diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index e6892e1..df02c1e 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -147,7 +147,7 @@ jobs:
       - run: make ui-deps
       - run: make build
       # The installer from the README one-liner, against a fake GitHub Releases server
-      - run: make scripts-lint install-test changed-areas-test release-check-test
+      - run: make scripts-lint install-test changed-areas-test release-check-test desktop-deps-test
 
   e2e:
     name: Browser tests (Playwright)
diff --git a/Makefile b/Makefile
index ae67bef..2eb6d45 100644
--- a/Makefile
+++ b/Makefile
@@ -199,8 +199,12 @@ LINUX_GTK ?= gtk4
 DESKTOP_TAGS := desktop embedui $(if $(filter gtk3,$(LINUX_GTK)),gtk3)
 DESKTOP_BIN := $(DIST)/wapp-debugger-desktop$(EXE)
 
+.PHONY: desktop-deps
+desktop-deps: ## Check the C compiler and, on Linux, GTK and WebKitGTK; prints how to install what is missing
+	scripts/desktop-deps.sh $(LINUX_GTK)
+
 .PHONY: desktop-build
-desktop-build: ui-build ## Build the desktop app for the current OS (requires CGO)
+desktop-build: desktop-deps ui-build ## Build the desktop app for the current OS (requires CGO)
 	cd server && CGO_ENABLED=1 go build -tags "$(DESKTOP_TAGS)" -trimpath -ldflags "$(LDFLAGS)" -o $(DESKTOP_BIN) ./cmd/wapp-debugger-desktop
 
 .PHONY: icons
@@ -208,7 +212,7 @@ icons: ## Render desktop/icons/icon.svg into the PNG, ICO and ICNS icons (needs
 	node scripts/icons.mjs
 
 .PHONY: desktop-vet
-desktop-vet: ui-build ## go vet the desktop code (with its build tags; the embedded UI must be built)
+desktop-vet: desktop-deps ui-build ## go vet the desktop code (with its build tags; the embedded UI must be built)
 	cd server && CGO_ENABLED=1 go vet -tags "$(DESKTOP_TAGS)" ./cmd/wapp-debugger-desktop
 
 .PHONY: desktop-selftest
@@ -316,6 +320,10 @@ changed-areas-test: ## Test scripts/changed-areas.sh, which CI uses to skip jobs
 release-check-test: ## Test scripts/release-check.sh: no stable release with a pre-release library
 	scripts/release-check_test.sh
 
+.PHONY: desktop-deps-test
+desktop-deps-test: ## Test scripts/desktop-deps.sh against fake pkg-config and compilers
+	scripts/desktop-deps_test.sh
+
 .PHONY: ssh-e2e
 ssh-e2e: ## The viewer against a real OpenSSH server in Docker (throwaway key, no ssh-agent)
 	scripts/ssh-e2e.sh
@@ -323,7 +331,7 @@ ssh-e2e: ## The viewer against a real OpenSSH server in Docker (throwaway key, n
 .PHONY: scripts-lint
 scripts-lint: ## shellcheck the shell scripts (shellcheck binary, or its Docker image)
 	@if command -v shellcheck >/dev/null 2>&1; then shellcheck scripts/*.sh; \
-	else docker run --rm -v "$(ROOT)/scripts:/s:ro" koalaman/shellcheck:v0.10.0 /s/install.sh /s/install_test.sh /s/ssh-e2e.sh /s/desktop-package.sh /s/changed-areas.sh /s/changed-areas_test.sh /s/release-check.sh /s/release-check_test.sh; fi
+	else docker run --rm -v "$(ROOT)/scripts:/s:ro" koalaman/shellcheck:v0.10.0 /s/install.sh /s/install_test.sh /s/ssh-e2e.sh /s/desktop-package.sh /s/changed-areas.sh /s/changed-areas_test.sh /s/release-check.sh /s/release-check_test.sh /s/desktop-deps.sh /s/desktop-deps_test.sh; fi
 
 .PHONY: workflows-lint
 workflows-lint: $(ACTIONLINT) ## Lint GitHub Actions workflows
diff --git a/README.md b/README.md
index 7f19836..88fabb0 100644
--- a/README.md
+++ b/README.md
@@ -158,7 +158,7 @@ What the desktop adds to the browser version (**Settings** in the header):
 - start at login; the window comes back where it was;
 - a notice in the header when a newer version is out (GitHub Releases once a day; can be switched off).
 
