diff --git a/CMakeLists.txt b/CMakeLists.txt
index 8315e69..9087f6c 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -31,6 +31,9 @@ add_executable(${APP_NAME}
     ${SOURCE_DIR}/backend/x11/event.c
     ${SOURCE_DIR}/backend/x11/window.c
 
+    ${SOURCE_DIR}/bar/cell.c
+    ${SOURCE_DIR}/bar/workspaces.c
+
     ${SOURCE_DIR}/base/color.c
     ${SOURCE_DIR}/base/log.c
     ${SOURCE_DIR}/base/process.c
diff --git a/include/zdwm/bar.h b/include/zdwm/bar.h
new file mode 100644
index 0000000..de973f8
--- /dev/null
+++ b/include/zdwm/bar.h
@@ -0,0 +1,75 @@
+#ifndef ZDWM_BAR_H
+#define ZDWM_BAR_H
+
+#include <stddef.h>
+#include <stdint.h>
+#include <zdwm/action.h>
+#include <zdwm/types.h>
+
+#if defined(__cplusplus)
+extern "C" {
+#endif
+
+typedef struct zdwm_bar_config_t {
+  int32_t height;
+  bool show_top; /* 如果为 false 则 bar 显示在屏幕底部 */
+  uint8_t padding_x;
+  uint16_t fps;
+  const char *font_family;
+  uint32_t font_size;
+  uint32_t dpi;
+
+  const char *bg;
+  const char *fg;
+  const char *layout_bg;
+  const char *layout_fg;
+  const char *binding_mode_bg;
+  const char *binding_mode_fg;
+  const char *window_bg;
+  const char *window_fg;
+  const char *window_focused_bg;
+  const char *window_focused_fg;
+} zdwm_bar_config_t;
+
+typedef struct zdwm_bar_item_t zdwm_bar_item_t;
+
+typedef struct zdwm_bar_cell_api_t {
+  size_t (*get_cell_count)(zdwm_bar_item_t *item);
+  void (*set_cell_count)(zdwm_bar_item_t *item, size_t count);
+
+  void (*cell_set_text)(zdwm_bar_item_t *item, size_t index, const char *text);
+  void (*cell_set_bg)(zdwm_bar_item_t *item, size_t index, const char *color);
+  void (*cell_set_fg)(zdwm_bar_item_t *item, size_t index, const char *color);
+  void (*cell_set_icon)(zdwm_bar_item_t *item, size_t index, zdwm_icon_t icon);
+  void (*cell_set_indicator)(zdwm_bar_item_t *item, size_t index, bool show);
+} zdwm_bar_cell_api_t;
+
+typedef struct zdwm_bar_item_type_t {
+  void *(*create_state)(zdwm_output_id_t output_id, void *config);
+  void (*update)(
+    zdwm_bar_item_t *item,
+    const zdwm_bar_cell_api_t *cells,
+    void *state
+  );
+  zdwm_action_t (*on_click)(
+    zdwm_bar_item_t *item,
+    size_t cell_index,
+    int32_t x,
+    void *state
+  );
+  void (*destroy_state)(void *state);
+  uint32_t update_interval_ms;
+} zdwm_bar_item_type_t;
+
+typedef enum zdwm_bar_side_type_t {
+  ZDWM_BAR_SIDE_LEFT,
+  ZDWM_BAR_SIDE_RIGHT,
+  ZDWM_BAR_SIDE_CENTER_REST, /* 中央剩余部分，用于显示窗口列表 */
+  ZDWM_BAR_SIDE_COUNT,
+} zdwm_bar_side_type_t;
+
+#if defined(__cplusplus)
+}
+#endif
+
+#endif /* ZDWM_BAR_H */
diff --git a/include/zdwm/types.h b/include/zdwm/types.h
index 3a2bbea..c208fbe 100644
--- a/include/zdwm/types.h
+++ b/include/zdwm/types.h
@@ -30,6 +30,19 @@ typedef struct zdwm_output_info_t {
   zdwm_rect_t geometry;
 } zdwm_output_info_t;
 
+typedef enum zdwm_icon_type_t {
+  ZDWM_ICON_TEXT,
+  ZDWM_ICON_IMAGE,
+} zdwm_icon_type_t;
+
+typedef struct zdwm_icon_t {
+  zdwm_icon_type_t type;
+  union {
+    const char *text;
+    const char *image_path;
+  } as;
+} zdwm_icon_t;
+
 #if defined(__cplusplus)
 }
 #endif
diff --git a/src/bar/.clang-format b/src/bar/.clang-format
new file mode 120000
index 0000000..2d11237
--- /dev/null
+++ b/src/bar/.clang-format
@@ -0,0 +1 @@
+../../.clang-format
\ No newline at end of file
diff --git a/src/bar/bar.h b/src/bar/bar.h
new file mode 100644
index 0000000..e3b642e
--- /dev/null
+++ b/src/bar/bar.h
@@ -0,0 +1,22 @@
