diff --git a/.github/scripts/install-ndi-linux.sh b/.github/scripts/install-ndi-linux.sh
new file mode 100755
index 0000000..a99b015
--- /dev/null
+++ b/.github/scripts/install-ndi-linux.sh
@@ -0,0 +1,82 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+if [[ -z "${NDI_SDK_URL_LINUX:-}" ]]; then
+  echo "NDI_SDK_URL_LINUX is not set" >&2
+  exit 1
+fi
+
+archive="$RUNNER_TEMP/ndi-sdk-linux"
+extract_dir="$RUNNER_TEMP/ndi-sdk-linux-extract"
+mkdir -p "$extract_dir"
+
+curl -L --retry 3 --retry-delay 5 "$NDI_SDK_URL_LINUX" -o "$archive"
+
+if file "$archive" | grep -qi 'gzip compressed'; then
+  tar -xzf "$archive" -C "$extract_dir"
+elif file "$archive" | grep -qi 'bzip2 compressed'; then
+  tar -xjf "$archive" -C "$extract_dir"
+elif file "$archive" | grep -qi 'Zip archive'; then
+  unzip -q "$archive" -d "$extract_dir"
+else
+  chmod +x "$archive"
+  (cd "$extract_dir" && printf 'y\ny\n' | "$archive")
+fi
+
+# NDI's Linux download is a .tar.gz containing a self-extracting shell installer.
+# Run it non-interactively after unpacking the outer archive.
+installer="$(find "$extract_dir" -maxdepth 2 -type f -name 'Install_NDI_SDK*_Linux*.sh' -print -quit || true)"
+existing_header="$(find "$extract_dir" -type f -path '*/include/Processing.NDI.Lib.h' -print -quit || true)"
+if [[ -n "$installer" && -z "$existing_header" ]]; then
+  chmod +x "$installer"
+  (cd "$(dirname "$installer")" && printf 'y\ny\n' | PAGER=cat ./"$(basename "$installer")")
+fi
+
+sdk_root=""
+while IFS= read -r header; do
+  candidate="$(dirname "$(dirname "$header")")"
+  first_lib="$(find "$candidate" -type f -name 'libndi.so*' -print -quit || true)"
+  if [[ -n "$first_lib" ]]; then
+    sdk_root="$candidate"
+    break
+  fi
+done < <(find "$extract_dir" /usr/local /opt -type f -path '*/include/Processing.NDI.Lib.h' 2>/dev/null || true)
+
+if [[ -z "$sdk_root" ]]; then
+  echo "Could not locate Processing.NDI.Lib.h and libndi.so after extracting Linux NDI SDK" >&2
+  find "$extract_dir" -maxdepth 4 -type f | sort >&2 || true
+  exit 1
+fi
+
+# Normalize into the project-local layout CMake searches first. Preserve symlinks
+# so versioned libndi.so chains remain intact.
+case "$(uname -m)" in
+  x86_64|amd64) ndi_arch_dir="x86_64-linux-gnu" ;;
+  aarch64|arm64) ndi_arch_dir="aarch64-rpi4-linux-gnueabi" ;;
+  armv7l) ndi_arch_dir="arm-rpi4-linux-gnueabihf" ;;
+  *) ndi_arch_dir="" ;;
+esac
+
+lib_source_dir=""
+if [[ -n "$ndi_arch_dir" && -d "$sdk_root/lib/$ndi_arch_dir" ]]; then
+  lib_source_dir="$sdk_root/lib/$ndi_arch_dir"
+elif [[ -d "$sdk_root/lib" ]]; then
+  lib_source_dir="$sdk_root/lib"
+fi
+
+rm -rf ndi
+mkdir -p ndi/include ndi/lib
+cp -a "$sdk_root/include"/. ndi/include/
+if [[ -z "$lib_source_dir" ]]; then
+  echo "Could not locate an NDI library directory for $(uname -m) under $sdk_root/lib" >&2
+  exit 1
+fi
+cp -a "$lib_source_dir"/libndi.so* ndi/lib/
+
+if [[ ! -e ndi/lib/libndi.so ]]; then
+  first_lib="$(find ndi/lib -type f -name 'libndi.so*' | sort | head -n1)"
+  [[ -n "$first_lib" ]] || { echo "No libndi.so found in normalized SDK" >&2; exit 1; }
+  ln -s "$(basename "$first_lib")" ndi/lib/libndi.so
+fi
+
+echo "NDI SDK normalized to $PWD/ndi"
diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 1468b2e..88c6982 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -4,6 +4,8 @@ on:
   push:
     branches: ["**"]
     tags: ["v*"]
+  pull_request:
+    branches: ["**"]
   workflow_dispatch:
     inputs:
       tag:
@@ -265,11 +267,198 @@ jobs:
           path: OnPoint-*-Setup.exe
           if-no-files-found: error
 
