diff --git a/libchewing/Dockerfile b/libchewing/Dockerfile
index 389edaadd..b3625028c 100644
--- a/libchewing/Dockerfile
+++ b/libchewing/Dockerfile
@@ -19,4 +19,4 @@ MAINTAINER kcwu@csie.org
 RUN apt-get install -y make autoconf automake libtool texinfo
 
 RUN git clone https://github.com/chewing/libchewing.git
-COPY build.sh chewing_fuzzer.c /src/
+COPY build.sh chewing_fuzzer_common.[ch] chewing_*_fuzzer.c /src/
diff --git a/libchewing/build.sh b/libchewing/build.sh
index b6fab1bc6..a4db16794 100755
--- a/libchewing/build.sh
+++ b/libchewing/build.sh
@@ -25,11 +25,13 @@ make clean all
 # build your fuzzer(s)
 make -C test CFLAGS="$CFLAGS -Dmain=stress_main -Drand=get_fuzz_input" stress.o
 
-$CC $CFLAGS \
-    -o /out/chewing_fuzzer \
-    /src/chewing_fuzzer.c \
-    test/stress.o test/.libs/libtesthelper.a src/.libs/libchewing.a \
-    -lfuzzer $FUZZER_LDFLAGS
+for variant in default random_init dynamic_config; do
+    $CC $CFLAGS \
+	-o /out/chewing_${variant}_fuzzer \
+	/src/chewing_${variant}_fuzzer.c /src/chewing_fuzzer_common.c \
+	test/stress.o test/.libs/libtesthelper.a src/.libs/libchewing.a \
+	-lfuzzer $FUZZER_LDFLAGS
+done
 
 # install data files
 make -C data pkgdatadir=/out install
diff --git a/libchewing/chewing_default_fuzzer.c b/libchewing/chewing_default_fuzzer.c
new file mode 100644
index 000000000..dd6fc7a84
--- /dev/null
+++ b/libchewing/chewing_default_fuzzer.c
@@ -0,0 +1,15 @@
+#include <stdio.h>
+
+#include "chewing_fuzzer_common.h"
+
+int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
+  fuzz_input = fuzz_ptr = data;
+  fuzz_size = size;
+
+  const char* stress_argv[] = {
+      "./chewing_fuzzer", "-loop", "1", NULL,
+  };
+  stress_main(sizeof(stress_argv) / sizeof(stress_argv[0]) - 1,
+              (char**)stress_argv);
+  return 0;
+}
diff --git a/libchewing/chewing_dynamic_config_fuzzer.c b/libchewing/chewing_dynamic_config_fuzzer.c
new file mode 100644
index 000000000..5479c1ee1
--- /dev/null
+++ b/libchewing/chewing_dynamic_config_fuzzer.c
@@ -0,0 +1,15 @@
+#include <stdio.h>
+
+#include "chewing_fuzzer_common.h"
+
+int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
+  fuzz_input = fuzz_ptr = data;
+  fuzz_size = size;
+
+  const char* stress_argv[] = {
+      "./chewing_fuzzer", "-loop", "1", "-extra", NULL,
+  };
+  stress_main(sizeof(stress_argv) / sizeof(stress_argv[0]) - 1,
+              (char**)stress_argv);
+  return 0;
+}
diff --git a/libchewing/chewing_fuzzer.c b/libchewing/chewing_fuzzer.c
deleted file mode 100644
index e7b6e610d..000000000
--- a/libchewing/chewing_fuzzer.c
+++ /dev/null
@@ -1,40 +0,0 @@
-#include <stddef.h>
-#include <stdint.h>
-#include <stdio.h>
-#include <stdlib.h>
-#include <libgen.h>
-
-static const uint8_t* fuzz_ptr;
-static const uint8_t* fuzz_input;
-static size_t fuzz_size;
-
-int stress_main(int argc, char** argv);
-
- int LLVMFuzzerInitialize(int* argc, char*** argv) {
-   char* exe_path = (*argv)[0];
-   char* dir = dirname(exe_path);
-   // Assume data files are at the same location as executable.
-   setenv("CHEWING_PATH", dir, 0);
-   setenv("CHEWING_USER_PATH", "/tmp", 0);
-   return 0;
- }
-
-int get_fuzz_input() {
-  if (fuzz_ptr - fuzz_input >= fuzz_size)
-    return EOF;
-  return *fuzz_ptr++;
-}
-
-int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
-  fuzz_input = fuzz_ptr = data;
-  fuzz_size = size;
-
-  const char *stress_argv[] = {
-    "./chewing_fuzzer",
-    "-extra",
-    "-loop", "1",
-    NULL,
-  };
-  stress_main(4, (char**)stress_argv);
-  return 0;
-}
diff --git a/libchewing/chewing_fuzzer_common.c b/libchewing/chewing_fuzzer_common.c
new file mode 100644
index 000000000..de249df67
--- /dev/null
+++ b/libchewing/chewing_fuzzer_common.c
@@ -0,0 +1,26 @@
+#include "chewing_fuzzer_common.h"
+
+#include <libgen.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+static char userphrase_path[] = "/tmp/chewing_userphrase.db.XXXXXX";
+
+int LLVMFuzzerInitialize(int* argc, char*** argv) {
+  char* exe_path = (*argv)[0];
+  char* dir = dirname(exe_path);
+  // Assume data files are at the same location as executable.
+  setenv("CHEWING_PATH", dir, 0);
+
+  // Specify user db of this process. So we can run multiple fuzzers at the
+  // same time.
+  mktemp(userphrase_path);
+  setenv("TEST_USERPHRASE_PATH", userphrase_path, 0);
+  return 0;
+}
+
+int get_fuzz_input() {
+  if (fuzz_ptr - fuzz_input >= fuzz_size)
+    return EOF;
+  return *fuzz_ptr++;
+}
diff --git a/libchewing/chewing_fuzzer_common.h b/libchewing/chewing_fuzzer_common.h
new file mode 100644
index 000000000..5032d655c
--- /dev/null
+++ b/libchewing/chewing_fuzzer_common.h
@@ -0,0 +1,13 @@
+#ifndef CHEWING_FUZZER_COMMON_H
+#define CHEWING_FUZZER_COMMON_H
+
+#include <stddef.h>
+#include <stdint.h>
+
+const uint8_t* fuzz_ptr;
+const uint8_t* fuzz_input;
+size_t fuzz_size;
+
+int stress_main(int argc, char** argv);
+
+#endif
diff --git a/libchewing/chewing_random_init_fuzzer.c b/libchewing/chewing_random_init_fuzzer.c
new file mode 100644
index 000000000..3e6a841b5
--- /dev/null
+++ b/libchewing/chewing_random_init_fuzzer.c
@@ -0,0 +1,15 @@
+#include <stdio.h>
+
+#include "chewing_fuzzer_common.h"
+
+int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
+  fuzz_input = fuzz_ptr = data;
+  fuzz_size = size;
+
+  const char* stress_argv[] = {
+      "./chewing_fuzzer", "-loop", "1", "-init", "-extra", NULL,
+  };
+  stress_main(sizeof(stress_argv) / sizeof(stress_argv[0]) - 1,
+              (char**)stress_argv);
+  return 0;
+}