The realistic answer is near-zero downtime, not zero, and the difference is minutes of controlled order pause, not a weekend offline. At 500 orders a day you average about 21 orders an hour, so a short, rehearsed window is affordable if a delta sync catches every order placed during it. The site stays browsable throughout. What pauses briefly is order capture.
Below is why zero is not achievable, an hour-by-hour cutover sequence, the delta sync, DNS and rollback plan and the freeze window to target. Our Shopify migration service builds this runbook with you, and our subscription migration answer covers recurring-billing customers.
Why near-zero, not zero
Three things have to switch together.
- Orders must land in one system. Two live order streams create duplicates and inventory errors.
- The final data sync needs a consistent snapshot of inventory, customers and open orders.
- DNS and payment endpoints change, and caches take time to clear.
The cutover sequence, hour by hour
A template to adapt. Hours are relative to the start of cutover.
| Hour | Step | Owner |
| -24 to -2 | Content and catalogue freeze on the old store. Final rehearsal checks. | Agency and merchant |
| -2 | Lower DNS TTL in advance. Announce a short maintenance banner if needed. | Agency |
| 0 | Switch old store to read-only for orders, or enable a short checkout pause. | Agency |
| 0 to 1 | Run the final delta sync: new orders, customers, inventory, open carts. | Agency |
| 1 | Validate counts, inventory and a test order on the new store. | Both |
| 1 to 2 | Flip DNS and enable redirects. Open checkout on the new store. | Agency |
| 2 to 6 | Monitor orders, payments, fulfillment and errors. Keep old store ready. | Both |
| 6 to 72 | Day-one support, redirect checks, sitemap submission, rollback window. | Both |
This follows published migration runbooks and is a template. Your steps depend on ERP, payments and fulfillment systems.
Delta sync for orders placed during the freeze
The part that makes the window safe.
- Capture orders by timestamp or webhook from the old store and replay them into the new one.
- Make the replay idempotent, so a retry cannot create a duplicate.
- Sync inventory last, from the ERP if you have one.
- Reconcile counts by order number and by value before opening checkout.
- Send order confirmation emails only for orders that need them.
DNS and rollback
Plan both before the day.
Rule of thumb: do not shut down the old store until the new one has taken real orders and payments.
The freeze window to target at 500 orders a day
Targets, not guarantees.
| Item | Target | Why |
| Catalogue and content edits | 24 to 48 hours | Keeps data stable for the final sync |
| Order-capture pause | Minutes to about an hour | Average load is about 21 orders an hour |
| Cutover time of day | Quietest hour in your data | Reduces affected orders |
| Post-launch watch | About 72 hours of on-call support | Catches issues early |
We do not publish measured downtime in minutes for a named migration. Treat these as design targets and rehearse to confirm.
High-volume cutovers, and what we cannot show
We plan cutovers with a rehearsal and a rollback plan. We do not have a published high-volume case with downtime achieved in minutes, so we do not cite one.
Read more: our Shopify migration service
Share your order volume, peak hours and systems, and our migration team will draft a cutover runbook and a target freeze window.
Frequently Asked Questions
Near-zero is realistic, true zero is not. DNS changes, final data syncs and checkout switch-over create a short window where order capture must pause or run on one side only.
One published plan puts the DNS flip at two to four hours, usually on a weekend morning. The visible order pause can be much shorter if the sequence is rehearsed.
Orders placed on the old store during the window are captured by a final delta sync into the new store, so nothing is lost.
About 21 orders an hour on average, more at peak. A one-hour order pause affects roughly that many, which is why many teams schedule cutover at the quietest hour.
Keep the old store intact and ready for rollback until you have confirmed new orders, payments, inventory and fulfillment on the new store. See a realistic migration timeline.
