about-api.md

copyright	lastupdated	keywords	subcollection
years 2017, 2023	2023-11-02	rest, s3, compatibility, api, error	cloud-object-storage

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About the {{site.data.keyword.cos_full_notm}} S3 API

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The {{site.data.keyword.cos_full}} API is a REST-based API for reading and writing objects. {: shortdesc}

It uses {{site.data.keyword.iamlong}} for authentication and authorization, and supports a subset of the S3 API for easy migration of applications to {{site.data.keyword.cloud_notm}}.

This reference documentation is being continuously improved. If you have technical questions about using the API in your application, post them on StackOverflow. Add both ibm-cloud-platform and object-storage tags and help improve this documentation thanks to your feedback.

As {{site.data.keyword.iamshort}} tokens are relatively easy to work with, curl is a good choice for basic testing and interaction with your storage. More information can be found in the curl reference.

The following tables describe the complete set of operations of the {{site.data.keyword.cos_full_notm}} API. For more information, see the API reference page for buckets or objects.

Bucket operations

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These operations create, delete, get information about, and control behavior of buckets.

Bucket operation	Note
GET Buckets	Used to retrieve a list of all buckets that belong to an account.
DELETE Bucket	Deletes an empty bucket.
DELETE Bucket CORS	Deletes any CORS (cross-origin resource sharing) configuration set on a bucket.
GET Bucket	Lists objects in a bucket. Limited to listing 1,000 objects at a time.
GET Bucket CORS	Retrieves any CORS configuration set on a bucket.
HEAD Bucket	Retrieves a bucket's headers.
GET Multipart Uploads	Lists multipart uploads that aren't completed or canceled.
PUT Bucket	Buckets have naming restrictions. Accounts are limited to 100 buckets.
PUT Bucket CORS	Creates a CORS configuration for a bucket.
{: caption="Bucket operation" caption-side="top"}

Object operations

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These operations create, delete, get information about, and control behavior of objects.

Object operation	Note
DELETE Object	Deletes an object from a bucket.
DELETE Batch	Deletes many objects from a bucket with one operation.
GET Object	Retrieves an object from a bucket.
HEAD Object	Retrieves an object's headers.
OPTIONS Object	Checks CORS configuration to see whether a specific request can be sent.
PUT Object	Adds an object to a bucket.
PUT Object (Copy)	Creates a copy of an object.
Begin Multipart Upload	Creates an upload ID for a set of parts to be uploaded.
Upload Part	Uploads a part of an object that is associated with an upload ID.
Upload Part (Copy)	Uploads a part of an existing object that is associated with an upload ID.
Complete Multipart Upload	Assembles an object from parts that are associated with an upload ID.
Cancel Multipart Upload	Cancels upload and deletes outstanding parts that are associated with an upload ID.
List Parts	Returns a list of parts that are associated with an upload ID
{: caption="Object operation" caption-side="top"}

More information about {{site.data.keyword.cos_full_notm}} features and use-cases can be found at ibm.com.