diff --git a/list_used_beta_api.lua b/list_used_beta_api.lua
new file mode 100644
index 0000000..0c86474
--- /dev/null
+++ b/list_used_beta_api.lua
@@ -0,0 +1,109 @@
+local eolian = require("eolian")
+local getopt = require("getopt")
+
+local eou = require("utils.eolian_extras")
+
+local exit = false
+local pargs
+
+getopt.parse {
+    usage = "Usage: %prog [OPTIONS] path_to_project [path_to_eo_files]",
+    args = arg,
+    header = [[
+Print all beta C names used in the given project. You can specify a custom
+path to .eo files as the second argument. If you don't, system-wide eo files
+will be used instead.]],
+    descs = {
+        { "h", "help", false, help = "Show this message.",
+            callback = getopt.help_cb(io.stdout)
+        }
+    },
+    error_cb = function(parser, msg)
+        io.stderr:write(msg, "\n")
+        getopt.help(parser, io.stderr)
+        exit = true
+    end,
+    done_cb = function(parser, opts, args)
+        if opts["h"] then
+            exit = true
+        end
+        if #args == 0 then
+            parser:error_cb("project path not specified")
+            return
+        end
+        pargs = args
+    end
+}
+
+if exit then
+    return true
+end
+
+local eos = eolian.new()
+
+if #pargs > 1 then
+    eos:directory_add(pargs[2])
+else
+    eos:system_directory_add()
+end
+
+-- find all source, header and inline files first, we don't have a reasonable
+-- filesystem api available here so this hack is necessary, maybe replace later
+local f = io.popen(("find '%s' -name '*.[chx]'"):format(
+    pargs[1]:gsub("'", "\\'")))
+if not f then
+    error("could not find source files")
+end
+
+local srcs, syms = {}, {}
+
+-- collect source files
+for fn in f:lines() do
+    srcs[#srcs + 1] = fn
+end
+f:close()
+
+-- collect names as a lookup table
+eos:all_eot_files_parse()
+eos:all_eo_files_parse()
+
+local add_syms = function(fun)
+    for i, n in ipairs(fun(eos)) do
+        syms[n] = n
+    end
+end
+
+add_syms(eou.get_c_functions)
+add_syms(eou.get_c_events)
+add_syms(eou.get_c_function_pointers)
+add_syms(eou.get_c_aliases)
+add_syms(eou.get_c_structs)
+add_syms(eou.get_c_enums)
+add_syms(eou.get_c_globals)
+add_syms(eou.get_c_constants)
+
+-- match words in sources against names
+
+local match_names = function(fn)
+    local fs = io.open(fn)
+    if not fs then
+        return
+    end
+    local lnum = 1
+    for l in fs:lines() do
+        -- C names on thel ine
+        for w in l:gmatch("[%a_][%w_]*") do
+            if syms[w] then
+                print(("%s:%d: used beta name '%s'"):format(fn, lnum, w))
+            end
+        end
+        lnum = lnum + 1
+    end
+    fs:close()
+end
+
+for i, fn in ipairs(srcs) do
+    match_names(fn)
+end
+
+return true