-From source: `make desktop-build` (needs GTK4 + WebKitGTK 6.0 on Linux), then `dist/wapp-debugger-desktop [--logs-dir …]`; `--logs-dir` is optional here too. `make desktop-package` builds the installers of the current system; more in [desktop/README.md](desktop/README.md).
+From source: `make desktop-build` (needs a C compiler and, on Linux, GTK4 + WebKitGTK 6.0; `make desktop-deps` checks them and prints how to install what is missing on your system), then `dist/wapp-debugger-desktop [--logs-dir …]`; `--logs-dir` is optional here too. `make desktop-package` builds the installers of the current system; more in [desktop/README.md](desktop/README.md).
 
 ## Docker
 
diff --git a/README.ru.md b/README.ru.md
index 7dbaf68..bdf9f04 100644
--- a/README.ru.md
+++ b/README.ru.md
@@ -157,7 +157,7 @@ wapp-debugger serve --logs-dir /var/www/app/tmp/logs   # откройте http:/
 - запуск при входе в систему; окно открывается там, где было;
 - сообщение в шапке о новой версии (GitHub Releases раз в сутки; отключается).
 
-Из исходников: `make desktop-build` (в Linux нужны GTK4 + WebKitGTK 6.0), затем `dist/wapp-debugger-desktop [--logs-dir …]`; `--logs-dir` и здесь необязателен. `make desktop-package` собирает установщики текущей системы; подробнее — в [desktop/README.md](desktop/README.md).
+Из исходников: `make desktop-build` (нужен компилятор C, а в Linux ещё GTK4 + WebKitGTK 6.0; `make desktop-deps` проверяет их и подсказывает, как поставить недостающее в вашей системе), затем `dist/wapp-debugger-desktop [--logs-dir …]`; `--logs-dir` и здесь необязателен. `make desktop-package` собирает установщики текущей системы; подробнее — в [desktop/README.md](desktop/README.md).
 