+#pragma once
+
+#include <stddef.h>
+#include <zdwm/bar.h>
+#include <zdwm/types.h>
+
+#include "bar/types.h"
+
+typedef struct bar_output_t {
+  zdwm_window_id_t window_id;
+  zdwm_output_id_t output_id;
+  bar_side_t sides[ZDWM_BAR_SIDE_COUNT];
+} bar_output_t;
+
+typedef struct bar_t {
+  bar_output_t *bars;
+  size_t count;
+
+  bool visible;
+
+  zdwm_bar_config_t config;
+} bar_t;
diff --git a/src/bar/cell.c b/src/bar/cell.c
new file mode 100644
index 0000000..90819f7
--- /dev/null
+++ b/src/bar/cell.c
@@ -0,0 +1,142 @@
+#include "bar/cell.h"
+
+#include <assert.h>
+#include <stddef.h>
+#include <strings.h>
+#include <zdwm/types.h>
+
+#include "bar/types.h"
+#include "base/array.h"
+#include "base/color.h"
+#include "base/memory.h"
+
+typedef struct color_cache_item_t {
+  const char *text;
+  color_t color;
+} color_cache_item_t;
+
+typedef struct color_cache_t {
+  color_cache_item_t *items;
+  size_t count;
+  size_t capacity;
+} color_cache_t;
+
+static color_cache_t cache = {};
+
+static color_t *find_or_insert_color(const char *text) {
+  assert(text);
+  for (size_t i = 0; i < cache.count; ++i) {
+    auto item = &cache.items[i];
+    if (text == item->text || strcasecmp(text, item->text) == 0) {
+      return &item->color;
+    }
+  }
+
+  auto slot  = array_push(cache.items, cache.count, cache.capacity);
+  slot->text = p_strdup(text);
+  color_parse(text, &slot->color);
+  return &slot->color;
+}
+
+void bar_cell_reset_color_cache(void) {
+  for (size_t i = 0; i < cache.count; ++i) {
+    auto item = &cache.items[i];
+    p_delete(&item->text);
+  }
+  p_clear(cache.items, cache.count);
+  cache.count = 0;
+}
+
+void bar_cell_clean_color_cache(void) {
+  bar_cell_reset_color_cache();
+  p_delete(&cache.items);
+  cache.capacity = 0;
+}
+
+size_t bar_cell_get_count(zdwm_bar_item_t *item) { return item->count; }
+
+void bar_cell_set_count(zdwm_bar_item_t *item, size_t count) {
+  if (item->count == count) return;
+
+  item->count = count;
+  p_realloc(&item->cells, count);
+  p_clear(item->cells, count);
+  item->dirty = true;
+}
+
+void bar_cell_set_text(zdwm_bar_item_t *item, size_t index, const char *text) {
+  if (index >= item->count) return;
+
+  auto cell = &item->cells[index];
+  if (cell->text == text || strcmp(cell->text, text) == 0) return;
+
+  cell->text = text;
+
+  cell->dirty = true;
+  item->dirty = true;
+}
+
+void bar_cell_set_bg(zdwm_bar_item_t *item, size_t index, const char *color) {
+  if (index >= item->count) return;
+
+  auto cell         = &item->cells[index];
+  auto cached_color = find_or_insert_color(color);
+  if (cell->bg == cached_color) return;
+
+  cell->bg = cached_color;
+
+  cell->dirty = true;
+  item->dirty = true;
+}
+
+void bar_cell_set_fg(zdwm_bar_item_t *item, size_t index, const char *color) {
+  if (index >= item->count) return;
+
+  auto cell         = &item->cells[index];
+  auto cached_color = find_or_insert_color(color);
+  if (cell->fg == cached_color) return;
+
+  cell->fg = cached_color;
+
+  cell->dirty = true;
+  item->dirty = true;
+}
+
+void bar_cell_set_icon(zdwm_bar_item_t *item, size_t index, zdwm_icon_t icon) {
+  if (index >= item->count) return;
+
+  auto cell     = &item->cells[index];
+  auto icon_ptr = &cell->icon;
+
+  if (icon_ptr->type == icon.type) {
+    switch (icon.type) {
+    case ZDWM_ICON_TEXT:
+      if (icon_ptr->as.text == icon.as.text ||
+          strcmp(icon_ptr->as.text, icon.as.text) == 0) {
