diff --git a/doc/book/src/SUMMARY.md b/doc/book/src/SUMMARY.md
index 878c20b3..91ed9836 100644
--- a/doc/book/src/SUMMARY.md
+++ b/doc/book/src/SUMMARY.md
@@ -41,6 +41,7 @@
   - [Miscellaneous notes](./development/miscellaneous_notes.md)
 
 - [Working Documents](./working_documents/index.md)
+  - [S3 compatibility target](./working_documents/compatibility_target.md)
   - [Load balancing data](./working_documents/load_balancing.md)
   - [Migrating from 0.3 to 0.4](./working_documents/migration_04.md)
   - [Design draft](./working_documents/design_draft.md)
diff --git a/doc/book/src/working_documents/compatibility_target.md b/doc/book/src/working_documents/compatibility_target.md
new file mode 100644
index 00000000..c6c58007
--- /dev/null
+++ b/doc/book/src/working_documents/compatibility_target.md
@@ -0,0 +1,105 @@
+# S3 compatibility target
+
+If there is a specific S3 functionnality you have a need for, feel free to open
+a PR to put the corresponding endpoints higher in the list.  Please explain
+your motivations for doing so in the PR message.
+
+| Priority                   | Endpoints  |
+| -------------------------- | --------- |
+| **S-tier** (high priority) | |
+| 							 | HeadBucket |
+| 							 | GetBucketLocation |
+| 							 | *CreateBucket* |
+| 							 | *DeleteBucket* |
+| 							 | ListBuckets |
+| 							 | ListObjects |
+| 							 | ListObjectsV2 |
+| 							 | HeadObject |
+| 							 | GetObject |
+| 							 | PutObject |
+| 							 | CopyObject |
+| 							 | DeleteObject |
+| 							 | DeleteObjects |
+| 							 | CreateMultipartUpload |
+| 							 | CompleteMultipartUpload |
+| 							 | AbortMultipartUpload |
+| 							 | UploadPart |
+| 							 | *ListMultipartUploads* |
+| 							 | *ListParts* |
+| **A-tier** (will implement)     | |
+| 							 | *GetBucketCors* |
+| 							 | *PutBucketCors* |
+| 							 | *DeleteBucketCors* |
+| 							 | *UploadPartCopy* |
+| 							 | *GetBucketWebsite* |
+| 							 | *PutBucketWebsite* |
+| 							 | *DeleteBucketWebsite* |
+| ~~~~~~~~~~~~~~~~~~~~~~~~~~ | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ |
+| **B-tier** | |
+| 							 | GetBucketAcl |
+| 							 | PutBucketAcl |
+| 							 | GetObjectLockConfiguration |
+| 							 | PutObjectLockConfiguration |
+| 							 | GetObjectRetention |
+| 							 | PutObjectRetention |
+| 							 | GetObjectLegalHold |
+| 							 | PutObjectLegalHold |
+| **C-tier** | |
+| 							 | GetBucketVersioning |
+| 							 | PutBucketVersioning |
+| 							 | ListObjectVersions |
+| 							 | GetObjectAcl |
+| 							 | PutObjectAcl |
+| **garbage-tier**   | |
+| 							 | DeleteBucketEncryption |
+| 							 | DeleteBucketAnalyticsConfiguration |
+| 							 | DeleteBucketIntelligentTieringConfiguration |
+| 							 | DeleteBucketInventoryConfiguration |
+| 							 | DeleteBucketLifecycle |
+| 							 | DeleteBucketMetricsConfiguration |
+| 							 | DeleteBucketOwnershipControls |
+| 							 | DeleteBucketPolicy |
+| 							 | DeleteBucketReplication |
+| 							 | DeleteBucketTagging |
+| 							 | DeleteObjectTagging |
+| 							 | DeletePublicAccessBlock |
+| 							 | GetBucketAccelerateConfiguration |
+| 							 | GetBucketAnalyticsConfiguration |
+| 							 | GetBucketEncryption |
+| 							 | GetBucketIntelligentTieringConfiguration |
+| 							 | GetBucketInventoryConfiguration |
+| 							 | GetBucketLifecycleConfiguration |
+| 							 | GetBucketLogging |
+| 							 | GetBucketMetricsConfiguration |
+| 							 | GetBucketNotificationConfiguration |
+| 							 | GetBucketOwnershipControls |
+| 							 | GetBucketPolicy |
+| 							 | GetBucketPolicyStatus |
+| 							 | GetBucketReplication |
+| 							 | GetBucketRequestPayment |
+| 							 | GetBucketTagging |
+| 							 | GetObjectTagging |
+| 							 | GetObjectTorrent |
+| 							 | GetPublicAccessBlock |
+| 							 | ListBucketAnalyticsConfigurations |
+| 							 | ListBucketIntelligentTieringConfigurations |
+| 							 | ListBucketInventoryConfigurations |
+| 							 | ListBucketMetricsConfigurations |
+| 							 | PutBucketAccelerateConfiguration |
+| 							 | PutBucketAnalyticsConfiguration |
+| 							 | PutBucketEncryption |
+| 							 | PutBucketIntelligentTieringConfiguration |
+| 							 | PutBucketInventoryConfiguration |
+| 							 | PutBucketLifecycleConfiguration |
+| 							 | PutBucketLogging |
+| 							 | PutBucketMetricsConfiguration |
+| 							 | PutBucketNotificationConfiguration |
+| 							 | PutBucketOwnershipControls |
+| 							 | PutBucketPolicy |
+| 							 | PutBucketReplication |
+| 							 | PutBucketRequestPayment |
+| 							 | PutBucketTagging |
+| 							 | PutObjectTagging |
+| 							 | PutPublicAccessBlock |
+| 							 | RestoreObject |
+| 							 | SelectObjectContent |