What changed in Swiper from 12 to 14

Bug Fixes

• cards: prevent invalid calc() transform with low perSlideOffset (d8ff235), closes #8211
• core: do not emit index-change events from loopFix teleports (#8015) (9b78f71)
• core: harden extend() against prototype-method override in key filtering (93154fc), closes #8189
• core: recompute rtlTranslate in changeDirection (#8053) (b4b49bf)
• core: size loop buffer from actual offset width, not centeredSlides geometry (#8203) (bc4a658)

Features

• core: add lazyPreload param to disable built-in lazy image handling (#7570) (81345db)
• fade: add fadeEffect "mode" param with new "out-in" transition mode (#8051) (b907702)

Bug Fixes

• core: keep module defaults when params come from another realm (4bb6caf)
• core: make elementOffset viewport-relative again (1115f9e), closes #8209
• types: preserve module options in breakpoints (d598495), closes #8207

Bug Fixes

• zoom: zoom to the tapped point on the first double-tap (e0d4ed5)

Bug Fixes

• virtual: render first slide on initial update (ebdb054), closes #8202

Bug Fixes

• build: spawn npx via shell on Windows in emit-types (494f7b1), closes #8197
• pagination: divide fraction/progressbar total by grid rows (edfbfa5)
• react: bind Thumbs tap handler when thumbs swiper is set after init (4fb72b9), closes #8198

Patch release fixing two web-component (and Vue wrapper) regressions introduced by the v14 rewrite.

Bug Fixes

• core: restore slide detection in web component — the <swiper-container> element initialized with zero slides because slidesEl was resolved to the shadow root instead of the host element (b3b822f), closes #8196
• element: render navigation/pagination/scrollbar when set as boolean params — bare boolean usage (<swiper-container navigation>, Vue :navigation="true") stopped rendering the built-in controls (253fa39), closes #8196

Swiper v14 is a ground-up TypeScript rewrite of the entire codebase, focused on smaller bundles, more accurate types, and a modern browser baseline. (We skipped v13.)

Upgrading from v12 requires no code changes. Every option, default, event, payload, method signature, and module import (swiper/modules, swiper/react, swiper/vue, swiper/element, …) behaves exactly as before. The only differences you may notice are tighter TypeScript types and a narrower set of supported browsers — see Breaking Changes below.

Highlights

• Single TypeScript source of truth. src/ is now .ts/.tsx. The hand-maintained .d.ts tree (src/types/, the per-module .d.ts files) is gone — declarations are emitted directly from the runtime source with tsc, so the shipped types can no longer drift from the implementation. Several signatures that used to be any are now correctly typed (e.g. getTranslate(): number).
• Per-module type augmentation. Each module augments the central Swiper / SwiperOptions / SwiperEvents interfaces. Importing a module (e.g. import { Navigation } from 'swiper/modules') brings its option, method, and event types along with it — mirroring how the runtime already requires registration.
• More reliable type resolution. Types now resolve correctly under classic node, node16/nodenext, and bundler module resolution, and swiper/bundle exposes every module's options out of the box. Verified by a consumer-simulation test suite.
• Zero runtime dependencies. The ssr-window dependency was removed and replaced with inline environment guards. Swiper now installs with no transitive runtime deps.
• Smaller minified bundles. Legacy DOM-compat helpers and below-baseline feature detection were removed. The shared DOM utils shrank ~28%, and the main builds are ~2–4% smaller minified (swiper.min.js −4.1%, swiper-element.min.js −2.9%, swiper-bundle.min.js −2.3%).
• Babel removed from the build. TypeScript now handles the JSX transform for the React wrapper, and @babel/preset-env is a no-op at the v14 baseline. Runtime output is byte-identical (React output is marginally smaller).

Breaking Changes

• Browser baseline raised to the last ~2 years of evergreen browsers. Swiper v14 targets Chrome / Edge 110+, Safari 16.4+ (iOS 16.4+), and Firefox 110+. Code paths and feature detection for older browsers were removed (e.g. the smoothScroll support flag, the Safari < 16.2 perspective workaround, and the legacy DocumentTouch touch check). iOS/Android-specific quirk handling is kept but simplified. If you need to support older browsers, stay on v12.
• Node.js >= 20.19.0 is now required to build/develop against the package (engines was >= 4.7.0). This does not affect the browser runtime.
• Type-level changes. Stricter types may surface latent issues in code that previously relied on any-typed access to Swiper internals. These are compile-time only — there are no runtime behavior changes.

SSR

ssr-window's mock window/document were replaced with inline typeof guards. Server rendering with the React / Vue / Element wrappers is unaffected — they only instantiate Swiper in client-side mount effects. Imperatively calling new Swiper(...) in a pure Node (non-DOM) environment once again no-ops gracefully, matching v12 behavior, and is now locked down by a dedicated SSR runtime test.