+        return;
+      }
+    case ZDWM_ICON_IMAGE:
+      if (icon_ptr->as.image_path == icon.as.image_path ||
+          strcmp(icon_ptr->as.image_path, icon.as.image_path) == 0) {
+        return;
+      }
+    }
+  }
+
+  *icon_ptr = icon;
+
+  cell->dirty = true;
+  item->dirty = true;
+}
+
+void bar_cell_set_indicator(zdwm_bar_item_t *item, size_t index, bool show) {
+  if (index >= item->count) return;
+
+  auto cell = &item->cells[index];
+  if (cell->show_indicator == show) return;
+
+  cell->show_indicator = show;
+
+  cell->dirty = true;
+  item->dirty = true;
+}
diff --git a/src/bar/cell.h b/src/bar/cell.h
new file mode 100644
index 0000000..d2e781c
--- /dev/null
+++ b/src/bar/cell.h
@@ -0,0 +1,14 @@
+#pragma once
+
+#include <stddef.h>
+#include <zdwm/bar.h>
+#include <zdwm/types.h>
+
+size_t bar_cell_get_count(zdwm_bar_item_t *item);
+void bar_cell_set_count(zdwm_bar_item_t *item, size_t count);
+
+void bar_cell_set_text(zdwm_bar_item_t *item, size_t index, const char *text);
+void bar_cell_set_bg(zdwm_bar_item_t *item, size_t index, const char *color);
+void bar_cell_set_fg(zdwm_bar_item_t *item, size_t index, const char *color);
+void bar_cell_set_icon(zdwm_bar_item_t *item, size_t index, zdwm_icon_t icon);
+void bar_cell_set_indicator(zdwm_bar_item_t *item, size_t index, bool show);
diff --git a/src/bar/types.h b/src/bar/types.h
new file mode 100644
index 0000000..1073b65
--- /dev/null
+++ b/src/bar/types.h
@@ -0,0 +1,50 @@
+#pragma once
+
+#include <stddef.h>
+#include <stdint.h>
+#include <zdwm/bar.h>
+#include <zdwm/types.h>
+
+#include "base/color.h"
+
+typedef struct bar_x_region_t {
+  int32_t start;
+  int32_t end;
+} bar_x_region_t;
+
+typedef struct bar_cell_t {
+  zdwm_icon_t icon;
+  const char *text;
+  const color_t *fg;
+  const color_t *bg;
+  bar_x_region_t region;
+  bool show_indicator;
+  bool dirty;
+} bar_cell_t;
+
+struct zdwm_bar_item_t {
+  bar_cell_t *cells;
+  size_t count;
+  bar_x_region_t region;
+  void *state;
+  uint8_t cell_padding;
+  uint8_t indicator_width;
+  bool dirty;
+};
+
+typedef struct bar_side_t {
+  zdwm_bar_side_type_t type;
+  zdwm_bar_item_t *items;
+  size_t count;
+  size_t capacity;
+  bar_x_region_t region;
+} bar_side_t;
+
+typedef struct bars_t {
+  size_t count;
+  int32_t height;
+  bool show_top; /* 如果为 false 则 bar 显示屏幕底部 */
+  bool visible;
+
+  zdwm_bar_config_t config;
+} bars_t;
diff --git a/src/bar/workspaces.c b/src/bar/workspaces.c
new file mode 100644
index 0000000..17b6dd0
--- /dev/null
+++ b/src/bar/workspaces.c
@@ -0,0 +1,224 @@
+#include "bar/workspaces.h"
+
+#include <assert.h>
+#include <stddef.h>
+#include <stdint.h>
+#include <zdwm/action.h>
+#include <zdwm/bar.h>
+#include <zdwm/listeners.h>
+#include <zdwm/types.h>
+
+#include "base/array.h"
+#include "base/memory.h"
+
+static size_t state_workspace_get_urgent_window_count(
+  const bar_workspace_state_t *state,
+  zdwm_workspace_id_t workspace_id
+) {
+  size_t count = 0;
+
+  for (size_t i = 0; i < state->window_count; ++i) {
+    auto window = &state->windows[i];
+    if (window->workspace == workspace_id && window->urgent) {
+      count++;
+    }
+  }
+
+  return count;
+}
+
+static size_t state_workspace_get_window_count(
+  const bar_workspace_state_t *state,
+  zdwm_workspace_id_t workspace_id
+) {
+  size_t count = 0;
+
+  for (size_t i = 0; i < state->window_count; ++i) {
+    auto window = &state->windows[i];
