Nintendo Switch File Types Explained: NSP, XCI, NSZ and XCZ

If you have spent any time reading about Switch software you will have run into four extensions — NSP, XCI, NSZ and XCZ — usually with no explanation of what separates them. They are not interchangeable, and the differences matter.

NSP — the digital container

NSP stands for Nintendo Submission Package. It is the container format the eShop uses to distribute digital content: base games, updates and DLC all ship as NSP files. An NSP is a PFS0 archive holding the content files plus a ticket and certificate that control decryption.

Because it is the digital distribution format, an NSP contains only what the eShop would send you. It has no cartridge metadata, because no cartridge was involved.

XCI — the cartridge image

XCI stands for NX Card Image. It is a dump of a physical game card, including the cartridge header, the partition layout and the secure area. An XCI is therefore structurally different from an NSP of the same game, and larger, because it preserves the cartridge’s own structure.

A practical consequence: tools that work with one format often will not accept the other without conversion, and “trimmed” XCI files have had the unused padding at the end of the cartridge image removed to save space.

NSZ and XCZ — the compressed variants

NSZ and XCZ are compressed forms of NSP and XCI, using zstandard. The compression is applied to the content archives inside the container rather than to the container as a whole, which keeps the structure readable. Savings vary widely by game — titles with large amounts of uncompressed audio or texture data shrink considerably, while already-compressed content barely moves.

These are community formats rather than official Nintendo ones, and they need decompressing before anything can read them normally.

Reading a Title ID

Every Switch application carries a 16-character hexadecimal Title ID. Super Mario Odyssey’s is 0100000000010000. The structure is predictable: base games end in 000, their update packages end in 800, and DLC uses a related range above the base ID.

That predictability is what makes Title IDs useful as identifiers. A game’s name varies by region and by how a listing was written; its Title ID does not. Every game page on NSWPEDIA lists the Title ID alongside the Build ID, which unlike the Title ID does change with each update, making the pair a precise way to identify exactly which revision you are looking at.

A note on where files come from

NSWPEDIA documents these formats as reference material. We do not host or link to copyrighted game files — our downloads section is limited to homebrew and public-domain software whose licences permit redistribution.