Htmx 4.0 migration, paste it.
Convert your Htmx 3.x code to 4.0-compatible syntax. Covers all breaking changes. No docs required.
Why Htmx 4.0 migration matters right now
The Htmx 4.0 release hit Hacker News with 562 upvotes and 138 comments in a single day — a clear signal that the community is both excited and anxious. The two-year gap between 3.x and 4.0 means a mountain of legacy code exists in production. Developers who maintain multiple Htmx projects are now facing a deterministic migration burden: breaking changes in hx-trigger events, hx-swap-oob syntax removal, and altered default targets. Reading the official changelog is time-consuming; each project requires careful manual review.
Existing solutions fall short. The official migration guide is a reference document, not a tool — you still have to grep through your codebase and apply changes by hand. AI assistants like ChatGPT produce plausible but unreliable output, forcing you to verify every line. Neither approach scales for a freelancer juggling five client projects. The pain is real: one HN commenter admitted "the upgrade cost me an entire afternoon." That's a $100+ opportunity cost for a solo dev.
Now is the perfect moment. The 4.0 discussion is at its peak across HN, Lobsters, and r/htmx — the exact audience that needs this tool is actively searching for solutions. A deterministic, rule-based converter that runs entirely in the browser can turn a 3-hour migration into a 30-second paste. No AI uncertainty, no documentation deep-dives. Just paste, convert, and ship.
How It Works
Paste your 3.x code
Copy any HTML snippet that uses Htmx 3.x attributes — hx-get, hx-trigger, hx-swap-oob — and drop it into the converter. No signup, no upload, everything stays in your browser.
Instant deterministic conversion
Our rule engine applies the complete list of 4.0 breaking changes: event renames like revealed → intersect, hx-swap-oob syntax updates, and default target adjustments. Every transformation is 100% predictable.
Copy & verify
Get your 4.0-compatible code instantly, with manual-edit flags for any ambiguous cases. You keep full control — the tool highlights exactly what changed, so you can review and ship with confidence.
What You Get
100% deterministic
Unlike AI-based tools that hallucinate, our rule engine follows the official 4.0 changelog exactly. Every conversion is reproducible and predictable — you get the same output every time, with zero guesswork.
Covers all breaking changes
From hx-trigger event renames to the deprecated hx-swap-oob syntax, we've mapped every single change listed in the official 4.0 migration notes. No more grepping through docs or missing edge cases.
Zero learning curve
Paste your HTML, get the converted version in under 30 seconds. No installation, no CLI, no configuration. It's the fastest way to migrate multiple projects without touching the docs.