Перед отправкой я проверю данные в приложении ещё раз.

Because the preposition перед (before) requires the instrumental case.
So отправка (sending/dispatch) becomes отправкой (instrumental singular): перед отправкой = before the sending / before submitting.

Отправка is a noun (“sending/dispatch/submission”), not a verb. Russian often uses a noun after перед.

A more “verb-like” option is:

• Перед тем как отправить, я проверю данные ещё раз. = “Before I send (it), I’ll check the data again.”

Both are normal; Перед отправкой… is concise and common in instructions and UI contexts.

Проверю is future tense of the perfective verb проверить (“to check/verify (and finish checking)”).

• я проверю = “I will check (and complete the check)”
• я проверяю (imperfective) usually means “I’m checking” (right now) or “I check (habitually)”

In this sentence, the idea is a one-time action in the future, so проверю fits best.

Perfective is used because the speaker intends a single completed check before the sending happens. The sentence implies: “I’ll do a final check (once) and then proceed.”

If you used imperfective, it would change the feel:

• Перед отправкой я проверяю данные ещё раз. = “Before sending, I (usually) check the data again.” (habit/routine)

Данные is in the accusative plural (direct object of проверю).
For inanimate plural nouns, accusative = nominative, so данные looks the same in both cases.

Meaning-wise, it functions as “the data / the details” that you check.

Данные can mean both, depending on context:

• In a technical context: “data” (information in the system)
• In a form/app context: “details” (your entered info: name, address, etc.)

The phrase в приложении strongly suggests a UI/form context, so “details/info in the app” is very plausible.

Russian typically uses:

• в for being inside something conceptual or bounded (an app, a program, a building): в приложении
• на for surfaces, platforms, events, some institutions/sites (e.g., на сайте, на платформе)

For an app, в приложении is the default: “in the app.”

It’s prepositional case (also called “locative” in some contexts) because it follows в in the sense of “in/within (a place).”

Base form: приложение
Prepositional singular: в приложении

Ещё раз means “one more time / again” with an emphasis on repetition as a counted event: “check it again (an additional time).”

Снова also means “again,” but is often more general (“again, anew”) and sometimes less “counted.”

Common alternatives:

• ещё раз = one more time (very common)
• снова = again
• ещё разок = again (a bit more casual)

In careful spelling, it’s ещё with ё, pronounced roughly like yeshchYO (stress on the last syllable).
In many texts, especially informal or when typography is limited, ё is written as е: еще. Native speakers still read it as ещё from context.

Yes. Russian often omits the subject pronoun when it’s obvious from the verb ending.

• Перед отправкой проверю данные в приложении ещё раз. = perfectly natural, slightly more concise. Including я can add a bit of emphasis (“I will…”).

Word order is flexible. The original is neutral and clear. These are also natural:

• Перед отправкой я ещё раз проверю данные в приложении.
• Перед отправкой я проверю ещё раз данные в приложении. (possible, but can sound slightly more marked)

Typically ещё раз sits near the verb it modifies: ещё раз проверю.