diff --git a/conf/config.yaml b/conf/config.yaml
index affa72db..cad3c17f 100644
--- a/conf/config.yaml
+++ b/conf/config.yaml
@@ -4,3 +4,4 @@ etcd:
 
 plugins:
   - example-plugin
+  - limit-req
diff --git a/conf/nginx.conf b/conf/nginx.conf
index 3dda428e..0eb4a489 100644
--- a/conf/nginx.conf
+++ b/conf/nginx.conf
@@ -21,6 +21,8 @@ http {
     lua_package_path "/usr/share/lua/5.1/?.lua;$prefix/lua/?.lua;;";
     lua_package_cpath '/usr/lib64/lua/5.1/?.so;;';
 
+    lua_shared_dict plugin-limit-req 10m;
+
     lua_ssl_verify_depth 5;
     ssl_session_timeout 86400;
 
diff --git a/lua/apisix.lua b/lua/apisix.lua
index 7b0f03e4..683121e4 100644
--- a/lua/apisix.lua
+++ b/lua/apisix.lua
@@ -7,8 +7,6 @@ local base_plugin = require("apisix.base_plugin")
 local new_tab = require("table.new")
 local load_balancer = require("apisix.balancer") .run
 local ngx = ngx
-local ngx_req = ngx.req
-local ngx_var = ngx.var
 
 
 local _M = {version = 0.1}
@@ -41,17 +39,16 @@ function _M.rewrite_phase()
         ngx_ctx.api_ctx = api_ctx
     end
 
-    api_ctx.method = api_ctx.method or ngx_req.get_method()
-    api_ctx.uri = api_ctx.uri or ngx_var.uri
-    api_ctx.host = api_ctx.host or ngx_var.host
+    local method = core.ctx.get(api_ctx, "method")
+    local uri = core.ctx.get(api_ctx, "uri")
+    local host = core.ctx.get(api_ctx, "host")
 
     local router, dispatch_uri = route_handler.get_router()
     local ok
     if dispatch_uri then
-        ok = router:dispatch(api_ctx.method, api_ctx.uri, api_ctx)
+        ok = router:dispatch(method, uri, api_ctx)
     else
-        ok = router:dispatch(api_ctx.method, api_ctx.host .. api_ctx.uri,
-                             api_ctx)
+        ok = router:dispatch(method, host .. uri, api_ctx)
     end
 
     if not ok then
@@ -66,19 +63,25 @@ function _M.rewrite_phase()
         ngx.say("failed to load plugins: ", err)
     end
 
+    if api_ctx.matched_route.service_id then
+        error("todo: suppport to use service fetch user config")
+    else
+        api_ctx.conf_type = "route"
+        api_ctx.conf_version = api_ctx.matched_route.modifiedIndex
+        api_ctx.conf_id = api_ctx.matched_route.id
+    end
+
     local filter_plugins = base_plugin.filter_plugin(
         api_ctx.matched_route, local_supported_plugins)
 
     api_ctx.filter_plugins = filter_plugins
-    api_ctx.conf_version = api_ctx.matched_route.modifiedIndex
     -- todo: fetch the upstream node status, it may be stored in
     -- different places.
 
