What's the maximum size of a Node.js Buffer

Maximum length of a typed array in V8 is currently set to kSmiMaxValue which depending on the platform is either:

• 1Gb - 1byte on 32-bit
• 2Gb - 1byte on 64-bit

Relevant constant in the code is v8::internal::JSTypedArray::kMaxLength (source).

V8 team is working on increasing this even further on 64-bit platforms, where currently ArrayBuffer objects can be up to Number.MAX_SAFE_INTEGER large (2**53 - 1). See bug 4153.

This is now documented as part of Node's buffer api, the maximum size is buffer.constants.MAX_LENGTH.

buffer.constants.MAX_LENGTH <integer> The largest size allowed for a single Buffer instance.

• On 32-bit architectures, this value is (2^30)-1 (~1GB).
• On 64-bit architectures, this value is (2^31)-1 (~2GB).

This value is also available as buffer.kMaxLength.

So you can figure out how big it is by doing

> (require('buffer').constants.MAX_LENGTH + 1) / 2**30
2