+  # ─────────────────────────────────────────────────────────────────────────────
+  build-linux:
+    name: Linux x64
+    runs-on: ubuntu-22.04
+
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          ref: ${{ github.event_name == 'workflow_dispatch' && github.event.inputs.tag || github.ref }}
+
+      - name: Install system dependencies
+        run: |
+          sudo apt-get update
+          sudo apt-get install -y --no-install-recommends \
+            build-essential \
+            ninja-build \
+            curl \
+            file \
+            unzip \
+            libgl1-mesa-dev \
+            libxkbcommon-dev \
+            libxcb-cursor0 \
+            libxcb-cursor-dev \
+            libopencv-dev \
+            libavahi-compat-libdnssd-dev
+
+      - name: Install Qt
+        uses: jurplel/install-qt-action@v4
+        with:
+          version: "6.8.3"
+          host: linux
+          target: desktop
+          arch: linux_gcc_64
+          modules: "qtmultimedia"
+          cache: true
+
+      - name: Install NDI SDK
+        env:
+          NDI_SDK_URL_LINUX: ${{ secrets.NDI_SDK_URL_LINUX }}
+        run: bash .github/scripts/install-ndi-linux.sh
+
+      - name: Configure
+        run: |
+          cmake -S . -B build -G Ninja \
+            -DCMAKE_BUILD_TYPE=Release \
+            -DCMAKE_PREFIX_PATH="$QT_ROOT_DIR" \
+            -DCMAKE_INSTALL_PREFIX="$PWD/package/OnPoint-Linux-x86_64"
+
+      - name: Build
+        run: cmake --build build --parallel $(nproc)
+
+      - name: Package
+        run: |
+          set -euo pipefail
+
+          appdir="$PWD/package/OnPoint-Linux-x86_64"
+          mkdir -p "$appdir/bin" "$appdir/lib" "$appdir/plugins" "$appdir/share/doc/onpoint"
+
+          cp build/onpoint "$appdir/bin/"
+          cp -a ndi/lib/libndi.so* "$appdir/lib/"
+          cp README.md "$appdir/share/doc/onpoint/" 2>/dev/null || true
+
+          # Bundle Qt from the aqt installation.  The Linux artifact is built
+          # against Qt 6.8 from QT_ROOT_DIR, which is not available on a clean
+          # Ubuntu install, so the launcher must not depend on system Qt.
+          cp -aL "$QT_ROOT_DIR/lib"/libQt6*.so* "$appdir/lib/"
+
+          for plugin_dir in \
+            platforms \
+            platformthemes \
+            imageformats \
+            iconengines \
+            tls \
+            xcbglintegrations \
+            multimedia; do
+            if [ -d "$QT_ROOT_DIR/plugins/$plugin_dir" ]; then
+              cp -a "$QT_ROOT_DIR/plugins/$plugin_dir" "$appdir/plugins/"
+            fi
+          done
+
+          cat > "$appdir/bin/qt.conf" <<'EOF'
+          [Paths]
+          Prefix = ..
+          Plugins = plugins
+          EOF
+
+          should_bundle() {
+            local lib="$1"
+            local soname
+            soname="$(basename "$lib")"
+
+            # Do not bundle glibc/loader primitives; they must come from the
+            # target system.  Bundle the rest of the runtime closure so the
+            # archive works on minimal Ubuntu installs that may not have GLX,
+            # OpenCV, TBB, PulseAudio, or Qt plugin dependencies preinstalled.
+            case "$soname" in
+              libc.so.*|ld-linux-x86-64.so.*|libpthread.so.*|libdl.so.*|librt.so.*|libm.so.*|libresolv.so.*)
+                return 1
+                ;;
+            esac
+
+            case "$lib" in
+              "$appdir"/*|"$QT_ROOT_DIR"/*|"$PWD"/ndi/*|/usr/lib/*|/lib/*)
+                return 0
+                ;;
+              *)
+                return 1
+                ;;
+            esac
+          }
+
+          copy_deps() {
+            local target="$1"
+            ldd "$target" \
+              | awk '/=> \/.*\.so/ {print $3} /^\s*\/.*\.so/ {print $1}' \
+              | while IFS= read -r lib; do
+                  [ -f "$lib" ] || continue
+                  case "$lib" in
+                    "$appdir"/*)
+                      continue
+                      ;;
+                  esac
+                  if should_bundle "$lib"; then
+                    cp -aL "$lib" "$appdir/lib/"
+                  fi
+                done
+          }
+
+          copy_deps build/onpoint
+          find "$appdir/plugins" -type f -name '*.so' -print0 | while IFS= read -r -d '' plugin; do
+            copy_deps "$plugin"
+          done
+
+          # Resolve transitive dependencies from the libraries we just copied.
+          for _ in 1 2 3; do
+            find "$appdir/lib" -type f -name '*.so*' -print0 | while IFS= read -r -d '' lib; do
+              copy_deps "$lib" || true
+            done
+          done
+
+          {
+            echo '#!/usr/bin/env bash'
+            echo 'set -euo pipefail'
+            echo 'APPDIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"'
+            echo 'export LD_LIBRARY_PATH="$APPDIR/lib:${LD_LIBRARY_PATH:-}"'
+            echo 'export QT_PLUGIN_PATH="$APPDIR/plugins:${QT_PLUGIN_PATH:-}"'
+            echo 'exec "$APPDIR/bin/onpoint" "$@"'
+          } > "$appdir/run-onpoint.sh"
+          chmod +x "$appdir/run-onpoint.sh"
+
+          echo "Checking packaged binary dependencies"
+          LD_LIBRARY_PATH="$appdir/lib" ldd "$appdir/bin/onpoint" | tee /tmp/onpoint-ldd.txt
+          if grep -q 'not found' /tmp/onpoint-ldd.txt; then
+            exit 1
+          fi
+
+          echo "Checking bundled runtime closure"
+          check_unbundled() {
+            local target="$1"
+            LD_LIBRARY_PATH="$appdir/lib" ldd "$target" \
+              | awk '/=> \/.*\.so/ {print $1 " " $3} /^\s*\/.*\.so/ {print $1 " " $1}' \
+              | while read -r soname lib; do
+                  [ -f "$lib" ] || continue
+                  if should_bundle "$lib" && [ "$lib" != "$appdir/lib/$soname" ]; then
+                    echo "Missing bundled runtime library: $soname from $lib"
+                    exit 1
+                  fi
+                done
+          }
+
+          check_unbundled "$appdir/bin/onpoint"
+          find "$appdir/plugins" -type f -name '*.so' -print0 | while IFS= read -r -d '' plugin; do
+            check_unbundled "$plugin"
+          done
+          find "$appdir/lib" -type f -name '*.so*' -print0 | while IFS= read -r -d '' lib; do
+            check_unbundled "$lib" || true
+          done
+
+          tar -C package -czf OnPoint-Linux-x86_64.tar.gz OnPoint-Linux-x86_64
+
+      - name: Upload artifact
+        uses: actions/upload-artifact@v4
+        with:
+          name: OnPoint-Linux-x86_64
+          path: OnPoint-Linux-x86_64.tar.gz
+          if-no-files-found: error
+
   # ─────────────────────────────────────────────────────────────────────────────
   release:
     name: GitHub Release
     if: startsWith(github.ref, 'refs/tags/v') || github.event_name == 'workflow_dispatch'
-    needs: [build-macos, build-windows]
+    needs: [build-macos, build-windows, build-linux]
     runs-on: ubuntu-latest
     env:
       TAG_NAME: ${{ github.event_name == 'workflow_dispatch' && github.event.inputs.tag || github.ref_name }}
@@ -287,3 +476,4 @@ jobs:
           files: |
             OnPoint.dmg
             OnPoint-*-Setup.exe
+            OnPoint-Linux-x86_64.tar.gz
diff --git a/CMakeLists.txt b/CMakeLists.txt
index e55e5b7..36ed545 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -109,11 +109,20 @@ if(WIN32)
         "C:/Program Files (x86)/NDI/NDI Advanced SDK 6"
         "$ENV{NDI_SDK_DIR}"
     )
-else()
+elseif(APPLE)
     set(NDI_SEARCH_PATHS
         "${CMAKE_SOURCE_DIR}/ndi"
         "/Library/NDI SDK for Apple"
         "/usr/local"
+        "$ENV{NDI_SDK_DIR}"
+    )
+else()
+    set(NDI_SEARCH_PATHS
+        "${CMAKE_SOURCE_DIR}/ndi"
+        "/opt/ndi"
+        "/usr/local"
+        "/usr"
+        "$ENV{NDI_SDK_DIR}"
     )
 endif()
 
