Each extra nine is ten times less downtime and usually far more than ten times the cost. Downtime budgets per month, why chaining services multiplies their failures, what an SLA actually promises, and the five checks a small team should have running.
If a request needs your hosting, your database, your auth provider and a payment API, and each is independently up 99.9% of the time, the request succeeds about 99.6% of the time: nearly three hours of failure a month, not 43 minutes. Every service in the critical path lowers the ceiling.
Take dependencies out of the request path where you can: send email and analytics from a queue.
Degrade instead of failing: if recommendations are down, show the page without them.
Cache, so a dependency outage serves slightly stale data instead of errors.
Book a free 30-minute call. You'll leave knowing what we'd do first and roughly what it costs, whether or not you hire us.
A provider's SLA is usually a promise of service credits, a percentage of that service's bill, if availability falls below a threshold, and you normally have to claim them. It is not a promise the service stays up, and it does not cover your lost revenue. Design for the outage; read the SLA for the refund.
An external check on the home page and one key API route, from outside your hosting provider, alerting a phone. Route 53 health checks are $0.50 a month for AWS endpoints and $0.75 for others.
Error rate and p95 latency on the main routes, alerting on a sustained change. Averages hide the slow requests users notice.
Certificate and domain expiry, at least 14 days ahead.
Queue and background job health. A backlog growing for an hour is an outage nobody sees.
A status page, however simple, so users have somewhere to look besides your inbox.
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As of October 26, 2026. Provided as is, for general information, and accurate to the best of our knowledge on the date shown. Not legal, compliance, tax, financial or other professional advice. Prices, limits and vendor services change; check current vendor documentation before relying on anything here. Terms of use.