Заказчик и исполнитель согласовали ставку.

Because the subject is actually two people/entities joined by и: заказчик и исполнитель.

In Russian, just like in English, a compound subject with and normally takes a plural verb:

• Заказчик согласовал ставку. = one person agreed the rate.
• Заказчик и исполнитель согласовали ставку. = two parties agreed the rate.

So согласовали is the past tense plural form.

They are in the nominative case, because they are the subject of the sentence.

You can tell because these are the basic dictionary forms:

• заказчик = client/customer who commissions work
• исполнитель = performer/executor/contractor

In this sentence, they are the ones doing the action of agreeing, so nominative is expected.

Because ставку is the accusative singular form of ставка.

The verb согласовать is transitive here, so it takes a direct object:

• согласовать что? → ставку

Since ставка is a feminine noun ending in -а, its accusative singular changes to -у:

• nominative: ставка
• accusative: ставку

So the sentence structure is:

• Заказчик и исполнитель = subject
• согласовали = verb
• ставку = direct object

Согласовали is:

• past tense
• plural
• from the verb согласовать
• perfective aspect

The perfective aspect is important here: it shows the action as completed/result achieved.

So согласовали suggests that the two sides successfully reached agreement.

Compare:

• согласовывали = they were agreeing / they used to discuss and coordinate
• согласовали = they agreed / finalized agreement

Because the sentence describes a completed result: the rate has already been agreed.

Russian often uses:

• imperfective for process, repetition, or background action
• perfective for a finished action or outcome

Here the focus is not on the negotiations themselves, but on the fact that the agreement was reached.

So:

• согласовывали ставку = they were negotiating/working out the rate
• согласовали ставку = they finished agreeing on the rate

In this context, ставка usually means something like:

• rate
• fee
• pay rate
• charge
• sometimes bid depending on context

It is a flexible word, so the exact English translation depends on the situation.

For example:

• in employment/freelance context: rate
• in finance or taxes: rate
• in betting: stake/wager
• in auctions/tenders: sometimes bid

In this sentence, with заказчик and исполнитель, the most natural meaning is the agreed rate/fee for the work.

These are common business/contract terms.

• заказчик = the party that orders or commissions the work
  Often: client, customer, commissioning party.
• исполнитель = the party that performs or carries out the work
  Often: contractor, provider, performer, executor.

So this sentence sounds like formal or business Russian, especially in contracts, project work, or services.

Because Russian uses a different verb pattern.

English says:

• agree on something

But Russian often says:

• согласовать что-то = to agree/approve/finalize something

So ставку is a direct object, not part of a prepositional phrase.

A useful comparison:

• Они согласовали ставку. = They agreed/finalized the rate.
• Они договорились о ставке. = They came to an agreement about the rate.
• Они согласились на ставку. = They agreed to the rate.

These are similar in meaning, but the grammar is different.

Yes. Russian word order is flexible because case endings show grammatical roles.

The neutral word order here is:

• Заказчик и исполнитель согласовали ставку.

But you could also say:

• Ставку согласовали заказчик и исполнитель.
• Заказчик и исполнитель ставку согласовали.

These versions are grammatical, but the emphasis changes.

For example:

• putting ставку first can emphasize the rate
• putting the verb later can sound more contrastive or stylistically marked

For a learner, the original sentence is the most neutral and natural starting point.

It would be:

Зака́зчик и исполни́тель согласова́ли ста́вку.

This helps with pronunciation:

• зака́зчик
• исполни́тель
• согласова́ли
• ста́вку

Stress matters a lot in Russian, so it is worth learning new words together with their stress.

Not exactly.

• согласовать usually means to coordinate, approve, agree/finalize something
• согласиться means to agree, to consent

Compare:

• Они согласовали ставку. = They agreed/finalized the rate.
• Он согласился на ставку. = He agreed to the rate.

So согласовать often focuses on reaching an agreed version of something, while согласиться focuses more on a person giving consent.

Russian does not have articles.

So заказчик, исполнитель, and ставку can mean:

• the client / the contractor / the rate
• or sometimes a client / a contractor / a rate

The exact meaning comes from context.

In this sentence, because it sounds like a specific business situation, English usually translates it with the:

• the client and the contractor agreed the rate

But Russian itself does not mark that with articles.

It sounds neutral to somewhat formal.

The words заказчик and исполнитель are common in:

• contracts
• project management
• legal/business language
• service agreements

In everyday speech, people might choose less formal words depending on context, such as:

• клиент instead of заказчик
• a more specific job title instead of исполнитель

But the original sentence is perfectly normal Russian, especially in professional contexts.