In the USA, the average salary of a Hadoop developer in India is $128k/yr. A Junior Hadoop developer can get $119k/yr on average. A Senior Hadoop developer can get $178k/yr on average. According to Glassdoor, 33372 job postings for Hadoop developers last month alone in the USA.
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You can watch this video on Hadoop developer to choose the best learning path to become a Hadoop developer: