Depois de pagar a fatura, eu vou ver o saldo da conta no aplicativo do banco.

Because depois normally takes the preposition de before a verb in the infinitive.

So:

• depois de pagar = after paying
• not depois pagar

This is a fixed pattern in Portuguese:

• depois de comer = after eating
• depois de estudar = after studying

So in your sentence, Depois de pagar a fatura is the natural way to say After paying the bill.

After depois de, Portuguese commonly uses the infinitive when the subject is understood from the main clause.

In this sentence:

• Depois de pagar a fatura, eu vou ver...

The person who will pay is the same person as eu, so Portuguese can simply use the infinitive pagar.

It works a lot like English after paying.

If you wanted to make the subject explicit, you could also say:

• Depois que eu pagar a fatura, eu vou ver o saldo...

That version is also very common.

Not always. Portuguese often drops subject pronouns when the verb already makes the subject clear.

So both are possible:

• Depois de pagar a fatura, vou ver o saldo...
• Depois de pagar a fatura, eu vou ver o saldo...

Adding eu can:

• give a little emphasis
• make the sentence clearer
• sound more natural in some contexts of spoken Brazilian Portuguese

So eu is optional here, not required.

Because in everyday Brazilian Portuguese, ir + infinitive is very common for future meaning.

So:

• eu vou ver = I am going to see / I will check

A more formal or written future would be:

• verei

But verei sounds more formal, literary, or less common in normal conversation.

In Brazil, people very often prefer:

• vou pagar
• vou ver
• vou ligar
• vou fazer

So eu vou ver is the most natural everyday choice.

Not exactly.

In Brazilian Portuguese:

• fatura usually means an invoice or statement, especially a credit card bill
• conta can mean a bill, an account, or even a math calculation depending on context

In this sentence:

• pagar a fatura probably means pay the bill/statement
• saldo da conta means the account balance

So even though English might use bill or account in different ways, Portuguese is distinguishing two different things here:

• fatura = the bill/statement being paid
• conta = the bank account

This is a very common question for learners.

In Brazil:

• fatura = invoice/statement, often a credit card bill
• boleto = a specific payment slip/document used to make a payment

For example:

• Paguei a fatura do cartão = I paid the credit card bill
• Paguei o boleto da internet = I paid the internet payment slip/bill

Sometimes both relate to something you have to pay, but they are not the same word or the same system.

Because da here means de + a, and it expresses the balance of the account.

• o saldo da conta = the account’s balance / the balance of the account

Portuguese often uses this de + article structure where English might use of or a possessive.

Examples:

• o nome da rua = the name of the street
• a porta do carro = the car door
• o número da casa = the house number

So saldo da conta is the normal way to say account balance.

Portuguese uses definite articles much more often than English.

So where English may say:

• pay bill
• check account balance
• in bank app

Portuguese usually prefers:

• pagar a fatura
• ver o saldo da conta
• no aplicativo do banco

This sounds natural in Portuguese. Leaving out the articles often sounds unnatural or incomplete.

This is something English speakers have to get used to: Portuguese likes to specify nouns with articles even when English does not.

It literally breaks down like this:

• no = em + o = in the
• aplicativo = app/application
• do = de + o = of the
• banco = bank

So:

• no aplicativo do banco = in the bank’s app / on the bank app

This sentence contains two very common contractions:

• em + o = no
• de + o = do

Other common ones are:

• na = em + a
• da = de + a
• dos = de + os
• nas = em + as

Yes. Ver is simple, common, and natural.

• ver o saldo = see/check the balance

Other options:

• checar o saldo = check the balance
• consultar o saldo = consult/check the balance
• olhar o saldo = look at the balance

In Brazilian Portuguese:

• ver and olhar sound very everyday
• checar is common but a bit influenced by English
• consultar can sound slightly more formal or banking-related

So vou ver o saldo is perfectly natural and very common.

By itself, conta can mean different things depending on context:

• bank account
• bill/check at a restaurant
• utility bill
• math problem

But in saldo da conta, the word saldo makes it clear that this is a financial account, because saldo means balance.

So here:

• conta = account

If it meant a restaurant bill, saldo would not make sense.

Yes, absolutely.

These are both natural:

• Depois de pagar a fatura, eu vou ver o saldo...
• Depois que eu pagar a fatura, eu vou ver o saldo...

The difference is mainly structure:

1. Depois de pagar...

   • uses depois de + infinitive
   • compact
   • elegant and very common when the subject is the same

2. Depois que eu pagar...

   • uses a full clause
   • makes the subject explicit
   • also very common in speech

Note that after depois que, Portuguese uses pagar in the future subjunctive, which in this case looks the same as the infinitive:

• quando eu pagar
• depois que eu pagar

The given sentence is very natural, but Portuguese allows some flexibility.

Original:

• Depois de pagar a fatura, eu vou ver o saldo da conta no aplicativo do banco.

Other possible orders:

• Eu vou ver o saldo da conta no aplicativo do banco depois de pagar a fatura.
• Depois de pagar a fatura, vou ver o saldo da conta no aplicativo do banco.

These all work. The original order is nice because it clearly sets up the sequence:

1. pay the bill
2. then check the balance

So the fronted phrase Depois de pagar a fatura sounds very natural.

The original sentence is already natural. But in casual speech, you might also hear:

• Depois de pagar a fatura, vou ver o saldo da conta no app do banco.
• Depois que eu pagar a fatura, vou olhar o saldo no aplicativo do banco.
• Depois de pagar a fatura, vou checar o saldo da conta.

Small spoken-style changes:

• dropping eu
• using app instead of aplicativo
• using olhar or checar instead of ver

So your sentence is good, standard, and natural, but there are several everyday variations too.