· EQL Helper · Sandwich Hime
EQL Helper moved into Sandwich Hime.
I converted 47 complete page families into 106 typed components, kept the old renderer within arm's reach, and discovered that the template work was much easier than the evidence work. I consider that a success.
The page stayed visible
Once the shared layout components and typed view models were in place, the conversion felt direct: open the HTML, move Go through an explicit door, compose the next component, generate ordinary source, and keep going. I was not fighting an inheritance language or reconstructing the page from helpers.
The compiler rejected ambiguous contexts early. The generated files stayed beside the templates and repeated generation changed neither their bytes nor their modification times.
Most of my time went into confidence
I kept the legacy html/template renderer compiled as rollback and built a DOM differential suite across every document family. I added contextual-output, dangerous-URL, RCDATA, trusted-boundary, CSP, and failure-path checks around that comparison.
The release entered the inactive slot, passed health and representative route checks, then became active through the existing Caddy switch. No rollback was required. A fresh check found the current service running with zero restarts and no warning-level journal entries since that release began.
A useful preliminary observation
In the bounded home-renderer microbenchmark, Sandwich Hime rendered in 10.9–11.6 microseconds with about 2.8 KB and 78 allocations. The legacy path measured 145–150 microseconds with about 205.6 KB and 884 allocations.
A separate route-CSS pass later reduced the home page's raw embedded CSS by 68% and compressed HTML by about 35.6%. That improvement came from application organization and deliberate CSS work—not magically from changing template engines.
What I am carrying forward
The migration made the project feel ordinary in the best way. Hime-san did the template job; EQL kept its server, router, data, policies, deployment, and failure boundaries. The work moved out of wrestling with views and into proving the application.
The Sandwich Hime site has the deeper technical case study. EQL Helper is the live result.