Learn Croatian: Ažuriramo server da optimiziramo bazu. - We update the server to optimize the database.

In English, we often express purpose using the infinitive ("to optimize"). In Croatian, purpose is instead usually expressed with da (that / in order to) followed by a conjugated verb in the present tense. Literally, this sentence is structured as "We update the server so that we optimize the database."

Both server and bazu are direct objects. Why does baza change to bazu, but server stays the same?

Both nouns are in the accusative case because they are the direct objects being acted upon. Baza is a feminine noun, and feminine nouns ending in -a change to -u in the accusative. Server is a masculine inanimate noun (a non-living thing), and for these nouns, the accusative form is identical to their basic dictionary form.

Both verbs in this sentence (ažuriramo, optimiziramo) have a very similar ending. Is this common for tech vocabulary?

Yes! The infinitive forms are ažurirati (to update) and optimizirati (to optimize). In Croatian, foreign loanwords and international tech terms are almost always adapted into verbs by adding the suffix -irati. When conjugated in the present tense for the "we" form, this suffix becomes -iramo.

Doesn't the word for "database" usually translate to baza podataka? Why is it just bazu here?