I'm a web developer, and I charge my clients "hosting and maintenance" fees. This covers my raw hosting costs, but it also includes overhead for server maintenance and handling the occasional "critical bugfix". That's usually good enough for my clients.

I now have a client that's looking for a service-level guarantee. I've never done an SLA, but I figured I could offer "99% availability for mission-critical features" and in the case of a failure give a "prorated refund on hosting for time duration of lost availability". It's a relatively simple application, so I'm not expecting to have to troubleshoot very often.

Is there anything I'm not thinking of that would make this type of agreement a bad idea?

  • are you alone or part of a larger group? If alone, this is risky stuff... and did you define all the "mission critical" features? SLA is all about defining and scoping. Commented Jul 3, 2017 at 11:52
  • to achieve 99% availability, your server must have automatic 'fall back' to a backup server and any databases, etc must be updated and available in (at least) 2 different places (not on the same computer. Commented Jul 6, 2017 at 22:31

3 Answers 3


Try to shift up the risk to your provider. Ask them to give you SLA. If they do not give you, there is a reason behind it, and you either should not give SLA for the same reason.

  • 1
    The provider has an SLA for 99.9% uptime, but I don't think their definition of "uptime" is what the client is looking for. I think the client is probably also looking for "availability" -- for example, if the website goes down due to a bug in the code or some other reason.
    – Ben Davis
    Commented Jul 3, 2017 at 16:26

Unless you have 100% access to the server at all times and can make server-level changes, including but not limited to hardware replacement if needed, providing a guarantee seems a bit haphazard.

I always hesitate to guarantee anything which is ultimately on the shoulders of some other company or individual. If you are just reselling hosting... that means ultimately your guarantee would be in the hands of your hosting provider, not you. You would essentially be guaranteeing another company's work/service.

Chances are things will probably run fine and you'll be okay. But there's always that slim chance there's a major issue which could end up costing a lot of time and money to correct, all because you've offered a guarantee. For me, that slim chance is often enough to just find another client.

Disclosure: I quit reselling hosting a few years ago and now merely direct clients to companies I think are worthwhile. For me, personally, the constant influx of "my email isn't working" was enough to get me out of the reselling game.


A service level of 99 % uptime allows the following downtime:

  • Daily: 14m 24.0s
  • Weekly: 1h 40m 48.0s
  • Monthly: 7h 18m 17.5s
  • Yearly: 3d 15h 39m 29.5s

A reliable web hosting solution is unlikely to be down for more than 7 hours per month so you'd likely be quite safe. In the event of a hosting company disaster, you could probably restore a recent backup to a new host and be up and running in less than 7 hours if you had to.

As you say, define a reasonable penalty and exclude any special circumstances out of your control such as Acts of God.

I recommend checking service level agreements of companies in your industry or similar industries for ideas. You can find these online as they are often available to prospective customers and not just customers.

You should charge more for a service with an SLA as you may need to prioritise work for SLA clients, e.g. working outside of normal hours to keep them online in an emergency, and they should pay for this privilege.

Finally, I am not a lawyer and you should probably get someone qualified in this area to check over your ideas.

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