What is private and public bucket on AWS S3?

Natali Dev
4 min readJun 18, 2021


S3 or Simple Storage Service is one of the storage solution service provided by AWS S3 [ Amazon Web Service S3 ]

It can be used to store any number of files to a maximum limit of an individual file of 5TB with the help of Multipart API. [ That means if you have a movie/series file of 5.1TB, you cannot upload that into S3]

Upload 5GB file in one go!

But, remember using a single PUT request, you can upload a maximum of a 5GB file in one go.

S3 is known for its durability and it provides 119s of durability, In a simple term that means, if you store 10,000,000 objects with Amazon S3, you can expect to incur a loss of a single object once every 10,000 years. Which is really a great value.

How S3 can do it:

It replicates your file into 3 different data centers, that is one of the reasons why Amazon S3 offers eventual consistency for overwrite PUTS and DELETES in all regions.

That means if you update an existing file in AWS S3 bucket, and immediately you try to read that file, there are chances you will get the old file because it takes some time to replicate the change to all data centres. You have to wait for a min or so to get to see the new change in the file.

Specify storage location:

Even though S3 is a global service, but when you create a bucket, you have to mention which region you want your bucket to be stored.

When you click on Create Bucket, this gives multiple options on different consecutive pages, where you can take your decision to make your bucket as Public or Keep that as private, it’s suggested to keep that private unless it’s necessary.

But, that does not make that public yet to upload and read/write the objects on S3 as a public.

Note: You have to create some Bucket policy to grant access to some IAM users. Its separate topic, In our Lia Infraservices blog, we have explained that in more detail.

Here, You have provided public access to the bucket as well for Everyone and you have to mention if it’s only for the bucket or the objects inside the bucket.

Here, the bucket now shows as “Public”

To make an object inside a bucket, you have to provide it public access.


An S3 bucket is considered as Private if that does not have any Public access provided to any of its ACL or bucket policy.

S3 is bucket if it has provided access for external people to read/write/upload content files.

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Natali Dev

Information Technology- Graduate