diff --git a/WORKSPACE b/WORKSPACE
index 5498f5022..caa501b0e 100644
--- a/WORKSPACE
+++ b/WORKSPACE
@@ -17,7 +17,18 @@ workspace(name = "com_google_fuzztest")
 load("@bazel_tools//tools/build_defs/repo:http.bzl", "http_archive")
 
 ################################################################################
-# Transitive dependencies (not directly required by FuzzTest itself)
+# Direct dependencies required by core FuzzTest (//fuzztest:fuzztest_core)
+################################################################################
+
+http_archive(
+    name = "com_google_absl",
+    sha256 = "0ddd37f347c58d89f449dd189a645bfd97bcd85c5284404a3af27a3ca3476f39",
+    strip_prefix = "abseil-cpp-fad946221cec37175e762c399760f54b9de9a9fa",
+    url = "https://github.com/abseil/abseil-cpp/archive/fad946221cec37175e762c399760f54b9de9a9fa.tar.gz",
+)
+
+################################################################################
+# Transitive dependencies for core FuzzTest
 ################################################################################
 
 # Required by com_google_absl.
@@ -31,16 +42,9 @@ http_archive(
 )
 
 ################################################################################
-# Direct dependencies
+# Direct dependencies required for full FuzzTest (//fuzztest:fuzztest)
 ################################################################################
 
-http_archive(
-    name = "com_google_absl",
-    sha256 = "0ddd37f347c58d89f449dd189a645bfd97bcd85c5284404a3af27a3ca3476f39",
-    strip_prefix = "abseil-cpp-fad946221cec37175e762c399760f54b9de9a9fa",
-    url = "https://github.com/abseil/abseil-cpp/archive/fad946221cec37175e762c399760f54b9de9a9fa.tar.gz",
-)
-
 http_archive(
     name = "com_googlesource_code_re2",
     sha256 = "5bb6875ae1cd1e9fedde98018c346db7260655f86fdb8837e3075103acd3649b",
@@ -63,7 +67,7 @@ http_archive(
 )
 
 ################################################################################
-# Dependencies required for Riegeli
+# Transitive dependencies required by Riegeli (and therefore by full FuzzTest)
 ################################################################################
 
