggering for customers who just bought

• Unsubscribed customers still marked as contactable in POS

• Duplicate profiles creeping in quietly

None of these throw errors.
They just leak money and trust.

What Real-Time Sync Actually Requires

True real-time sync isn’t marketing copy. It’s engineering.

It requires:

• Event-driven updates, not scheduled pulls

• Immediate pushes from POS to Klaviyo

• Smart deduplication at the profile level

• Two-way awareness of customer state

• Continuous monitoring so failures don’t go unnoticed

This is where most native integrations stop.
And where tools like Gather start.

Why Gather Treats “Real-Time” Seriously

Gather was built specifically because hourly syncs weren’t good enough.

Instead of polling on a schedule, Gather:

• Pushes customer and order data as events happen

• Updates Klaviyo profiles immediately

• Syncs opt-outs and preference changes back to POS

• Prevents duplicate profiles before they’re created

• Monitors sync health so failures don’t hide

The goal is simple:

When something happens in your store, Klaviyo knows about it now. Not later.

That’s how lifecycle marketing is supposed to work.

This Isn’t About Speed. It’s About Truth.

Real-time sync isn’t about being fast for the sake of it.

It’s about:

• Accurate segments

• Timely messaging

• Respecting customer intent

• Trusting your automations again

If your data is late, your marketing is lying to you.

And no amount of flow optimisation can fix that.

The Bottom Line

If your integration says “real-time”, ask:

• Is it event-based or scheduled?

• Does it push instantly or check periodically?

• Does it handle POS edge cases?

• Does it sync customer state both ways?

If you don’t know the answers, you’re probably not running real-time.

And if you’re using Lightspeed with Klaviyo, that gap shows up fast.

Fix the data layer, and Klaviyo suddenly feels powerful again.