The current price model of nixbuild.net is based solely on the CPU time (as defined below) consumed each month. The CPU time is multiplied by an hourly fee, and the resulting cost is charged once a month.
The current pricing model should be considered introductory. nixbuild.net reserves the right to adjust the hourly CPU time fee, adjust the way CPU time is calculated or make more significant changes to the overall pricing model.
CPU Time Fee¶
The price of 1 CPU hour is currently 0.12 EUR, excluding VAT.
CPU Time Definition¶
Each time a build request is submitted, nixbuild.net will first decide if the build will be executed or if an existing result can be served back to the user. If an existing result can be used, the CPU time is considered to be zero. If the build needs to be executed, resource selection is performed, to decide on how many CPUs and how much memory the build will be allocated. After this, nixbuild.net will allocate the necessary resources. This might involve provisioning new backend builders if there are no available builders. Finally, the virtual sandbox that will host the build is booted on the allocated builder machine. When the sandbox is fully booted, the build time measurement is started. Then, as soon as the build is finished and has produced a stored result, the build time measurement is stopped. If the build failed due to any error for which the the nixbuild.net infrastructure is to be blamed, the measured build time is discarded and the build is retried automatically.
The measured build time is multiplied by the number of CPUs used, and then rounded up to whole seconds. The resulting number is the CPU time of the build. The minimal CPU time of any executed build is therefore 1 second.
At the end of each month, the sum of all (non-discarded) build times for the past month is rounded up to whole hours and multiplied with the hourly fee to produce the invoice amount. Therefore, if any build at all has been executed during the month, the minimal invoice amount will be for 1 CPU hour.
Payments are handled by Stripe, which automatically charges your credit card each month (if you have run any non-free builds during the month).
To set up billing (enabling non-free usage) you use the billing command in the nixbuild.net shell. You will be delegated to a Stripe-hosted web page to enter your credit card details. The nixbuild.net service doesn't store any credit card details itself.