 http_archive(
diff --git a/cmake/AddFuzzTest.cmake b/cmake/AddFuzzTest.cmake
index 8b7b323cc..7f679120b 100644
--- a/cmake/AddFuzzTest.cmake
+++ b/cmake/AddFuzzTest.cmake
@@ -1,5 +1,4 @@
-function(link_fuzztest name)
-  target_link_libraries(${name} PRIVATE fuzztest::fuzztest_gtest_main)
+function(_link_fuzztest_compatibility_mode name)
   if (FUZZTEST_COMPATIBILITY_MODE STREQUAL "libfuzzer")
     EXECUTE_PROCESS (
         COMMAND bash -c "command -v llvm-config || command -v llvm-config-16 || command -v llvm-config-15 || command -v llvm-config-14 || command -v llvm-config-13 || command -v llvm-config-12 || echo"
@@ -12,3 +11,23 @@ function(link_fuzztest name)
     target_link_libraries(${name} PRIVATE ${FUZZER_NO_MAIN})
   endif ()
 endfunction()
+
+function(link_fuzztest name)
+  target_link_libraries(
+    ${name}
+    PRIVATE
+    fuzztest::fuzztest
+    fuzztest::fuzztest_gtest_main
+  )
+  _link_fuzztest_compatibility_mode(${name})
+endfunction()
+
+function(link_fuzztest_core name)
+  target_link_libraries(
+    ${name}
+    PRIVATE
+    fuzztest::fuzztest_core
+    fuzztest::fuzztest_gtest_main
+  )
+  _link_fuzztest_compatibility_mode(${name})
+endfunction()
diff --git a/domain_tests/BUILD b/domain_tests/BUILD
index d23ba2382..aaf19287c 100644
--- a/domain_tests/BUILD
+++ b/domain_tests/BUILD
@@ -28,7 +28,7 @@ cc_test(
         "@com_google_absl//absl/types:optional",
         "@com_google_absl//absl/types:span",
         "@com_google_absl//absl/types:variant",
-        "@com_google_fuzztest//fuzztest:domain",
+        "@com_google_fuzztest//fuzztest:domain_core",
         "@com_google_googletest//:gtest_main",
     ],
 )
@@ -60,7 +60,6 @@ cc_test(
         "@com_google_absl//absl/status",
         "@com_google_absl//absl/time",
         "@com_google_fuzztest//fuzztest:absl_helpers",
-        "@com_google_fuzztest//fuzztest:domain",
         "@com_google_fuzztest//fuzztest:domain_core",
         "@com_google_fuzztest//fuzztest:serialization",
         "@com_google_fuzztest//fuzztest:test_protobuf_cc_proto",
@@ -78,7 +77,7 @@ cc_test(
         "@com_google_absl//absl/container:flat_hash_set",
         "@com_google_absl//absl/random",
         "@com_google_absl//absl/strings",
-        "@com_google_fuzztest//fuzztest:domain",
+        "@com_google_fuzztest//fuzztest:domain_core",
         "@com_google_fuzztest//fuzztest:type_support",
         "@com_google_googletest//:gtest_main",
     ],
@@ -93,7 +92,7 @@ cc_test(
         "@com_google_absl//absl/container:flat_hash_set",
         "@com_google_absl//absl/random",
         "@com_google_fuzztest//fuzztest:coverage",
-        "@com_google_fuzztest//fuzztest:domain",
+        "@com_google_fuzztest//fuzztest:domain_core",
         "@com_google_fuzztest//fuzztest:type_support",
         "@com_google_googletest//:gtest_main",
     ],
@@ -173,7 +172,7 @@ cc_test(
         "@com_google_absl//absl/numeric:int128",
         "@com_google_absl//absl/random",
         "@com_google_absl//absl/types:span",
-        "@com_google_fuzztest//fuzztest:domain",
+        "@com_google_fuzztest//fuzztest:domain_core",
         "@com_google_fuzztest//fuzztest:meta",
         "@com_google_fuzztest//fuzztest:type_support",
         "@com_google_googletest//:gtest_main",
@@ -191,7 +190,7 @@ cc_test(
         "@com_google_absl//absl/status",
         "@com_google_absl//absl/strings",
         "@com_google_absl//absl/types:span",
-        "@com_google_fuzztest//fuzztest:domain",
+        "@com_google_fuzztest//fuzztest:domain_core",
         "@com_google_fuzztest//fuzztest:serialization",
         "@com_google_googletest//:gtest_main",
     ],
@@ -203,7 +202,7 @@ cc_test(
     deps = [
         ":domain_testing",
         "@com_google_absl//absl/random",
-        "@com_google_fuzztest//fuzztest:domain",
+        "@com_google_fuzztest//fuzztest:domain_core",
         "@com_google_googletest//:gtest_main",
     ],
 )
@@ -214,7 +213,7 @@ cc_test(
     deps = [
         ":domain_testing",
         "@com_google_absl//absl/random",
-        "@com_google_fuzztest//fuzztest:domain",
+        "@com_google_fuzztest//fuzztest:domain_core",
         "@com_google_googletest//:gtest_main",
     ],
 )
@@ -228,7 +227,7 @@ cc_test(
         "@com_google_absl//absl/random",
         "@com_google_absl//absl/time",
         "@com_google_absl//absl/types:span",
-        "@com_google_fuzztest//fuzztest:domain",
+        "@com_google_fuzztest//fuzztest:domain_core",
         "@com_google_googletest//:gtest_main",
     ],
 )
@@ -240,7 +239,7 @@ cc_test(
         ":domain_testing",
         "@com_google_absl//absl/container:flat_hash_set",
         "@com_google_absl//absl/random",
-        "@com_google_fuzztest//fuzztest:domain",
+        "@com_google_fuzztest//fuzztest:domain_core",
         "@com_google_googletest//:gtest_main",
     ],
 )
diff --git a/domain_tests/CMakeLists.txt b/domain_tests/CMakeLists.txt
index 1d61eb064..efa6cc9db 100644
--- a/domain_tests/CMakeLists.txt
+++ b/domain_tests/CMakeLists.txt
@@ -15,7 +15,7 @@ fuzztest_cc_test(
     absl::optional
     absl::span
     absl::variant
-    fuzztest::domain
+    fuzztest::domain_core
     GTest::gmock_main
 )
 