     for i = 1, #filter_plugins, 2 do
         local plugin = filter_plugins[i]
         if plugin.rewrite then
-            plugin.rewrite(filter_plugins[i + 1],
-                           api_ctx.conf_version)
+            plugin.rewrite(filter_plugins[i + 1], api_ctx)
         end
     end
 end
@@ -93,8 +96,7 @@ function _M.access_phase()
     for i = 1, #filter_plugins, 2 do
         local plugin = filter_plugins[i]
         if plugin.access then
-            plugin.access(filter_plugins[i + 1],
-                          api_ctx.conf_version)
+            plugin.access(filter_plugins[i + 1], api_ctx)
         end
     end
 end
@@ -109,8 +111,7 @@ function _M.header_filter_phase()
     for i = 1, #filter_plugins, 2 do
         local plugin = filter_plugins[i]
         if plugin.header_filter then
-            plugin.header_filter(filter_plugins[i + 1],
-                                 api_ctx.conf_version)
+            plugin.header_filter(filter_plugins[i + 1], api_ctx)
         end
     end
 end
@@ -125,8 +126,7 @@ function _M.log_phase()
     for i = 1, #filter_plugins, 2 do
         local plugin = filter_plugins[i]
         if plugin.log then
-            plugin.log(filter_plugins[i + 1],
-                       api_ctx.conf_version)
+            plugin.log(filter_plugins[i + 1], api_ctx)
         end
     end
 end
diff --git a/lua/apisix/core.lua b/lua/apisix/core.lua
index 1eff8351..31576f51 100644
--- a/lua/apisix/core.lua
+++ b/lua/apisix/core.lua
@@ -1,8 +1,49 @@
+local tostring = tostring
+local json_encode = require("cjson.safe").encode
+
+
+local function serialise_obj(data)
+    if type(data) == "function" or type(data) == "userdata"
+       or type(data) == "table" then
+        return tostring(data)
+    end
+
+    return data
+end
+
+local function tab_clone_with_serialise(data)
+    if type(data) ~= "table" then
+        return data
+    end
+
+    local t = {}
+    for k, v in pairs(data) do
+        if type(v) == "table" then
+            t[serialise_obj(k)] = tab_clone_with_serialise(v)
+
+        else
+            t[serialise_obj(k)] = serialise_obj(v)
+        end
+    end
+
+    return t
+end
+
+
 return {
     version = 0.1,
     log = require("apisix.core.log"),
     config = require("apisix.core.config"),
-    json = require("cjson.safe"),
+    json = {
+        encode = function(data, force)
+            if force then
+                data = tab_clone_with_serialise(data)
+            end
+
+            return json_encode(data)
+        end,
+        decode = require("cjson.safe").decode,
+    },
     table = {
         new   = require("table.new"),
         clear = require("table.clear"),
@@ -10,4 +51,6 @@ return {
     },
     resp = require("apisix.core.resp"),
     typeof = require("apisix.core.typeof"),
+    global_lru = require("apisix.core.global_lrucache"),
+    ctx = require("apisix.core.ctx"),
 }
diff --git a/lua/apisix/core/ctx.lua b/lua/apisix/core/ctx.lua
new file mode 100644
index 00000000..5750b889
--- /dev/null
+++ b/lua/apisix/core/ctx.lua
@@ -0,0 +1,37 @@
+-- Copyright (C) Yuansheng Wang
+
+local ngx_req = ngx.req
+local ngx_var = ngx.var
+local new_tab = require("table.new")
+
+
+local _M = {version = 0.1}
+
+
+function _M.get(api_ctx, name)
+    local vars = api_ctx.vars
+    if not vars then
+        vars = new_tab(0, 8)
+        api_ctx.vars = vars
+    end
+
+    local val = vars[name]
+    if val then
+        return val
+    end
+
+    if name == "method" then
+        val = ngx_req.get_method()
+    else
+        val = ngx_var[name]
+    end
+
+    if val then
+        vars[name] = val
+    end
+
+    return val
+end
+
+
+return _M
diff --git a/lua/apisix/core/global_lrucache.lua b/lua/apisix/core/global_lrucache.lua
new file mode 100644
index 00000000..f685e9c7
--- /dev/null
+++ b/lua/apisix/core/global_lrucache.lua
@@ -0,0 +1,33 @@
+-- Copyright (C) Yuansheng Wang
+
+local lru_new = require("resty.lrucache").new
+local lru_items = lru_new(200)  -- todo: support to config in yaml.
+
+
+local _M = {version = 0.1}
+
+
+function _M.fetch(name, count, version)
+    local cache = lru_items:get(name)
+    if cache and cache.version == version then
+        return cache
+    end
+
+    cache = lru_new(count)
+    cache.version = version
+    lru_items:set(name, cache)
+    return cache
+end
+
+
+function _M.set(self, name, lru)
+    return lru_items:set(name, lru)
+end
+
+
+function _M.delete(name)
+    return lru_items:delete(name)
+end
+
+
+return _M
diff --git a/lua/apisix/core/log.lua b/lua/apisix/core/log.lua
index dc83cdeb..6e3563db 100644
--- a/lua/apisix/core/log.lua
+++ b/lua/apisix/core/log.lua
@@ -4,6 +4,7 @@ local ngx = ngx
 local ngx_log  = ngx.log
 local ngx_DEBUG= ngx.DEBUG
 local DEBUG    = ngx.config.debug
+-- todo: support stream module
 local cur_level = ngx.config.subsystem == "http" and
                   require "ngx.errlog" .get_sys_filter_level()
 