 ## Docker
 
diff --git a/desktop/README.md b/desktop/README.md
index 33b7516..e69170c 100644
--- a/desktop/README.md
+++ b/desktop/README.md
@@ -3,7 +3,8 @@
 The desktop viewer is built with Wails v3 on top of `server/internal/*` and the same UI (`ui/`). Its entry point lives in `server/cmd/wapp-debugger-desktop` (build tag `desktop`).
 
 ```sh
-make desktop-build             # build for the current OS (requires CGO)
+make desktop-deps              # check the C compiler, GTK and WebKitGTK; prints how to install what is missing
+make desktop-build             # build for the current OS (requires CGO; runs desktop-deps first)
 make desktop-build LINUX_GTK=gtk3   # Linux with GTK3 + WebKit2GTK 4.1 instead of GTK4
 make desktop-selftest          # open a window and check REST and the event stream inside Wails
 make desktop-dev LOGS_DIR=/path/to/project/tmp/logs
diff --git a/scripts/desktop-deps.sh b/scripts/desktop-deps.sh
new file mode 100755
index 0000000..7631c1b
--- /dev/null
+++ b/scripts/desktop-deps.sh
@@ -0,0 +1,158 @@
+#!/bin/bash
+# Checks what the desktop build needs from the system (a C compiler for cgo; GTK and WebKitGTK on
+# Linux) and, when something is missing, prints how to install it on this system.
+# Usage: desktop-deps.sh [gtk4|gtk3]. Exit 0: all there, 1: something is missing.
+# Tests set DESKTOP_DEPS_OS (uname -s) and DESKTOP_DEPS_OS_RELEASE (/etc/os-release);
+# PKG_CONFIG and CC are the ones cgo uses.
+set -euo pipefail
+
+gtk=${1:-gtk4}
+os=${DESKTOP_DEPS_OS:-$(uname -s)}
+os_release=${DESKTOP_DEPS_OS_RELEASE:-/etc/os-release}
+pkg_config=${PKG_CONFIG:-pkg-config}
+compiler=${CC:-$(go env CC 2>/dev/null || echo cc)}
+compiler=${compiler%% *}
+
+have() { command -v "$1" >/dev/null 2>&1; }
+
+if ! have "$compiler"; then
+  case $os in
+  Darwin)
+    echo "desktop-deps: no C compiler ($compiler) for cgo; install the Xcode command line tools:"
+    echo "  xcode-select --install"
+    exit 1
+    ;;
+  MINGW* | MSYS* | CYGWIN* | Windows_NT)
+    echo "desktop-deps: no C compiler ($compiler) for cgo; install MinGW-w64 GCC, for example from MSYS2"
+    echo "(https://www.msys2.org/), and put its bin directory on PATH:"
+    echo "  pacman -S mingw-w64-ucrt-x86_64-gcc"
+    exit 1
+    ;;
+  esac
+fi
+case $os in Linux) ;; *) exit 0 ;; esac
+
+# The pkg-config modules of Wails v3 (#cgo lines of github.com/wailsapp/wails/v3)
+if [ "$gtk" = gtk3 ]; then
+  modules="gtk+-3.0 webkit2gtk-4.1 gdk-3.0 libsoup-3.0 gio-unix-2.0 glib-2.0 gobject-2.0 x11"
+else
+  modules="gtk4 webkitgtk-6.0 libsoup-3.0 gio-unix-2.0 glib-2.0 gobject-2.0 x11"
+fi
+
+tools=()
+have "$compiler" || tools+=(compiler)
+missing=()
+if have "$pkg_config"; then
+  for module in $modules; do
+    "$pkg_config" --exists "$module" || missing+=("$module")
+  done
+else
+  # Without pkg-config nothing can be checked: the libraries go to the install command as well
+  tools+=(pkg-config)
+  read -ra missing <<<"$modules"
+fi
+[ ${#tools[@]} -eq 0 ] && [ ${#missing[@]} -eq 0 ] && exit 0
+
+id='' id_like='' version_id='' pretty_name=''
+if [ -r "$os_release" ]; then
+  # shellcheck disable=SC1090
+  {
+    read -r id
+    read -r id_like
+    read -r version_id
+    read -r pretty_name
+  } < <(. "$os_release" && printf '%s\n' "${ID:-}" "${ID_LIKE:-}" "${VERSION_ID:-}" "${PRETTY_NAME:-}")
+fi
+family=''
+for candidate in $id $id_like; do
+  case $candidate in
+  debian | ubuntu) family=debian ;;
+  fedora | rhel | centos) family=fedora ;;
+  arch) family=arch ;;
+  opensuse* | suse | sles) family=suse ;;
+  alpine) family=alpine ;;
+  esac
+  [ -n "$family" ] && break
+done
+
+# The package that provides a pkg-config module, a compiler or pkg-config itself
+package() {
+  case $family:$1 in
+  debian:compiler) echo build-essential ;;
