S3 Compatibility

Client Requirements

• Use path-style addressing.
• Use credentials created on the S3 users page or with synaps3 admin s3-user create.
• Use TLS for production traffic, natively or through your own proxy.

Stable Limits

• Object size: 127 to 1,065,353,216 bytes. Smaller and larger objects are rejected with EntityTooSmall or EntityTooLarge.
• Object keys: valid UTF-8, no NUL character, at most 1,024 bytes.
• Multipart uploads: at most 10,000 parts. The completed object must also be within the object size limit.

Operation Matrix

Area	Operation	Status	Notes
Bucket	CreateBucket	Supported
Bucket	HeadBucket	Supported
Bucket	ListBuckets	Supported
Bucket	DeleteBucket	Not supported	Returns 501 NotImplemented.
Bucket	GetBucketVersioning	Supported	Buckets are always versioning-enabled.
Bucket	PutBucketVersioning	Partial	Accepts Enabled; rejects Suspended.
Bucket ACL	GetBucketAcl	Supported
Bucket ACL	PutBucketAcl	Supported	Grants are enforced; see Access Control.
Object ACL	GetObjectAcl, PutObjectAcl	Not supported
Bucket policy	GetBucketPolicy, PutBucketPolicy, DeleteBucketPolicy	Not supported	Policies are not stored or enforced.
Bucket tagging	GetBucketTagging, PutBucketTagging, DeleteBucketTagging	Not supported
Object tagging	GetObjectTagging, PutObjectTagging, DeleteObjectTagging	Not supported
Ownership controls	GetBucketOwnershipControls	Partial	Reports BucketOwnerPreferred.
Ownership controls	PutBucketOwnershipControls	Partial	Accepts only BucketOwnerPreferred.
Ownership controls	DeleteBucketOwnershipControls	Partial	The bucket keeps BucketOwnerPreferred.
Object	PutObject	Supported
Object	GetObject	Supported	Supports a single byte range. A range read of an object that is not cached downloads the whole object from the storage provider.
Object	HeadObject	Supported	Returns custom metadata of the requested version.
Object	DeleteObject	Supported	See Versioning and Deletion.
Object	DeleteObjects	Supported	1 to 1,000 keys. Reports failures per key; Quiet=true omits successful keys.
Object	CopyObject	Supported	The source must be in the cache or have a committed replica.
Object	ListObjects	Supported	Marker pagination.
Object	ListObjectsV2	Supported	Continuation-token pagination.
Object	ListObjectVersions	Supported	Lists versions and delete markers.
Object	GetObjectAttributes	Partial	For multipart objects, omits TotalPartsCount from ObjectParts and the overall Checksum.
Multipart	CreateMultipartUpload	Supported
Multipart	UploadPart	Supported
Multipart	UploadPartCopy	Partial	Whole-object copy only; a source range returns NotImplemented.
Multipart	CompleteMultipartUpload	Supported
Multipart	AbortMultipartUpload	Supported
Multipart	ListMultipartUploads	Supported
Multipart	ListParts	Supported

Server-side encryption is not supported; requests with customer-provided keys (SSE-C) return 501 NotImplemented.

Access Control

Bucket ACL grants allow other S3 users to read, write, and list according to the granted permission. Even FULL_CONTROL does not allow GetObjectAttributes, deleting a specific version, ListParts, AbortMultipartUpload, or changing bucket configuration; these need the bucket owner or an S3 user with the admin role. A user with write permission can create and complete multipart uploads, but needs the owner or an admin to list parts or abort them.

Versioning and Deletion

Buckets always keep versions.

• DeleteObject without versionId adds a delete marker.
• DeleteObject with versionId deletes that version or delete marker immediately, or fails; it is never queued.
• Deleting a data version fails with 400 InvalidRequest while its storage work is active or a submitted Filecoin transaction awaits confirmation. Failed storage work that never submitted a transaction does not block it, and storage work never blocks deleting a delete marker. In DeleteObjects, the error applies only to that key.
• In DeleteObjects, a key that resolves outside the bucket, such as ../file.txt, rejects the whole request before anything is deleted.

After a data version is deleted, SynapS3 removes the remote replicas that no other version uses, and asks each storage provider to delete its copy. A storage provider that does not support deletion keeps its copy. Until the removal finishes, usually within minutes, uploading the same bytes to that bucket returns 503 SlowDown; a later upload stores them as new data.

Client setup examples are in S3 Clients.