@@ -48,7 +48,6 @@ fuzztest_cc_test(
     absl::status
     absl::time
     fuzztest::absl_helpers
-    fuzztest::domain
     fuzztest::domain_core
     fuzztest::serialization
     test_protobuf
@@ -67,7 +66,7 @@ fuzztest_cc_test(
     absl::flat_hash_set
     absl::random_random
     absl::strings
-    fuzztest::domain
+    fuzztest::domain_core
     fuzztest::type_support
     GTest::gmock_main
 )
@@ -83,7 +82,7 @@ fuzztest_cc_test(
     absl::flat_hash_set
     absl::random_random
     fuzztest::coverage
-    fuzztest::domain
+    fuzztest::domain_core
     fuzztest::type_support
     GTest::gmock_main
 )
@@ -166,7 +165,7 @@ fuzztest_cc_test(
     absl::int128
     absl::random_random
     absl::span
-    fuzztest::domain
+    fuzztest::domain_core
     fuzztest::meta
     fuzztest::type_support
     GTest::gmock_main
@@ -185,7 +184,7 @@ fuzztest_cc_test(
     absl::status
     absl::strings
     absl::span
-    fuzztest::domain
+    fuzztest::domain_core
     fuzztest::serialization
     GTest::gmock_main
 )
@@ -198,7 +197,7 @@ fuzztest_cc_test(
   DEPS
     fuzztest::domain_testing
     absl::random_random
-    fuzztest::domain
+    fuzztest::domain_core
     GTest::gmock_main
 )
 
@@ -210,7 +209,7 @@ fuzztest_cc_test(
   DEPS
     fuzztest::domain_testing
     absl::random_random
-    fuzztest::domain
+    fuzztest::domain_core
     GTest::gmock_main
 )
 
@@ -225,7 +224,7 @@ fuzztest_cc_test(
     absl::random_random
     absl::time
     absl::span
-    fuzztest::domain
+    fuzztest::domain_core
     GTest::gmock_main
 )
 
@@ -238,6 +237,6 @@ fuzztest_cc_test(
     fuzztest::domain_testing
     absl::flat_hash_set
     absl::random_random
-    fuzztest::domain
+    fuzztest::domain_core
     GTest::gmock_main
 )
diff --git a/domain_tests/aggregate_combinators_test.cc b/domain_tests/aggregate_combinators_test.cc
index f6cca1a16..a99d55816 100644
--- a/domain_tests/aggregate_combinators_test.cc
+++ b/domain_tests/aggregate_combinators_test.cc
@@ -28,7 +28,7 @@
 #include "absl/types/optional.h"
 #include "absl/types/span.h"
 #include "absl/types/variant.h"
-#include "./fuzztest/domain.h"
+#include "./fuzztest/domain_core.h"
 #include "./domain_tests/domain_testing.h"
 
 namespace fuzztest {
diff --git a/domain_tests/arbitrary_domains_test.cc b/domain_tests/arbitrary_domains_test.cc
index db6370e9e..821b87cd6 100644
--- a/domain_tests/arbitrary_domains_test.cc
+++ b/domain_tests/arbitrary_domains_test.cc
@@ -35,7 +35,7 @@
 #include "absl/random/random.h"
 #include "absl/status/status.h"
 #include "absl/time/time.h"
-#include "./fuzztest/domain.h"  // IWYU pragma: keep
+#include "./fuzztest/domain_core.h"  // IWYU pragma: keep
 #include "./domain_tests/domain_testing.h"
 #include "./fuzztest/internal/domains/absl_helpers.h"
 #include "./fuzztest/internal/domains/arbitrary_impl.h"
diff --git a/domain_tests/container_combinators_test.cc b/domain_tests/container_combinators_test.cc
index 193bab5dd..92268872e 100644
--- a/domain_tests/container_combinators_test.cc
+++ b/domain_tests/container_combinators_test.cc
@@ -33,7 +33,7 @@
 #include "absl/container/flat_hash_set.h"
 #include "absl/random/random.h"
 #include "absl/strings/str_cat.h"
-#include "./fuzztest/domain.h"
+#include "./fuzztest/domain_core.h"
 #include "./domain_tests/domain_testing.h"
 #include "./fuzztest/internal/type_support.h"
 