+  debian:pkg-config) echo pkg-config ;;
+  debian:gtk4) echo libgtk-4-dev ;;
+  debian:webkitgtk-6.0) echo libwebkitgtk-6.0-dev ;;
+  debian:gtk+-3.0 | debian:gdk-3.0) echo libgtk-3-dev ;;
+  debian:webkit2gtk-4.1) echo libwebkit2gtk-4.1-dev ;;
+  debian:libsoup-3.0) echo libsoup-3.0-dev ;;
+  debian:gio-unix-2.0 | debian:glib-2.0 | debian:gobject-2.0) echo libglib2.0-dev ;;
+  debian:x11) echo libx11-dev ;;
+  arch:compiler) echo base-devel ;;
+  arch:pkg-config) echo pkgconf ;;
+  arch:gtk4) echo gtk4 ;;
+  arch:webkitgtk-6.0) echo webkitgtk-6.0 ;;
+  arch:gtk+-3.0 | arch:gdk-3.0) echo gtk3 ;;
+  arch:webkit2gtk-4.1) echo webkit2gtk-4.1 ;;
+  arch:libsoup-3.0) echo libsoup3 ;;
+  arch:gio-unix-2.0 | arch:glib-2.0 | arch:gobject-2.0) echo glib2 ;;
+  arch:x11) echo libx11 ;;
+  alpine:compiler) echo build-base ;;
+  alpine:pkg-config) echo pkgconf ;;
+  alpine:gtk4) echo gtk4.0-dev ;;
+  alpine:webkitgtk-6.0) echo webkit2gtk-6.0-dev ;;
+  alpine:gtk+-3.0 | alpine:gdk-3.0) echo gtk+3.0-dev ;;
+  alpine:webkit2gtk-4.1) echo webkit2gtk-4.1-dev ;;
+  alpine:libsoup-3.0) echo libsoup3-dev ;;
+  alpine:gio-unix-2.0 | alpine:glib-2.0 | alpine:gobject-2.0) echo glib-dev ;;
+  alpine:x11) echo libx11-dev ;;
+  # dnf and zypper install a package by the pkg-config module it provides
+  fedora:compiler | suse:compiler) echo gcc ;;
+  fedora:pkg-config) echo pkgconf-pkg-config ;;
+  suse:pkg-config) echo pkg-config ;;
+  *) echo "'pkgconfig($1)'" ;;
+  esac
+}
+packages() {
+  local item name list=()
+  for item in "$@"; do
+    name=$(package "$item")
+    [[ " ${list[*]} " == *" $name "* ]] || list+=("$name")
+  done
+  echo "${list[*]}"
+}
+install_command() {
+  case $family in
+  debian) echo "sudo apt-get install -y $(packages "$@")" ;;
+  fedora) echo "sudo dnf install $(packages "$@")" ;;
+  arch) echo "sudo pacman -S --needed $(packages "$@")" ;;
+  suse) echo "sudo zypper install $(packages "$@")" ;;
+  alpine) echo "sudo apk add $(packages "$@")" ;;
+  esac
+}
+
+echo "desktop-deps: the desktop build ($gtk) needs what this system does not have:"
+[ ${#tools[@]} -gt 0 ] && echo "  tools: ${tools[*]/compiler/a C compiler ($compiler)}"
+[ ${#missing[@]} -gt 0 ] && echo "  pkg-config modules: ${missing[*]}"
+echo
+
+old_release=false
+if [ "$gtk" = gtk4 ] && [ -n "$version_id" ]; then
+  case $id in
+  ubuntu) [ "$(printf '%s\n' "$version_id" 24.04 | sort -V | head -1)" != 24.04 ] && old_release=true ;;
+  debian) [ "$(printf '%s\n' "$version_id" 13 | sort -V | head -1)" != 13 ] && old_release=true ;;
+  esac
+fi
+
+if [ "$old_release" = true ]; then
+  echo "${pretty_name:-This release} has no WebKitGTK 6.0 (it comes with Ubuntu 24.04 and Debian 13)."
+  echo "Build with GTK3 and WebKit2GTK 4.1 instead:"
+  echo "  $(install_command "${tools[@]}" gtk+-3.0 webkit2gtk-4.1 libsoup-3.0 glib-2.0 x11)"
+  echo "  make desktop-build LINUX_GTK=gtk3"
+elif [ -n "$family" ]; then
+  echo "Install them (${pretty_name:-$id}):"
+  echo "  $(install_command "${tools[@]}" "${missing[@]}")"
+else
+  echo "Install the development packages that provide these pkg-config modules"
+  echo "(${pretty_name:-an unknown distribution}); their names differ between distributions."
+fi
+exit 1
diff --git a/scripts/desktop-deps_test.sh b/scripts/desktop-deps_test.sh
new file mode 100755
index 0000000..2512633
--- /dev/null
+++ b/scripts/desktop-deps_test.sh
@@ -0,0 +1,92 @@
+#!/bin/bash
+# Tests scripts/desktop-deps.sh against fake pkg-config and compilers: make desktop-deps-test
+set -euo pipefail
+
+ROOT="$(cd "$(dirname "$0")/.." && pwd)"
+WORK="$(mktemp -d)"
+trap 'rm -rf "$WORK"' EXIT
+
+# pkg-config that knows only the modules in $FAKE_PC_MODULES
+cat > "$WORK/pkg-config" <<'EOF'
+#!/bin/bash
+[ "$1" = --exists ] && shift
+for module in "$@"; do
+  [[ " $FAKE_PC_MODULES " == *" $module "* ]] || exit 1
