Export / Import

R.EXPORT serializes a bitmap to the CRoaring portable format — the interchange standard implemented by every major Roaring library — and R.IMPORT reads it back, OR-merging into the destination key. This is the module's signature capability: a compressed set leaves Valkey as a small binary blob and deserializes natively anywhere.

Valkey (R.EXPORT)  →  binary blob  →  Java / Go / Python / C++ / Rust service

For sparse or clustered sets the blob is typically 10–40× smaller than the equivalent integer array, and the receiving side pays no parsing cost.

From a shell

valkey-cli's raw output and -x flag are binary-safe:

valkey-cli R.EXPORT source > bitmap.bin          # raw reply → file
valkey-cli -x R.IMPORT destination < bitmap.bin  # stdin → last argument

Raw binary can't be pasted as a command argument, but its Base64 text can. Add BASE64 to either command:

$ valkey-cli R.EXPORT users:active BASE64
"OjAAAAEAAAAAAAEAEAAAACoAZAA="
$ valkey-cli R.IMPORT users:copy OjAAAAEAAAAAAAEAEAAAACoAZAA= BASE64
(integer) 2

# or in one step
valkey-cli R.IMPORT destination "$(valkey-cli R.EXPORT source BASE64)" BASE64

The text is standard Base64 (RFC 4648 alphabet, = padding), so base64 -d or any language's decoder turns it back into the blob:

valkey-cli R.EXPORT source BASE64 | base64 -d > bitmap.bin

From Lua

local data = redis.call('R.EXPORT', 'source')
redis.call('R.IMPORT', 'destination', data)

From Python (pyroaring)

from pyroaring import BitMap
import valkey

client = valkey.Valkey()
blob = client.execute_command("R.EXPORT", "users:active")
bm = BitMap.deserialize(blob)          # a real CRoaring bitmap

bm.add(999)
client.execute_command("R.IMPORT", "users:active", BitMap.serialize(bm))

The 64-bit variant round-trips the same way with BitMap64, including values above 2⁶³.

Compatible libraries

Language	Library
Java	RoaringBitmap
Go	roaring
Python	pyroaring
C/C++	CRoaring
Rust	roaring-rs

Byte-compatibility in both directions and both widths is verified against CRoaring itself as part of the project's validation suite.

Semantics worth knowing

• R.IMPORT OR-merges into an existing key (and creates it when missing); it replies with the cardinality after the merge.
• R.EXPORT optimizes container storage before serializing, so exported blobs are as small as the data allows. They are also canonical: one set always exports the same bytes, and the same Base64 text.
• Malformed input to R.IMPORT is rejected with an error — the deserialization path is fuzz-tested against corrupted, truncated, and garbage bytes.
• Base64 text is decoded strictly: no whitespace or line breaks, no URL-safe alphabet, padding required. Text that is not exactly what R.EXPORT ... BASE64 would produce for some blob is rejected with ERR bad binary data for roaring.
• An R.IMPORT ... BASE64 replicates and reaches the AOF exactly as sent, and replays the same way.