Compute Engine can be setup to use Googles (very nice) image processing tools:
https://cloud.google.com/functions/docs/tutorials/ocr

The nice thing about google is that you get a certain amount each month free. And they use Node.js so moving part of it local is easy. The down side is that you must hope google doesn't abandon the service, change the pricing, or generally dick something else up on you. Hopefully, others have better options for local FOSS OCR.