diff --git a/domain_tests/container_test.cc b/domain_tests/container_test.cc
index a2c5d4517..6336ba8a7 100644
--- a/domain_tests/container_test.cc
+++ b/domain_tests/container_test.cc
@@ -32,7 +32,7 @@
 #include "absl/container/flat_hash_map.h"
 #include "absl/container/flat_hash_set.h"
 #include "absl/random/random.h"
-#include "./fuzztest/domain.h"
+#include "./fuzztest/domain_core.h"
 #include "./domain_tests/domain_testing.h"
 #include "./fuzztest/internal/coverage.h"
 #include "./fuzztest/internal/type_support.h"
diff --git a/domain_tests/misc_domains_test.cc b/domain_tests/misc_domains_test.cc
index 0bfaac75d..531d1fc9d 100644
--- a/domain_tests/misc_domains_test.cc
+++ b/domain_tests/misc_domains_test.cc
@@ -27,7 +27,7 @@
 #include "absl/numeric/int128.h"
 #include "absl/random/random.h"
 #include "absl/types/span.h"
-#include "./fuzztest/domain.h"
+#include "./fuzztest/domain_core.h"
 #include "./domain_tests/domain_testing.h"
 #include "./fuzztest/internal/meta.h"
 #include "./fuzztest/internal/type_support.h"
diff --git a/domain_tests/numeric_domains_test.cc b/domain_tests/numeric_domains_test.cc
index 7853f55e6..57d6d5050 100644
--- a/domain_tests/numeric_domains_test.cc
+++ b/domain_tests/numeric_domains_test.cc
@@ -33,7 +33,7 @@
 #include "absl/strings/str_cat.h"
 #include "absl/strings/substitute.h"
 #include "absl/types/span.h"
-#include "./fuzztest/domain.h"
+#include "./fuzztest/domain_core.h"
 #include "./domain_tests/domain_testing.h"
 #include "./fuzztest/internal/serialization.h"
 
diff --git a/domain_tests/pointer_domains_test.cc b/domain_tests/pointer_domains_test.cc
index 717328628..9330bcd7b 100644
--- a/domain_tests/pointer_domains_test.cc
+++ b/domain_tests/pointer_domains_test.cc
@@ -21,7 +21,7 @@
 #include "gmock/gmock.h"
 #include "gtest/gtest.h"
 #include "absl/random/random.h"
-#include "./fuzztest/domain.h"
+#include "./fuzztest/domain_core.h"
 #include "./domain_tests/domain_testing.h"
 
 namespace fuzztest {
diff --git a/domain_tests/recursive_domains_test.cc b/domain_tests/recursive_domains_test.cc
index 8294a2297..e9072884c 100644
--- a/domain_tests/recursive_domains_test.cc
+++ b/domain_tests/recursive_domains_test.cc
@@ -30,7 +30,7 @@
 #include "gmock/gmock.h"
 #include "gtest/gtest.h"
 #include "absl/random/random.h"
-#include "./fuzztest/domain.h"
+#include "./fuzztest/domain_core.h"
 #include "./domain_tests/domain_testing.h"
 
 namespace fuzztest {
diff --git a/domain_tests/specific_value_domains_test.cc b/domain_tests/specific_value_domains_test.cc
index 2f4e789bf..215a6f987 100644
--- a/domain_tests/specific_value_domains_test.cc
+++ b/domain_tests/specific_value_domains_test.cc
@@ -24,7 +24,7 @@
 #include "absl/random/random.h"
 #include "absl/time/time.h"
 #include "absl/types/span.h"
-#include "./fuzztest/domain.h"
+#include "./fuzztest/domain_core.h"
 #include "./domain_tests/domain_testing.h"
 
 namespace fuzztest {
diff --git a/domain_tests/string_domains_test.cc b/domain_tests/string_domains_test.cc
index 083e3ef1f..057b03719 100644
--- a/domain_tests/string_domains_test.cc
+++ b/domain_tests/string_domains_test.cc
@@ -25,7 +25,7 @@
 #include "gtest/gtest.h"
 #include "absl/container/flat_hash_set.h"
 #include "absl/random/random.h"
-#include "./fuzztest/domain.h"
+#include "./fuzztest/domain_core.h"
 #include "./domain_tests/domain_testing.h"
 
 namespace fuzztest {
diff --git a/e2e_tests/testdata/BUILD b/e2e_tests/testdata/BUILD
index b59efa2f6..e27baffda 100644
--- a/e2e_tests/testdata/BUILD
+++ b/e2e_tests/testdata/BUILD
@@ -75,7 +75,7 @@ cc_binary(
     testonly = 1,
     srcs = ["fuzz_tests_with_invalid_seeds.cc"],
     deps = [
-        "@com_google_fuzztest//fuzztest",
+        "@com_google_fuzztest//fuzztest:fuzztest_core",
         "@com_google_fuzztest//fuzztest:fuzztest_gtest_main",
     ],
 )
@@ -85,7 +85,7 @@ cc_binary(
     testonly = 1,
     srcs = ["dynamically_registered_fuzz_tests.cc"],
     deps = [
-        "@com_google_fuzztest//fuzztest",
+        "@com_google_fuzztest//fuzztest:fuzztest_core",
         "@com_google_fuzztest//fuzztest:fuzztest_gtest_main",
     ],
 )
diff --git a/e2e_tests/testdata/dynamically_registered_fuzz_tests.cc b/e2e_tests/testdata/dynamically_registered_fuzz_tests.cc
index 8d4591d9f..e86aec681 100644
--- a/e2e_tests/testdata/dynamically_registered_fuzz_tests.cc
+++ b/e2e_tests/testdata/dynamically_registered_fuzz_tests.cc
@@ -12,7 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-#include "./fuzztest/fuzztest.h"
+#include "./fuzztest/fuzztest_core.h"
 