+done
+EOF
+printf '#!/bin/sh\n' > "$WORK/cc"
+chmod +x "$WORK/pkg-config" "$WORK/cc"
+
+GTK4="gtk4 webkitgtk-6.0 libsoup-3.0 gio-unix-2.0 glib-2.0 gobject-2.0 x11"
+GTK3="gtk+-3.0 webkit2gtk-4.1 gdk-3.0 libsoup-3.0 gio-unix-2.0 glib-2.0 gobject-2.0 x11"
+
+failures=0
+indent() { while IFS= read -r line; do echo "    $line"; done <<<"$1"; }
+release() { printf 'ID=%s\nID_LIKE="%s"\nVERSION_ID="%s"\nPRETTY_NAME="%s"\n' "$1" "$2" "$3" "$4" > "$WORK/os-release"; }
+# expect NAME WANT(ok|missing) OS GTK MODULES [TEXT…]: the exit code and every TEXT in the output
+expect() {
+  local name=$1 want=$2 os=$3 gtk=$4 modules=$5 got=0 out text
+  shift 5
+  out=$(DESKTOP_DEPS_OS=$os DESKTOP_DEPS_OS_RELEASE="$WORK/os-release" FAKE_PC_MODULES=$modules \
+    PKG_CONFIG=${FAKE_PKG_CONFIG:-$WORK/pkg-config} CC=${FAKE_CC:-$WORK/cc} \
+    "$ROOT/scripts/desktop-deps.sh" "$gtk" 2>&1) || got=$?
+  if { [ "$want" = ok ] && [ "$got" -ne 0 ]; } || { [ "$want" = missing ] && [ "$got" -eq 0 ]; }; then
+    echo "FAIL $name: want $want, exit $got"
+    indent "$out"
+    failures=$((failures + 1))
+    return
+  fi
+  for text in "$@"; do
+    if ! grep -qF -- "$text" <<<"$out"; then
+      echo "FAIL $name: no \"$text\" in"
+      indent "$out"
+      failures=$((failures + 1))
+    fi
+  done
+}
+
+release ubuntu debian 24.04 "Ubuntu 24.04.5 LTS"
+expect "everything installed" ok Linux gtk4 "$GTK4"
+expect "GTK3 installed" ok Linux gtk3 "$GTK3"
+expect "Ubuntu without GTK4 and WebKitGTK" missing Linux gtk4 "glib-2.0 gobject-2.0 gio-unix-2.0 libsoup-3.0 x11" \
+  "gtk4 webkitgtk-6.0" "Ubuntu 24.04.5 LTS" "sudo apt-get install -y libgtk-4-dev libwebkitgtk-6.0-dev"
+expect "Ubuntu with GTK3" missing Linux gtk3 "glib-2.0 gobject-2.0 gio-unix-2.0 x11" \
+  "sudo apt-get install -y libgtk-3-dev libwebkit2gtk-4.1-dev libsoup-3.0-dev"
+FAKE_PKG_CONFIG="$WORK/no-pkg-config" expect "no pkg-config" missing Linux gtk4 "" \
+  "pkg-config" "sudo apt-get install -y pkg-config"
+FAKE_CC="$WORK/no-cc" expect "no C compiler" missing Linux gtk4 "$GTK4" "build-essential"
+
+release ubuntu debian 22.04 "Ubuntu 22.04.4 LTS"
+expect "Ubuntu 22.04 has no WebKitGTK 6.0" missing Linux gtk4 "" "LINUX_GTK=gtk3"
+
+release debian "" 13 "Debian GNU/Linux 13 (trixie)"
+expect "Debian" missing Linux gtk4 "" "sudo apt-get install -y libgtk-4-dev libwebkitgtk-6.0-dev"
+
+release debian "" "" "Debian GNU/Linux forky/sid"
+expect "Debian testing has no version" missing Linux gtk4 "" "sudo apt-get install -y libgtk-4-dev libwebkitgtk-6.0-dev"
+
+release fedora "" 42 "Fedora Linux 42"
+expect "Fedora" missing Linux gtk4 "" "sudo dnf install 'pkgconfig(gtk4)' 'pkgconfig(webkitgtk-6.0)'"
+
+release linuxmint "ubuntu debian" 22 "Linux Mint 22"
+expect "a derivative of Ubuntu" missing Linux gtk4 "" "sudo apt-get install -y libgtk-4-dev"
+
+release arch "" "" "Arch Linux"
+expect "Arch" missing Linux gtk4 "" "sudo pacman -S --needed gtk4 webkitgtk-6.0"
+
+release opensuse-tumbleweed "opensuse suse" 20260101 "openSUSE Tumbleweed"
+expect "openSUSE" missing Linux gtk4 "" "sudo zypper install 'pkgconfig(gtk4)'"
+
+release alpine "" 3.22 "Alpine Linux v3.22"
+expect "Alpine" missing Linux gtk4 "" "sudo apk add gtk4.0-dev webkit2gtk-6.0-dev"
+
+release gentoo "" 2.17 "Gentoo Linux"
+expect "an unknown distribution" missing Linux gtk4 "" "pkg-config modules" "gtk4 webkitgtk-6.0"
+
+expect "macOS with a compiler" ok Darwin gtk4 ""
+FAKE_CC="$WORK/no-cc" expect "macOS without a compiler" missing Darwin gtk4 "" "xcode-select --install"
+expect "Windows with a compiler" ok MINGW64_NT-10.0-26100 gtk4 ""
+FAKE_CC="$WORK/no-cc" expect "Windows without a compiler" missing MINGW64_NT-10.0-26100 gtk4 "" "MSYS2"
+
+[ "$failures" -eq 0 ] && echo "desktop-deps: ok"
+exit "$failures"