One archive.
Every advantage.
SQZ deduplicates repeated data, routes content to the right codec, and understands what is inside your files. Less waste, by design.
See how it works → SQZ Atlas · archiver v0.9.1 · backup planned
Make room
for more.
SQZ packs folders into one small archive. It skips data it has already stored, sorts what is left so it squeezes better, and checks every file when you restore it.
10 screenshots · PNG MEASURED
Size left after packing, as a share of the original
MEASURED ONWindows
DURINGv0.3 – v0.4
SAVED53.2%
BLAKE3 ✓
DEDUPLICATED ↗
DUPLICATES STORED ONCE✦STREAMING BY DEFAULT✦EVERY BYTE VERIFIED✦DUPLICATES STORED ONCE✦STREAMING BY DEFAULT
01 / The difference
Compression without
compromise.
One archive.
01
Stream it
Pack and extract data larger than your RAM. Memory use depends on block size and threads, not on how much you pack.
02
Trust it
Every restored file is checked with BLAKE3 before it is published. Existing files are never overwritten.
03
Keep it
Append snapshots over time. Restore any of them, or just one file, without storing unchanged data twice.
02 / How it works
Six steps from
folder to archive.
You run one command. Behind it, every file takes the same trip, and every step can be undone exactly.
- 01
Sort
Files are scanned and lined up by type, so similar files sit next to each other.
- 02
Unpack
Already-compressed PNG, ZIP, Office, PDF, gzip and JPEG files are opened up, but only if SQZ can rebuild the original bytes exactly.
- 03
Chunk
Data is cut into pieces at points chosen by the content itself, so a small edit only changes nearby pieces.
- 04
Skip repeats
Each piece gets a BLAKE3 fingerprint. A piece that is already stored is kept once and simply pointed to.
- 05
Group
Pieces are routed into text, program, binary, raw or image groups, because like compresses best with like.
- 06
Squeeze & seal
Each group is compressed with the codec your mode picks, in parallel, and the archive index is sealed with a BLAKE3 tag.
03 / Snapshots
Back up daily.
Store changes only.
Add a new snapshot with sqz a. Pieces that did not change are pointed to, not stored again.
Monday
ABCD
Tuesdayone file edited
ABC′D
Stored in the archive
ABCDC′
5 pieces, not 8 Stored piece Pointer to a piece already stored
Illustration. The same idea applies inside a single backup: an image embedded in two documents, or many versions of one file, is stored once. Every snapshot stays restorable, and sqz x -s 1 brings back snapshot 1.
04 / Pick your pace
There’s a mode
for that.
Faster modes finish sooner. Slower modes spend more time looking for a smaller result.
MODEWHAT IT USESIDEAL FORSTATUS
--maxSQZ’s own context-mixing engine or LZMA2, picked by sample, checked against zstdLong-term archivesDEFAULT
--balancedThe smaller of LZMA2 or zstd, plus photo and document unpackingEveryday compressionAVAILABLE
--fastzstd, without photo and document unpackingQuick packing & transferAVAILABLE
Same 591 KB log file, three modes Archive size Time to pack
--fast
--balanced
--max
Median of three runs on a generated 10,000-line log file (Linux, 8 CPUs). Max also takes longer to unpack. It picks codecs from samples, so it is not guaranteed to beat balanced on every input.
05 / Side by side
How it stacks
up.
Shorter bar means a smaller archive. Every result below was restored and checked byte for byte.
Log file
Repetitive text, 591 KB
Photos & files
JPEG, PNG and ZIP, 43.7 KB
Random data
Already unpredictable, 524 KB
Random bytes cannot be shrunk by any tool. SQZ adds under 0.1% of overhead here.
Bars are scaled within each chart. Small generated test inputs from SQZ’s benchmark lab: median of three runs after one warmup, 140 verified round trips, 0 failures. They check the pipeline and are not a claim about your own folders.
The engine inside --max
SQZ’s own context-mixing engine against xz -9e, the LZMA2 maximum setting 7-Zip Ultra uses.
Python source, 2 MB
−18%
CSV sales data, 5 MB
−30%
Program code, 4 MB
−15%
Linux tools, 6 MB
−15%
ELF symbol table, 8 MB
tie
4 screenshot PNGs, unpacked
−24%
From the engine notes in SQZ’s architecture document. The engine runs at about 0.5 MB/s per thread and uses about 260 MB at level 6, so max mode trades speed for size.
06 / SQZ Atlas
Store once. Preserve everything.
Recover anything.
Atlas is the plan for two products on one shared, lossless storage layer: the archive you can use today, and a backup tool that is on the way.
Input
Your files
Folders, documents, photos, builds, model checkpoints
Shared layer
One lossless core
- Exact deduplication
- Reversible unpacking of PNG, ZIP, PDF, JPEG
- Codec picked per block
- BLAKE3 checks on every restore
AVAILABLE · v0.9.1
SQZ Archive
A portable .sqz file for everyday packing, sharing and snapshots.
PLANNED
SQZ Backup
An encrypted, incremental backup repository, kept separate from the .sqz format.
Coming next
SQZ Backup: what is planned
SQZ Backup is not built yet. The roadmap describes what it should do, and nothing below is a shipped feature.
- EncryptedAuthenticated encryption from a reviewed library, with key recovery. No home-made cipher.
- IncrementalEach snapshot stores only new data. A snapshot appears only once everything it needs is safely written.
- Retention & pruningKeep the snapshots you want and safely reclaim the space of the rest.
- Verify & restoreIntegrity checks, search, and restore of one file or everything, with the latest verified snapshot shown clearly.
- Local, then cloudLocal storage first, then S3-compatible storage with resumable uploads.
- Windows awarePlanned VSS support for consistent copies of open files, and faster change detection.
- 0
Baseline
Reproducible benchmarks and frozen test fixtures
In progress - 1
Atlas core
Verified chunk identities, format spec, codec registry
In progress - 2
Archive product
Safe extraction, full metadata, ZIP export, everyday UI
In progress - 3
Backup foundation
Encrypted repository, snapshots, retention, prune, then S3
Not started - 4
Smarter storage
Similarity deltas, hot and cold compaction, recovery drills
Early work - 5
Research
Lighter and stronger engines, new transforms, neural tests
Not started
From the SQZ Atlas strategy in the sqz-next repository, status as of 0.9.1. It is a proposed roadmap with no dates, and each stage ships only when its correctness, restore and benchmark checks pass.
07 / Good to know
Honest about
the limits.
Not stored yet
Empty folders, file permissions and symlinks. Names that are not valid UTF-8 are converted.
No encryption yet
Archives are checked for corruption but are not encrypted. Encryption and pruning old snapshots are planned for SQZ Backup.
Restores go somewhere new
Extract into a new, empty folder. SQZ never overwrites existing files, and the drive must support hard links.
Format v5
New archives need SQZ 0.9.1 or later to open. Archives from v1 to v4 can still be read.
08 / Ready when you are
Start squeezing.
Build from source with Rust 1.85+ and a C++17 compiler.
$ git clone https://github.com/hankitools/sqz-next
$ cd sqz-next
$ cargo build --locked --release
✓ target/release/sqz readysqz c photos photos.sqzCreate an archive from a foldersqz x photos.sqz restoredExtract it into a new foldersqz t photos.sqzTest that every file restoressqz a photos photos.sqzAdd a new snapshot