sokukounyuu ga dekimasu.

It’s usually read そくこうにゅう.

• 即 = immediate / instant
• 購入 = purchase / buying

So 即購入 literally means something like immediate purchase or instant buying.

In online selling contexts, it often means buying right away without asking first.

This is a very common learner question.

In 即購入ができます, the verb is できます.
With できる, the thing that is possible is often marked with が.

So the structure is:

• 即購入 = immediate purchase
• が = marks the thing that is possible
• できます = is possible / can be done

That is why が sounds natural here.

Compare:

• 購入をする = to make a purchase
• 購入ができる = to be able to make a purchase

English learners often expect を because purchase feels like an object, but with できる, Japanese commonly switches to が.

Yes, functionally it is closely related.

する = to do
できる = can do / be able to do / be possible

For many suru-nouns like 購入, Japanese often uses:

• 購入する = to purchase
• 購入できる or 購入ができる = can purchase / purchase is possible

So in this sentence, できます expresses ability or possibility in a polite way.

It sounds a bit like:

• Immediate purchase is possible
• You can buy it right away
• Instant purchase is allowed

In many real-life situations, especially online marketplaces, it often implies:

• You do not need to comment first
• You may go ahead and buy it immediately

So the nuance is not just speed, but also permission / availability.

The subject is not stated explicitly.

Japanese often leaves out the subject when it is clear from context. Depending on the situation, this sentence could mean:

• You can purchase it immediately
• This item can be purchased immediately
• Immediate purchase is possible

In an online listing, the natural interpretation is usually about the item/listing:

• This item is available for immediate purchase

Yes, very common.

On Japanese flea-market and resale apps, sellers often write things like:

• 即購入OKです = Immediate purchase is OK
• 即購入可能です = Immediate purchase is possible
• 即購入できます = You can purchase immediately

This usually means the buyer does not need to ask:

• Can I buy this?
• Is this still available?

They can just proceed with the purchase.

It actually can be said that way too.

Both are understandable:

• 即購入ができます
• 即購入できます

The version with が makes the structure a little more explicit:
Immediate purchase is the thing that is possible.

The version without が is also common and may feel a bit more direct or conversational in some contexts.

So:

• 即購入ができます = grammatically clear and natural
• 即購入できます = also natural, especially in casual written contexts

Yes, but it changes the nuance.

• 即購入ができます = neutral statement of possibility
• 即購入はできます = as for immediate purchase, it is possible

Using は often adds contrast or emphasis. For example, it might sound like:

• At least immediate purchase is possible
• Immediate purchase is possible, though maybe something else is not

So if you just want a plain statement, が is the more neutral choice.

It is understandable Japanese, but it is especially common in specific contexts like:

• online marketplaces
• resale apps
• e-commerce listings
• social media selling posts

It is not the most typical phrase for ordinary daily conversation about shopping in a store. It feels more like a set phrase used in online buying/selling culture.

In normal Japanese writing, you would usually write it without spaces:

即購入ができます。

The spaces are probably only there to help learners see the parts more clearly:

• 即購入
• が
• できます

So the spaced version is useful for study, but not standard Japanese formatting.

Yes.

できます is the polite -ます form of できる, so the sentence is polite and neutral.

Compare:

• 即購入ができます。 = polite
• 即購入ができる。 = plain form

In ads, listings, customer communication, and general public writing, the polite form is very common.

Yes, but the nuance is a little different.

• 即購入できます = immediate purchase is allowed/possible; often a set phrase in online selling
• すぐ購入できます = you can purchase it soon/right away

すぐ購入できます focuses more on timing.
即購入できます often carries the marketplace nuance of no prior confirmation needed.

So they are similar, but 即購入 is the more typical expression in that specific online-sales context.