diff --git a/api.md b/api.md
index b859921..3261445 100644
--- a/api.md
+++ b/api.md
@@ -1,8 +1,17 @@
 ## API
 
+### Functions
+
 | Function | Description |
 | -------- | ----------- |
 | `plug#begin(path)` | Start vim-plug block |
 | `plug#end()` | End block, update &rtp, and load plugins when not `vim_starting` |
 | `plug#helptags()` | Regenerate help tags for all plugins |
-| `plug#load(names...)` | Load the plugins immediately |
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+| `plug#load(names...)` | Load the plugins immediately |
+
+### Global variables
+
+| Variable | Type | Description |
+| -------- | ---- | ----------- |
+| `g:plug_home` | String | Directory to store/load plugins. Set by `plug#begin(path)` call. |
+| `g:plugs` | Dict | Information of plugins. Initialized by `plug#begin()` and incrementally set by `Plug` commands |
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