La retbutiko sendis al mi mesaĝon.

La is the definite article in Esperanto, meaning the.

So la retbutiko means the online shop or the webstore, not just an online shop.

A few useful points:

• Esperanto has only one article: la
• It does not change for gender, number, or case
• There is no separate word for English a/an

So:

• retbutiko = online shop / webstore
• la retbutiko = the online shop / the webstore

Esperanto often forms new words by combining smaller word parts into a single word.

retbutiko can be understood as:

• ret- = related to the internet or network
• butiko = shop, store

Together, retbutiko means online shop or internet store.

This kind of compounding is very common in Esperanto. English often writes similar ideas as two words, but Esperanto frequently prefers one combined word.

For example:

• libro = book
• vendejo = shop/place of selling
• librovendejo = bookstore

So retbutiko is perfectly normal Esperanto word-building.

Sendis is the past tense form of sendi = to send.

Esperanto verb endings are very regular:

• -i = infinitive, so sendi = to send
• -as = present, sendas = sends / is sending
• -is = past, sendis = sent
• -os = future, sendos = will send

So La retbutiko sendis al mi mesaĝon means that the sending happened in the past.

One reason learners like Esperanto is that the verb never changes according to the subject:

• mi sendis = I sent
• li sendis = he sent
• ili sendis = they sent

The ending stays -is for all of them.

Al means to.

So al mi means to me.

In this sentence, mi is not the direct object. It is the receiver of the message, so Esperanto uses the preposition al.

Compare:

• mesaĝon = the thing being sent
• al mi = to me, the person receiving it

Why not min?

Because -n usually marks the direct object, and here me is not the direct object. The direct object is mesaĝon.

So:

• La retbutiko sendis mesaĝon al mi = The online shop sent a message to me

That is the normal pattern: sendi ion al iu = to send something to someone

The -n marks the direct object.

The direct object is the thing directly affected by the verb. In this sentence, what was sent? A message.

So:

• mesaĝo = message
• mesaĝon = message as the direct object

This is the accusative ending in Esperanto.

A very common pattern is:

• subject + verb + direct object

Here:

• La retbutiko = subject
• sendis = verb
• mesaĝon = direct object

Even if the word order changes, the -n still tells you that mesaĝon is the object.

Yes. That is also correct, and many learners may actually expect that order first.

Both are natural:

• La retbutiko sendis al mi mesaĝon
• La retbutiko sendis mesaĝon al mi

Because Esperanto marks grammar clearly with endings and prepositions, word order is more flexible than in English.

The difference is mostly about emphasis or style:

• sendis al mi mesaĝon can slightly foreground to me
• sendis mesaĝon al mi may feel a bit more neutral to some speakers

Both mean the same thing.

The subject is La retbutiko.

You can tell because:

• it has no -n ending
• it is the thing doing the action
• the verb sendis describes what it did

So:

• La retbutiko = the sender
• mesaĝon = the thing sent
• al mi = the recipient

Esperanto often makes this easier than English because the object is marked with -n.

Mesaĝo means message.

It contains the letter ĝ, which is pronounced like the g in gem, giant, or judge-like sounds depending on accent, but in Esperanto it is consistently the zh/j sound represented by ĵ/ĝ distinctions. More specifically:

• ĝ sounds like the j in jam
• ĵ sounds like the s in measure

So in mesaĝo, the ĝ is pronounced like English j in message-like pronunciation.

A rough pronunciation guide:

• me-SA-jo

More carefully:

• me as in meh
• saĝ with ĝ like j
• o as a clear o

And with the accusative ending:

• mesaĝon = me-SA-jon

Because after a preposition, Esperanto normally uses the basic form of the pronoun.

So:

• mi = I / me
• al mi = to me
• por mi = for me
• kun mi = with me

You do not add -n just because the English translation uses me.

The important rule is:

• use -n for a direct object
• use a preposition like al when the relationship is shown by that preposition

So al mi is correct because al already tells you the role: to me.

Usually, if you are talking about a specific known online shop, you would say la retbutiko.

If you say just retbutiko sendis al mi mesaĝon, it sounds more like an online shop sent me a message, but Esperanto often does not use an indefinite article at all, so context would have to make that clear.

In many real situations:

• La retbutiko = the shop we already know about, such as the one you ordered from
• Retbutiko without la can sound less specific, more general, or stylistically unusual depending on context

So in an ordinary sentence about a known store, la is the expected choice.

Yes. This is a very useful pattern:

[subject] + sendis + al [person] + [thing]

or

[subject] + sendis + [thing]-n + al [person]

You can reuse it with many words:

• Ŝi sendis al mi leteron. = She sent me a letter.
• La instruisto sendis al ni informon. = The teacher sent us information.
• Mi sendis al li foton. = I sent him a photo.

The key pattern is:

• sendi ion al iu = to send something to someone

That makes this sentence a great model for building your own Esperanto sentences.