Ha.mr, built by PortalRunner, compresses URLs instead of shortening them. No third-party database. No opaque redirects. The full algorithm is open source on GitHub, meaning you can verify where a link goes before you click it, and self-host the entire service if you need reliability guarantees.
The QR code optimization is the technically interesting part. QR codes have a native alphanumeric mode with a restricted character set. Feed them arbitrary UTF-8 and you drop into byte mode, which consumes significantly more QR real estate for the same data. Ha.mr's compressed output is shaped to stay in the efficient character set, producing smaller, easier-to-scan codes at equivalent size. The full write-up explains exactly how the encoding and compression pipeline achieves this.
PortalRunner built this as a side project and makes no uptime promises, so self-hosting is the practical path for serious use. The project currently uses conventional compression algorithms. For anyone who wants to push further, the article links to a 2023 Hackaday piece on LLM-based text compression that gets into genuinely strange efficiency territory.
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