My sentence starts with a noun:
Shall I add "The":
The HyperText Transfer Protocol (HTTP) is becoming ..
or leave it without an article:
HyperText Transfer Protocol (HTTP) is becoming ..
Whether it's at the start of a sentence or not doesn't matter - the question is whether it's appropriate to use the definite article in this case. If you see this as a noun phrase where protocol is being modified by hypertext transfer, then you certainly need a determiner, and as there's just the one such protocol you would want the. However, you can also see HyperText Transfer Protocol as a proper noun.
Proper nouns sometimes use definite articles, and sometimes don't. Each of them develops their own convention. Google ngram suggests that it is used with the sometimes, usually not, but enough that using the wouldn't be seen as incorrect.