+    if (window->workspace == workspace_id && !window->skip_taskbar) {
+      count++;
+    }
+  }
+
+  return count;
+}
+
+static zdwm_window_t *state_get_window(
+  const bar_workspace_state_t *state,
+  zdwm_window_id_t window_id
+) {
+  for (size_t i = 0; i < state->window_count; ++i) {
+    auto window = &state->windows[i];
+    if (window->id == window_id) return window;
+  }
+
+  return nullptr;
+}
+
+void *bar_workspaces_create_state(zdwm_output_id_t output_id, void *config) {
+  const bar_workspace_palette_t *palette = config;
+  assert(palette);
+
+  auto state       = p_new(bar_workspace_state_t, 1);
+  state->output_id = output_id;
+  state->palette   = *palette;
+
+  return state;
+}
+
+void bar_workspaces_update(
+  zdwm_bar_item_t *item,
+  const zdwm_bar_cell_api_t *cell_api,
+  void *state
+) {
+  auto data = (bar_workspace_state_t *)state;
+  if (!data->list_inited || !data->active_inited || !data->dirty) return;
+
+  if (data->count != cell_api->get_cell_count(item)) {
+    cell_api->set_cell_count(item, data->count);
+  }
+
+  auto palette = &data->palette;
+  for (size_t i = 0; i < data->count; ++i) {
+    auto workspace = &data->workspaces[i];
+    auto info      = &workspace->info;
+
+    workspace->window_count = state_workspace_get_window_count(state, info->id);
+    workspace->urgent_window_count =
+      state_workspace_get_urgent_window_count(state, info->id);
+
+    bool show_indicator = workspace->window_count;
+    cell_api->cell_set_indicator(item, i, show_indicator);
+
+    cell_api->cell_set_text(item, i, info->name);
+    if (info->id == data->workspace_id) {
+      cell_api->cell_set_bg(item, i, palette->active_bg);
+      cell_api->cell_set_fg(item, i, palette->active_fg);
+      continue;
+    }
+
+    if (workspace->urgent_window_count > 0) {
+      cell_api->cell_set_bg(item, i, palette->urgent_bg);
+      cell_api->cell_set_fg(item, i, palette->urgent_fg);
+      continue;
+    }
+
+    cell_api->cell_set_bg(item, i, palette->bg);
+    cell_api->cell_set_fg(item, i, palette->fg);
+  }
+
+  data->dirty = false;
+}
+
+zdwm_action_t bar_workspace_on_click(
+  zdwm_bar_item_t *item,
+  size_t cell_index,
+  int32_t x,
+  void *state
+) {
+  auto data      = (bar_workspace_state_t *)state;
+  auto workspace = &data->workspaces[cell_index];
+
+  if (workspace->info.id == data->workspace_id) {
+    return (zdwm_action_t){.type = ZDWM_ACTION_NONE};
+  }
+
+  return (zdwm_action_t){
+    .type                          = ZDWM_ACTION_WORKSPACE_SWITCH,
+    .as.switch_workspace.workspace = workspace->info.id,
+  };
+}
+
+void bar_workspace_destroy_state(void *state) {
+  auto data = (bar_workspace_state_t *)state;
+  p_delete(&data->workspaces);
+  p_clear(data, 1);
+}
+
+void bar_workspace_list_filter(
+  const zdwm_workspace_t *list,
+  size_t count,
+  void *user_data
+) {
+  auto state = (bar_workspace_state_t *)user_data;
+
+  for (size_t i = 0; i < count; ++i) {
+    auto workspace = &list[i];
+    if (workspace->output_id != state->output_id) continue;
+
+    auto item = array_push(state->workspaces, state->count, state->capacity);
+    p_clear(item, 1);
+    item->info = *workspace;
+  }
+
+  state->list_inited = true;
+  state->dirty       = true;
+}
+
+void bar_workspace_active_updated(
+  zdwm_output_id_t output_id,
+  zdwm_workspace_id_t workspace_id,
+  void *user_data
+) {
+  auto state = (bar_workspace_state_t *)user_data;
