S3Vault

S3Vault stores your players' data in Amazon S3 without a backend of your own. Save Game To Cloud and Load Game From Cloud move any Save Game object to and from S3 with one node each, so a save follows the player to every device.

Upload File and Download File stream data from and to disk instead of loading it into memory, report byte progress, and switch to parallel multipart uploads above a size you choose. Downloads are written to a temporary file and renamed only when complete, so a cancelled or failed transfer never leaves a broken file. Upload and Download Bytes or String handle small objects such as settings, profiles and JSON.

Download Folder fetches every object below a prefix - ideal for downloadable content packs, seasonal content or mod files - and can skip files that are already up to date. Upload Folder sends a whole directory. List Objects pages through a bucket with folders, sizes, dates and ETags; Get Object Info reads size, content type and metadata without downloading; Copy Object makes server-side backups; Delete Objects removes a list of keys or a whole folder in batches of 1000. Get Presigned URL creates temporary GET or PUT links that work in a browser, a media player or another service without AWS credentials.

Players get credentials from an Amazon Cognito identity pool: as guests, or signed in with a token from a Cognito user pool, Google, Apple, Facebook or any OpenID provider through Set Login Token. A Key Prefix such as players/{IdentityId} places every key in the player's own folder and matches the IAM policy variable for Cognito identities, so each player can only reach their own files; the documentation includes a ready-made policy. Static keys and the default AWS credential chain are available for development, dedicated servers and tools.

Every latent node can be cancelled: running transfers stop and unfinished multipart uploads are aborted. Requests run on background worker threads with automatic retries, so the game thread never blocks, and every result arrives back on the game thread.

S3Vault is part of the Alpha XP AWS collection for Unreal Engine 4.27 and 5.8. It includes the AWS SDK for C++ prebuilt for Win64, Linux and Android, ships with styled HTML documentation, and is compiled warning-free against clean UE 4.27 and UE 5.8 projects.

Key features

• Save Game To Cloud / Load Game From Cloud for any Save Game object
• Upload / Download File streamed from and to disk, with byte progress and safe ".part"
• Multipart uploads above a configurable threshold (Transfer Manager), optional S3
• Upload / Download Bytes and String (UTF-8) for small objects
• Download Folder (with Skip Existing) and Upload Folder for content packs, with file
• List Objects with folders and paging, Get Object Info, Copy Object, Delete Object,
• Get Presigned URL for GET and PUT links
• Per-player folders with the {IdentityId} key token, plus {Region}; absolute keys with
• Amazon Cognito identity pools for guest and signed-in players (Set Login Token for any
• Static keys (development and servers) and the default AWS credential chain
• Content type from the file extension, user metadata on uploads
• Cancellable latent nodes; background worker threads; all results delivered on the game

Blueprint & C++ API

Every call is reachable from more than one place — pick the entry point that fits your project:

Callable runs when executed · Pure no exec pin, returns a value · LatentAsync finishes later and fires its outputs

S3Vault 2

Config 4

Identity 5

Events & delegates

Bind these in Blueprint (drag off the object → Bind Event) or with AddDynamic in C++.

Project settings

Configure once under Project Settings › Plugins › S3Vault — values are saved to the project's config .ini, so they travel with the project and your build.

Options & enums

Compatibility

One ready-made build per engine version is included in the download — copy the one that matches your project.

Technical details

What's in the download

Quick start

1. Unzip the download and pick the build that matches your engine (4.27 · 5.8).
2. Copy the S3Vault folder into your project's Plugins/ folder (create it if needed).
3. Open the project, enable S3Vault under Edit › Plugins and restart the editor.
4. Fill in Project Settings › Plugins › S3Vault.
5. Right-click in any Blueprint graph and search S3Vault — or include the public headers from C++.
6. Package for your target platform (Windows, Linux, Android).

Good to know