@@ -131,12 +140,23 @@ foreach(NDI_BASE ${NDI_SEARCH_PATHS})
                     break()
                 endif()
             endforeach()
-        else()
+        elseif(APPLE)
             if(EXISTS "${NDI_BASE}/lib/macOS/libndi.dylib")
                 set(NDI_LIB "${NDI_BASE}/lib/macOS/libndi.dylib")
             elseif(EXISTS "${NDI_BASE}/lib/libndi.dylib")
                 set(NDI_LIB "${NDI_BASE}/lib/libndi.dylib")
             endif()
+        else()
+            foreach(_lib_path
+                "${NDI_BASE}/lib/x86_64-linux-gnu/libndi.so"
+                "${NDI_BASE}/lib/x64/libndi.so"
+                "${NDI_BASE}/lib/libndi.so"
+                "${NDI_BASE}/lib64/libndi.so")
+                if(EXISTS "${_lib_path}")
+                    set(NDI_LIB "${_lib_path}")
+                    break()
+                endif()
+            endforeach()
         endif()
         if(NDI_LIB)
             set(NDI_FOUND TRUE)
@@ -198,11 +218,16 @@ else()
             "Install the NDI 6 SDK for Windows from https://ndi.video/download-ndi-sdk/ "
             "or place the SDK directory under ${CMAKE_SOURCE_DIR}/ndi/.\n"
             "You can also set the NDI_SDK_DIR environment variable to the SDK root.")
-    else()
+    elseif(APPLE)
         message(FATAL_ERROR
             "NDI SDK not found. "
             "Install 'NDI SDK for Apple' (6.x) so CMake can find "
             "Processing.NDI.Lib.h and libndi.dylib.")
+    else()
+        message(FATAL_ERROR
+            "NDI SDK not found. Install the NDI SDK for Linux so CMake can find "
+            "Processing.NDI.Lib.h and libndi.so, place it under ${CMAKE_SOURCE_DIR}/ndi/, "
+            "or set NDI_SDK_DIR to the SDK root.")
     endif()
 endif()
 
