Nix Cache Info Format
The nix-cache-info file is a metadata file at the root of a binary cache (e.g., https://cache.example.com/nix-cache-info).
MIME type: text/x-nix-cache-info
Format
Line-based key-value format:
Key: value
Leading and trailing whitespace is trimmed from values. Lines without a colon are ignored. Unknown keys are silently ignored.
Fields
StoreDir
The Nix store directory path that this cache was built for (e.g., /nix/store).
If present, Nix verifies that this matches the client's store directory:
error: binary cache 'https://example.com' is for Nix stores with prefix '/nix/store', not '/home/user/nix/store'
WantMassQuery
1 or 0. Sets the default for want-mass-query.
Priority
Integer. Sets the default for priority.
Example
StoreDir: /nix/store
WantMassQuery: 1
Priority: 30
Caching Behavior
Nix caches nix-cache-info in the cache directory with a 7-day TTL.