What is an SLA Anyway?

If you've ever signed up for a cloud service, email platform, or any software-as-a-service tool, you've probably agreed to a Service Level Agreement (SLA) without thinking much about it. But understanding what an SLA actually is — and what it promises you — could save you money and headaches down the road.

SLA: The Simple Definition

A Service Level Agreement (SLA) is essentially a contract between you and a service provider that defines what level of service you can expect. Think of it as the vendor's promise about how reliable their service will be, and what happens when they don't meet that promise.

Most SLAs focus on uptime — how much of the time the service will be available and working properly. But they can also cover response times, performance metrics, and support quality.

The Anatomy of an SLA

Let's break down what you'll typically find in an SLA:

1. Uptime Guarantee

This is the big number — usually something like "99.9% uptime" or "99.99% availability." It sounds impressive, but let's put it in context:

  • 99% uptime = up to 7.2 hours of downtime per month
  • 99.9% uptime = up to 43 minutes of downtime per month
  • 99.99% uptime = up to 4.3 minutes of downtime per month

Real Example: GitHub's SLA

GitHub promises 99.9% uptime for their paid plans. This means if they're down for more than 43 minutes in a month, they've breached their SLA and you may be entitled to service credits.

2. What Counts as Downtime

Not all problems count as "downtime" for SLA purposes. Most agreements specify that only complete service unavailability counts, not:

  • Planned maintenance (usually with advance notice)
  • Partial functionality issues
  • Problems caused by your own actions or third parties
  • Issues outside the vendor's control (like internet outages)

3. Measurement Windows

SLAs define how uptime is calculated — usually monthly, but sometimes quarterly or annually. A service might have a bad week but still meet their monthly SLA target.

4. Remedies (The Good Stuff)

This is where it gets interesting for customers. When a vendor breaches their SLA, they typically offer service credits — essentially giving you money back or extending your service for free.

Important: Service credits don't automatically appear in your account. You usually have to request them within a specific timeframe (often 30-60 days) and provide proof of the impact.

Common SLA Structures

Here are the most common types of SLA commitments you'll encounter:

Tiered Credits

Many vendors offer increasing credits based on how badly they miss their targets:

Example: AWS S3 SLA

  • 99.9% to 99.0% uptime = 10% service credit
  • 99.0% to 95.0% uptime = 25% service credit
  • Below 95.0% uptime = 100% service credit

Response Time SLAs

For services like support or APIs, SLAs might promise response times rather than just uptime:

  • "Support tickets acknowledged within 4 hours"
  • "API response time under 200ms for 95% of requests"
  • "Critical issues resolved within 24 hours"

What SLAs Don't Cover

It's important to understand the limits of SLA protection:

  • Your actual losses: A $10 service credit doesn't compensate for losing a $1000 deal due to downtime
  • Consequential damages: Most SLAs explicitly exclude liability for business losses
  • Data recovery: Uptime guarantees don't usually cover data loss or corruption
  • Third-party integrations: If your Slack-GitHub integration breaks, that might not be covered

Why SLAs Matter for Your Business

Understanding SLAs helps you in several ways:

  • Set realistic expectations: Know what level of reliability you're actually paying for
  • Choose the right vendors: Compare SLA terms when evaluating services
  • Recover costs: Claim credits when vendors don't meet their promises
  • Plan for outages: Build redundancy where SLAs aren't strong enough
Pro Tip: Don't just look at the uptime percentage. Pay attention to how downtime is measured, what counts as an outage, and how easy it is to claim credits when things go wrong.

The Bottom Line

SLAs are more than legal fine print — they're your safety net when services fail. While they won't make you whole for business disruptions, they do provide some compensation and create accountability for vendors.

The key is knowing what you're entitled to and actually claiming it when the time comes. Most businesses never do, which is exactly what vendors are counting on.

Next time you're evaluating a new service, take a few minutes to read their SLA. You might be surprised by what you find — both the protections you have and the gaps you'll need to plan around.