@@ -268,6 +293,25 @@ if(APPLE)
 
 endif()
 
+# ── Linux-specific ────────────────────────────────────────────────────────────
+if(UNIX AND NOT APPLE)
+    find_path(DNSSD_INCLUDE_DIR dns_sd.h)
+    find_library(DNSSD_LIB dns_sd)
+    if(NOT DNSSD_INCLUDE_DIR OR NOT DNSSD_LIB)
+        message(FATAL_ERROR
+            "DNS-SD compatibility library not found. Install libavahi-compat-libdnssd-dev "
+            "(Debian/Ubuntu) or the equivalent package for your distribution.")
+    endif()
+
+    target_sources(onpoint PRIVATE src/DnsSdBridge_win.cpp)
+    target_include_directories(onpoint PRIVATE "${DNSSD_INCLUDE_DIR}")
+    target_link_libraries(onpoint PRIVATE "${DNSSD_LIB}")
+    target_compile_definitions(onpoint PRIVATE DNSSD_AVAILABLE=1)
+    message(STATUS "Found DNS-SD compatibility library — session discovery enabled")
+
+    install(TARGETS onpoint RUNTIME DESTINATION bin)
+endif()
+
 # ── Windows-specific ──────────────────────────────────────────────────────────
 if(WIN32)
     # Use the Windows GUI subsystem (no console window)
diff --git a/src/DnsSdBridge_win.cpp b/src/DnsSdBridge_win.cpp
index 53ececb..a9e418e 100644
--- a/src/DnsSdBridge_win.cpp
+++ b/src/DnsSdBridge_win.cpp
@@ -3,7 +3,11 @@
 
 #if defined(DNSSD_AVAILABLE) && DNSSD_AVAILABLE
 
-#include <winsock2.h>
+#ifdef _WIN32
+#  include <winsock2.h>
+#else
+#  include <arpa/inet.h>
+#endif
 #include <dns_sd.h>
 #include <QSocketNotifier>
 #include <vector>
@@ -201,8 +205,8 @@ DnsSdBridge::~DnsSdBridge() {}
 void DnsSdBridge::advertise(const QString&, quint16) {
     QTimer::singleShot(0, this, [this]() {
         emit advertiseError(
-            QStringLiteral("Session discovery unavailable: "
-                           "install Apple Bonjour for Windows"));
+            QStringLiteral("Session discovery unavailable: install a DNS-SD compatibility library "
+                           "(Bonjour on Windows or Avahi libdns_sd on Linux)"));
     });
 }
 void DnsSdBridge::stopAdvertising() {}
diff --git a/src/ui/StreamSourcePanel.cpp b/src/ui/StreamSourcePanel.cpp
index 288127d..0bf14ea 100644
--- a/src/ui/StreamSourcePanel.cpp
+++ b/src/ui/StreamSourcePanel.cpp
@@ -511,7 +511,6 @@ class DecklinkSourceTab : public VideoSourceTab {
     bool         settingSource_  = false;
 #else
     void    refreshSources() override {}
-    QString selectedSource() const override { return {}; }
     void    setCurrentSource(const QString&) override {}
 #endif
 };