IPFS and 
Filecoin.
#About
NFT.Storage is a long-term storage service designed for off-chain NFT data (like metadata, images, and other assets) for up to 31GiB in size per individual upload. Data is content addressed using IPFS, meaning the URI pointing to a piece of data (“ipfs://…”) is completely unique to that data (using a content identifier, or CID). IPFS URLs and CIDs can be used in NFTs and metadata to ensure the NFT forever actually refers to the intended data (eliminating things like rug pulls, and making it trustlessly verifiable what content an NFT is associated with).
NFT.Storage stores many copies of uploaded data on the public IPFS network in two primary ways: in dedicated IPFS servers managed by NFT.Storage, and decentralized on Filecoin. Since IPFS is a standard used by many different storage services, it's easy to redundantly store data uploaded to NFT.Storage on any other IPFS-compatible storage solution from pinning services, to your local IPFS node, to other storage networks like Arweave or Storj. And as time goes on, NFT.Storage will increasingly decentralize itself as a public good!
#Store
Just upload your data and you'll receive an IPFS hash of the content (a "CID," or content address) that you can use to make an IPFS URL (ipfs://<cid>). Use this IPFS URL in your NFT data to refer to off-chain data (e.g., the metadata field in your NFT, the image field in your metadata) as a pointer to the content itself, so no one can dispute what your NFT is.
Filecoin provides long-term storage for the data ensuring that even if NFT.Storage is attacked or taken down the NFT data persists! This storage is trustlessly verifiable (with on-chain, cryptographic proofs that data is stored as promised). And NFT.Storage will continue to decentralize itself out of the picture moving forward (e.g., making perpetual storage completely smart contract-based utilizing future tools like the Filecoin Virtual Machine).
Have additional preferences on where to store your data? Pin your data to any storage solution running a pinning service.
#Retrieve
NFT data stored by NFT.Storage can be accessed from the decentralized IPFS network from any peer that has the content. CIDs reference immutable content so you can be sure the content you access is the content referenced in the NFT.
The data can be fetched directly in the browser using Brave, or via a public IPFS gateway, or by using IPFS Desktop or the IPFS command line.
If fetching content using a public IPFS gateway (e.g., directly using an HTTP URL or via Brave), note that the availability and speed of retrieving the content depends on the gateway. In cases where the gateway is unable to retrieve a given CID (e.g., returns a 429 error), you can try a different gateway or running and using your own IPFS node instead.
