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Developer Guides
Data Storage

How SkinsRestorer stores data

Why does SR need a .skin file?

SkinsRestorer uses .skin files to keep a cached version of the skin on your server. It contains the same data that Mojang would send to your server when you are in online mode. We cache the information in a file for you, so we need to make fewer requests to the Mojang API and can allow skins even when Mojang servers are down.

The .skin file format

The skin file uses a basic format to store skin data. Here is an example:

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
1633160574367
  1. skin data/value → Holds links to the Mojang texture servers for the client to download. Is stored in base64. Read more in the section below.
  2. skin signature → A unique signature that signs the skin data. Only Mojang can create these. The client verifies when receiving the data that it corresponds to the skin data and will not accept it if it is invalid.
  3. timestamp → When this skin file expires, and we will request the skin data again.

How to decode skin data

The output of the Mojang session server is encoded in Base64. You can use a base64 decoder on the skin data for information about the skin: [https://www.base64decode.org/live (opens in a new tab)]

The output should look like this: {"timestamp":1552224010185,"profileId":"069a79f444e94726a5befca90e38aaf5","profileName":"Notch","signatureRequired":true,"textures":{"SKIN":{"url":"http://textures.minecraft.net/texture/292009a4925b58f02c77dadc3ecef07ea4c7472f64e0fdc32ce5522489362680"}}}

  1. timestamp → shows the date in epoch time [see https://www.epochconverter.com/ (opens in a new tab)]
  2. profileId → The unique player Mojang uuid [see https://api.mojang.com/user/profiles/(id)/names (opens in a new tab)]
  3. profileName → shows the player name (does not have to match the .skin name)
  4. signatureRequired → this MUST be true (as we need signed ones.)
  5. url → the skin data

How we request the .skin file

We use multiple APIs to request the skin. Before we can request the skin, we need the player UUID:

Mojang:

After we gain the unique id we can use it to request a signed skin:

Mojang:

SkinsRestorer API