diff --git a/.github/workflows/deploy.yml b/.github/workflows/deploy.yml
index c1fedb6..a75b867 100644
--- a/.github/workflows/deploy.yml
+++ b/.github/workflows/deploy.yml
@@ -3,6 +3,13 @@ name: Deploy to GitHub Pages
 on:
   push:
     branches: [main]
+    # README-only and workflow-only edits don't change anything the app
+    # serves, so skip them: a redeploy would still bake a new commit hash
+    # into the PWA build and force the "update available" prompt on every
+    # visitor for no user-facing reason.
+    paths-ignore:
+      - 'README.md'
+      - '.github/**'
   workflow_dispatch:
 
 permissions:
diff --git a/LICENSE b/LICENSE
new file mode 100644
index 0000000..cd3fc28
--- /dev/null
+++ b/LICENSE
@@ -0,0 +1,27 @@
+MIT License
+
+Copyright (c) 2026 dubsector
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
+
+---
+
+This license covers video-shrinker's own source code. The optional CPU-fallback
+encoder it loads at runtime bundles third-party FFmpeg code under different,
+copyleft terms — see the "Third-party licenses" section of README.md.
diff --git a/README.md b/README.md
index 678f658..8867508 100644
--- a/README.md
+++ b/README.md
@@ -23,6 +23,23 @@ It's installable as an app. An in-page banner offers to install it directly, or
 - [vite-plugin-pwa](https://vite-pwa-org.netlify.app/) for the installable/offline bits
 - React + Vite, deployed to GitHub Pages via Actions
 
+## License
+
+video-shrinker's own source is [MIT](LICENSE).
+
+The CPU-fallback encoder (`@ffmpeg/core`, only loaded when a browser can't do
+WebCodecs hardware encoding) is a separately-distributed FFmpeg build compiled
+with `--enable-gpl --enable-libx264 --enable-libx265`, which makes that binary
+**GPL-2.0-or-later**, not MIT/LGPL. It's self-hosted from this repo as a static
+asset. Its corresponding source is the upstream project at the exact version
+in use: [ffmpegwasm/ffmpeg.wasm @ v0.12.10](https://github.com/ffmpegwasm/ffmpeg.wasm/tree/v0.12.10)
+([build config](https://github.com/ffmpegwasm/ffmpeg.wasm/blob/v0.12.10/Dockerfile)).
+
+Everything else shipped to the browser is permissive: React and React-DOM
+(MIT), `@ffmpeg/ffmpeg`'s JS wrapper and `@ffmpeg/types` (MIT), and Mediabunny
+(MPL-2.0). Build-only tooling (Vite, TypeScript, oxlint, the PWA/static-copy
+plugins) isn't distributed with the app and isn't covered here.
+
 ## Development
 
 ```