Week 13 building Convertify in public: the unglamorous debt week

Convertify is a free image converter (HEIC/WebP/AVIF/JPG and 20+ formats), built solo on Rust + Axum + libvips with a Next.js frontend. Week 13 of a 52 week build-in-public series.

This was a debt week, and I think those are worth writing about honestly because the build-in-public timeline is usually all launches and wins.

What actually happened:

1. Chased a production segfault to its root cause.
   My "images to PDF" path was crashing intermittently with a GObject assertion failure. Turned out a derived Clone on the libvips image type was doing a bitwise pointer copy without taking a reference, so two Rust values owned one C object and Drop freed it twice. One line fix (ops::copy instead of .clone()), a couple evenings to be sure it was that line. Wrote it up as a dev.to article.
   Fixed a real UX dead-end.

2. If you went over the 20 MB limit, the convert button disabled itself but there was no way to recover except guessing. Added a proper file list where you can remove individual files, a size-limit toast, and a clear over-limit state. Small, but it was quietly losing people.

3. Audited my own content for honesty. I went through landing pages removing claims that did not match the actual backend behavior (metadata handling, compression details). I would rather say less and be correct than pad pages with things that are not true. This also turns out to be what differentiates the site from templated competitors.

4. Closed some SEO loops. Linked my HEIC blog cluster together properly, shipped a weekly dev.to post, and did a backlink audit that showed my real ceiling: almost all my external links point at the homepage, and my tool pages have near zero authority. That is the thing to fix next.

What I learned: the highest-leverage growth move I have is not another guest post, it is turning my actual benchmark data (real Rust + libvips measurements on real images) into a public study people can cite. That is the plan for the technical weeks ahead.

Next week is a dedicated technical week: backend features, a refactor of my upload handler, and that benchmark asset.

If you are building something image-heavy or just want to poke at it: convertifyapp.net. No account, files get deleted after 6 hours conversion.