nour - im trying to help so please dont be upset or offended...
the idea of getting access to a couple APIs and annotating some variants is anywhere from suboptimal (if a research question) to dangerous (if used for patient care). i dont know what you are planning to build or why, but id urge you to slow down and do some reading. let me explain.
at this point, every reputable database for sequence variant interpretation is going to have an API - finding APIs is not the problem. there are many tools, many databases, many software packages, many APIs ... if your approach is just "what are some APIs" you may finish quickly, but will the annotations mean anything? who knows - some are out of date, some may not fit your goals (clinical vs. something else?) etc.
what you need to do is the opposite. go slowly, tabulate the available options, then understand what each data source contains, how it is constructed, why it is used by people, and what makes it better or worse for your goals than the comparable tools.
depending on your goals, consensus recommendations on variant annotation may exist. we dont know if your data are clinical, bioinformatic, or what.. so its hard for us to guess what the right statement could be. AMP/ACMG could be a good fit; the 2015 guidelines are here: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4544753/ since then many articles discussing it have been written and the guidelines themselves updated..
a search for "variant interpretation guidelines" returns:
https://www.sciencedirect.com/science/article/pii/S0002929720303566
https://www.nature.com/articles/gim201842
but even here, just knowing which tools AMP/ACMG recommends isnt the best way to go. Its knowing WHY those are recommended.
API's for
clinvar
- https://www.ncbi.nlm.nih.gov/clinvar/docs/maintenance_use/COSMIC - https://clinicaltables.nlm.nih.gov/apidoc/cosmic/v3/doc.html
clingen - https://search.clinicalgenome.org/kb/downloads