diff --git a/lua/apisix/plugins/example-plugin.lua b/lua/apisix/plugins/example-plugin.lua
index 5ec7b8c2..586ffab2 100644
--- a/lua/apisix/plugins/example-plugin.lua
+++ b/lua/apisix/plugins/example-plugin.lua
@@ -1,6 +1,5 @@
 local core = require("apisix.core")
 local base_plugin = require("apisix.base_plugin")
-local encode_json = require("cjson.safe").encode
 
 
 -- TODO: need a more powerful way to define the schema
@@ -32,13 +31,15 @@ function _M.check_args(conf)
 end
 
 
-function _M.rewrite(conf)
-    core.log.warn("plugin rewrite phase, conf: ", encode_json(conf))
+function _M.rewrite(conf, api_ctx)
+    core.log.warn("plugin rewrite phase, conf: ", core.json.encode(conf),
+                  " ctx: ", core.json.encode(api_ctx, true))
 end
 
 
-function _M.access(conf)
-    core.log.warn("plugin access phase, conf: ", encode_json(conf))
+function _M.access(conf, api_ctx)
+    core.log.warn("plugin access phase, conf: ", core.json.encode(conf),
+                  " ctx: ", core.json.encode(api_ctx, true))
     -- ngx.say("hit example plugin")
 end
 
diff --git a/lua/apisix/plugins/limit-req.lua b/lua/apisix/plugins/limit-req.lua
new file mode 100644
index 00000000..0bf0919e
--- /dev/null
+++ b/lua/apisix/plugins/limit-req.lua
@@ -0,0 +1,45 @@
+local limit_req = require("resty.limit.req")
+local core = require("apisix.core")
+-- todo: support to config it in yaml
+local cache = core.global_lru.fetch("/plugin/limit-req", 200)
+
+
+local _M = {
+    version = 0.1,
+    priority = 1001,        -- TODO: add a type field, may be a good idea
+    name = "limit-req",
+}
+
+
+function _M.check_args(conf)
+    return true
+end
+
+
+function _M.access(conf, api_ctx)
+    local key = api_ctx.conf_type .. "#" .. api_ctx.conf_id
+    -- core.log.warn("key: ", key, " conf: ", core.json.encode(conf))
+
+    local limit_ins = cache:get(key)
+    if not limit_ins or limit_ins.version ~= api_ctx.conf_version then
+        limit_ins = limit_req.new("plugin-limit-req", conf.rate, conf.burst)
+        cache:set(key, limit_ins)
+    end
+
+    key = core.ctx.get(api_ctx, conf.key)
+
+    local delay, err = limit_ins:incoming(key, true)
+    if not delay then
+        if err == "rejected" then
+            return core.resp(conf.rejected_code)
+        end
+
+        core.log.error("failed to limit req: ", err)
+        return core.resp(500)
+    end
+
+    core.log.info("hit limit-req access")
+end
+
+
+return _M