Congratulations.  What a great way to prove out the usefulness of your service.  Minimal effort to fulfill a need.<p>1. Try to form a relationship with the companies whose APIs you depend upon.  Try to find out their plans for the APIs, if they’ll keep them up, if the terms of service will stay okay for you, and if they are likely to become a competitor.<p>2. Depending upon one, either put your resources into expanding into new areas or replacing the APIs.  Expanding would be preferred, but you may need to do both if one of the companies may become a competitor.<p>Again, sounds like you are in a great spot.  More value provided with less effort is always a good thing.  Sounds like an eloquent solution.  There’s risk, but you recognize it which is important.  Focus on growth if you can rather than de-risking the API usage since there are probably a bunch of other unseen risks and growth will help you find these and deal with them.  Then gradually de-risk the API usage as you grow.