CONVERT
ZIP → ZST

Yes. The free tier accepts files up to 100 MB without registration, email capture or watermarks. Paid plans raise the size cap, enable batch conversions and provide a REST API for automation, but nothing on the free tier is quality-limited — the output is exactly the same as on any paid plan.

Yes — because ZIP and ZST use different compression codecs, every entry is decompressed from the ZIP and re-compressed for the ZST. The uncompressed data is identical on both sides, and the re-compression happens entirely inside our processing container.

Uploads run over HTTPS, files are processed in isolated containers, and both the source ZIP and the ZST output are auto-deleted within two hours. No account is required, file contents are never logged, and KaijuConverter does not use uploads for AI training. The paid plan adds a signable data-processing agreement for regulated workflows.

Usually yes, modestly, when the original ZIP used an older codec like Deflate. Against modern LZMA2 / Zstd ZST containers expect 10-30% savings on mixed content and almost no change on pre-compressed payloads. Advanced → compression level lets you trade speed for ratio.

Most files finish in well under a minute. Small images and documents are typically ready in a few seconds; large video or audio files scale roughly with duration. Upload speed from your network is usually the dominant factor, not server time.

Yes. Provide the password during upload; we use it only to decrypt inside the processing container and never log or persist it. The resulting ZST can be re-encrypted with a password of your choice (AES where the target format supports it).