Peak Sales Week: A Systems Readiness Checklist

Peak sales week does not break the part of your business that customers see. It breaks stock synchronisation, payment provider limits, notification queues and the admin panel your own staff use, and it breaks them in that order. Six weeks out is enough time to find those limits deliberately rather than discovering them on the day.

This guide is written for an owner or manager who has to ask the right questions of a development team, without being able to read the code themselves.

Key takeaways

• Test the checkout path under load, not the homepage: the homepage is cached and will be fine; the parts that touch stock, payment and orders are not.
• The back office fails before the storefront does: when orders arrive faster than usual, the tool your staff use to process them is usually the first thing to slow down.
• Freeze changes before the week, not during it: a deploy made under pressure is the most common cause of an outage during a campaign.
• Agree who is reachable and how, in writing: an escalation list decided in advance is worth more than any amount of monitoring.

Ask what load has actually been tested against

The question to ask is not "will it hold". It is "what number was it tested against, and where did it start to fail". Any team that has done the work can answer both. A team that answers only with reassurance has not done it.

Pick the number together from last year's peak, then test well above it. Two useful figures: concurrent visitors, and orders per minute. The second is the one that matters, because it is what drives writes to stock, payments and order records.

Know which parts break first

The storefront is usually the most resilient part of the system, because it is read-heavy and can be cached. The fragile parts are the ones that write.

• Stock synchronisation. If stock lives in an ERP or a warehouse system and is synced on a schedule, the schedule that works in October is often too slow in November, and overselling begins.
• Payment provider limits. Providers apply rate limits and fraud thresholds. These are usually adjustable, and the adjustment takes days of notice rather than minutes.
• Notification queues. Order confirmations, SMS and emails queue up behind each other. Customers who do not get a confirmation email contact support, which then becomes the bottleneck.
• The admin panel. Staff processing orders on a slow internal tool is the failure nobody plans for, and it is often the most expensive one.
• Third-party integrations. Shipping, invoicing and accounting systems all have their own limits, and they are outside your control.

Freeze what can be frozen

Agree a date after which nothing is deployed except a fix for something that is broken. Two weeks before the campaign is a reasonable point for most businesses.

The reason is simple: during the week itself, every change is made quickly and under pressure, which is exactly when mistakes happen. A discount rule adjusted at nine in the evening has ended more campaigns than any traffic spike.

Decide the fallback before you need it

For each of the failure modes above, decide now what the response is and who makes the call.

• If stock sync falls behind, do you keep selling or pause the affected products?
• If the payment provider rejects traffic, is there a second provider configured and tested?
• If confirmation emails stop, who tells customers, and through which channel?
• Who can approve taking a campaign down, at two in the morning, without a meeting?

Write these down on one page. The page is the deliverable, not a document nobody reads.

Agree the support arrangement in writing

Your development partner's normal working hours are not the campaign's hours. Before the week, agree response times, who is reachable, through which channel, and what counts as an emergency. If this is not written down, it does not exist.

The same applies internally. One named person with the access and the authority to act beats five people waiting for approval.

Measure the week while it happens

Decide in advance the three or four numbers you will watch: orders per minute, checkout completion rate, error rate, and time to process an order internally. Having these visible on one screen turns arguments into observations, both during the week and afterwards.

Related guides

• What this depends on getting right is set out in inventory management system planning.
• If payment capacity is the constraint, payment integration planning covers what to agree with providers in advance.
• If the campaign exposes work being done by hand, the hidden cost of spreadsheet workflows is the follow-up.

If preparing for the campaign uncovers work that needs product, engineering or integration support before November, Discuss Your Plan.