> For the complete documentation index, see [llms.txt](https://sub2.gitbook.io/sub2/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://sub2.gitbook.io/sub2/concepts/processors.md).

# Processors

Processors are what make sub2 subscriptions automatic. These are anyone who initiates a transaction processing payments of due subscriptions through the unrestricted `processPayment` function. As a reward, processors earn processing fees varying in size depending on the subscription and how far into the auction period it was processed. Three things go into determining whether a subscription is worth redeeming at a certain point in time: 

* the cost of calling `processPayment` in terms of network fees
* the current income that is obtainable from calling `processPayment`
* the overhead of running the processor (node/provider cost, hardware cost etc)

Given that a subscription is created with a large enough `maxProcessingFee` to cover the costs, it can be assumed that it will be processed.

As more processors search for profitable subscriptions to process, it is expected that the profit margin will diminish. For example,  processor A could be willing to process a subscription at time `n`, but processor B is willing to take a smaller fee and process it at time `n-1`. This competition is healthy for the users of the protocol as they end up paying the *minimum* amount of fee that *any* processor is willing to take.