+  if (state->output_id != output_id) return;
+  if (state->workspace_id == workspace_id) return;
+
+  state->workspace_id = workspace_id;
+
+  state->active_inited = true;
+  state->dirty         = true;
+}
+
+void bar_workspace_initial_windows(
+  const zdwm_window_t *list,
+  size_t count,
+  void *user_data
+) {
+  for (size_t i = 0; i < count; ++i) {
+    auto window = &list[i];
+    bar_workspace_window_added(window, user_data);
+  }
+}
+
+void bar_workspace_window_added(const zdwm_window_t *window, void *user_data) {
+  auto state = (bar_workspace_state_t *)user_data;
+
+  auto win =
+    array_push(state->windows, state->window_count, state->window_capacity);
+  *win = *window;
+
+  state->dirty = true;
+}
+
+void bar_workspace_window_updated(
+  const zdwm_window_t *window,
+  void *user_data
+) {
+  auto state = (bar_workspace_state_t *)user_data;
+
+  auto old_window = state_get_window(state, window->id);
+  *old_window     = *window;
+  state->dirty    = true;
+}
+
+void bar_workspace_window_removed(zdwm_window_id_t window_id, void *user_data) {
+  auto state = (bar_workspace_state_t *)user_data;
+
+  bool found   = false;
+  size_t index = 0;
+
+  for (size_t i = 0; i < state->window_count; ++i) {
+    auto window = &state->windows[i];
+    if (window->id == window_id) {
+      found = true;
+      index = i;
+    }
+  }
+
+  if (!found) return;
+
+  if (array_erase(state->windows, state->window_count, index)) {
+    state->dirty = true;
+  }
+}
diff --git a/src/bar/workspaces.h b/src/bar/workspaces.h
new file mode 100644
index 0000000..066dd4b
--- /dev/null
+++ b/src/bar/workspaces.h
@@ -0,0 +1,73 @@
+#pragma once
+
+#include <stddef.h>
+#include <zdwm/action.h>
+#include <zdwm/bar.h>
+#include <zdwm/listeners.h>
+#include <zdwm/types.h>
+
+typedef struct bar_workspace_palette_t {
+  const char *bg;
+  const char *fg;
+  const char *active_bg;
+  const char *active_fg;
+  const char *urgent_bg;
+  const char *urgent_fg;
+} bar_workspace_palette_t;
+
+typedef struct bar_workspace_t {
+  zdwm_workspace_t info;
+  size_t window_count;
+  size_t urgent_window_count;
+} bar_workspace_t;
+
+typedef struct bar_workspace_state_t {
+  zdwm_output_id_t output_id;
+  zdwm_workspace_id_t workspace_id;
+  bar_workspace_t *workspaces;
+  size_t count;
+  size_t capacity;
+
+  zdwm_window_t *windows;
+  size_t window_count;
+  size_t window_capacity;
+
+  bar_workspace_palette_t palette;
+
+  bool list_inited;
+  bool active_inited;
+  bool dirty;
+} bar_workspace_state_t;
+
+void *bar_workspaces_create_state(zdwm_output_id_t output_id, void *config);
+void bar_workspaces_update(
+  zdwm_bar_item_t *item,
+  const zdwm_bar_cell_api_t *cell_api,
+  void *state
+);
+zdwm_action_t bar_workspace_on_click(
+  zdwm_bar_item_t *item,
+  size_t cell_index,
+  int32_t x,
+  void *state
+);
+void bar_workspace_destroy_state(void *state);
+
+void bar_workspace_list_filter(
+  const zdwm_workspace_t *list,
+  size_t count,
+  void *user_data
+);
+void bar_workspace_active_updated(
+  zdwm_output_id_t output_id,
+  zdwm_workspace_id_t workspace_id,
+  void *user_data
+);
+void bar_workspace_initial_windows(
+  const zdwm_window_t *list,
+  size_t count,
+  void *user_data
+);
+void bar_workspace_window_added(const zdwm_window_t *window, void *user_data);
+void bar_workspace_window_updated(const zdwm_window_t *window, void *user_data);
+void bar_workspace_window_removed(zdwm_window_id_t window_id, void *user_data);