diff --git a/rfcs/2026-04-forge-s3-flat-file-sharding-strategy.md b/rfcs/2026-04-forge-s3-flat-file-sharding-strategy.md
new file mode 100644
index 0000000..635ccc4
--- /dev/null
+++ b/rfcs/2026-04-forge-s3-flat-file-sharding-strategy.md
@@ -0,0 +1,37 @@
+# RFC: Forge S3 Facade sharding strategy
+
+Status: Experimental
+
+## Authors
+
+- [Alan Shaw](https://github.com/alanshaw)
+
+## Motivation
+
+The Forge S3 Facade must support Multipart uploads via `UploadPart` as well as single part uploads via `PutObject`.
+
+This is a proposal that will allow Forge to support this with minimal changes to the network, leaning on ideas previously proposed by the team:
+
+* https://github.com/storacha/RFC/pull/65
+* https://github.com/storacha/RFC/pull/66
+
+## Design
+
+The Sharded DAG Index will gain a `nodes` property - a list of UnixFS nodes "inlined" in the index (renamed from `blocks` as proposed in [#66](https://github.com/storacha/RFC/pull/66)).
+
+For a given upload (a `PutObject` or `UploadPart` request) the S3 facade will shard data at the current threshold (256MB) and keep track of the CIDs of the shards that have been created as well as the order.
+
+The order is important for retrieval, since we need to serve data from the shards in the order it appears in the object that is being uploaded.
+
+When the `PutObject` request ends or the multipart `CompleteMultipartUpload` request is received, a UnixFS File root node is created that links to ALL shards in order.
+
+A Sharded DAG Index is created, that contains entries for each shard. Each shard entry has a single slice entry which is the slice of the entire shard from byte 0 to (up to) 256MB.
+
+The order in which the shards should be served is encoded in the root UnixFS node, which is added to the Sharded DAG Index `nodes` property.
+
+To enable retrieval Guppy will need to be updated to consider the `nodes` property, and load the node(s) into it's own cache. Retrieval can then proceed as usual.
+
+## References
+
+* https://github.com/storacha/RFC/pull/65
+* https://github.com/storacha/RFC/pull/66