 namespace {
 
diff --git a/e2e_tests/testdata/fuzz_tests_with_invalid_seeds.cc b/e2e_tests/testdata/fuzz_tests_with_invalid_seeds.cc
index 2596ea150..37b836e98 100644
--- a/e2e_tests/testdata/fuzz_tests_with_invalid_seeds.cc
+++ b/e2e_tests/testdata/fuzz_tests_with_invalid_seeds.cc
@@ -14,7 +14,7 @@
 
 // Fuzz test examples to be used by `functional_test` only.
 
-#include "./fuzztest/fuzztest.h"
+#include "./fuzztest/fuzztest_core.h"
 
 namespace {
 
diff --git a/fuzztest/BUILD b/fuzztest/BUILD
index e11ea2c4e..7f4bab2fb 100644
--- a/fuzztest/BUILD
+++ b/fuzztest/BUILD
@@ -39,10 +39,28 @@ config_setting(
 
 cc_library(
     name = "fuzztest",
-    srcs = ["fuzztest.cc"],
     hdrs = ["fuzztest.h"],
     deps = [
         ":domain",
+        ":fuzztest_macros",
+    ],
+)
+
+cc_library(
+    name = "fuzztest_core",
+    hdrs = ["fuzztest_core.h"],
+    deps = [
+        ":domain_core",
+        ":fuzztest_macros",
+    ],
+)
+
+cc_library(
+    name = "fuzztest_macros",
+    hdrs = [
+        "fuzztest_macros.h",
+    ],
+    deps = [
         ":io",
         ":registration",
         ":registry",
@@ -319,7 +337,6 @@ cc_library(
     hdrs = ["internal/fixture_driver.h"],
     deps = [
         ":any",
-        ":domain",
         ":domain_core",
         ":logging",
         ":registration",
@@ -392,7 +409,7 @@ cc_test(
     name = "io_test",
     srcs = ["internal/io_test.cc"],
     deps = [
-        ":fuzztest",
+        ":fuzztest_core",
         ":io",
         "@com_google_absl//absl/strings",
         "@com_google_googletest//:gtest_main",
@@ -432,7 +449,6 @@ cc_library(
     name = "registration",
     hdrs = ["internal/registration.h"],
     deps = [
-        ":domain",
         ":domain_core",
         ":meta",
         ":type_support",
@@ -467,7 +483,6 @@ cc_library(
     deps = [
         ":configuration",
         ":coverage",
-        ":domain",
         ":domain_core",
         ":fixture_driver",
         ":flag_name",
@@ -495,7 +510,7 @@ cc_test(
     name = "runtime_test",
     srcs = ["internal/runtime_test.cc"],
     deps = [
-        ":domain",
+        ":domain_core",
         ":runtime",
         ":test_protobuf_cc_proto",
         "@com_google_absl//absl/time",
@@ -599,7 +614,6 @@ cc_test(
     name = "table_of_recent_compares_test",
     srcs = ["internal/table_of_recent_compares_test.cc"],
     deps = [
-        ":domain",
         ":table_of_recent_compares",
         "@com_google_absl//absl/random",
         "@com_google_googletest//:gtest_main",
diff --git a/fuzztest/CMakeLists.txt b/fuzztest/CMakeLists.txt
index 7438df7e8..a2016be61 100644
--- a/fuzztest/CMakeLists.txt
+++ b/fuzztest/CMakeLists.txt
@@ -11,10 +11,27 @@ fuzztest_cc_library(
     fuzztest
   HDRS
     "fuzztest.h"
-  SRCS
-    "fuzztest.cc"
   DEPS
     fuzztest::domain
+    fuzztest::fuzztest_macros
+)
+
+fuzztest_cc_library(
+  NAME
+    fuzztest_core
+  HDRS
+    "fuzztest_core.h"
+  DEPS
+    fuzztest::domain_core
+    fuzztest::fuzztest_macros
+)
+
+fuzztest_cc_library(
+  NAME
+    fuzztest_macros
+  HDRS
+    "fuzztest_macros.h"
+  DEPS
     fuzztest::io
     fuzztest::registration
     fuzztest::registry
@@ -253,7 +270,6 @@ fuzztest_cc_library(
     "internal/fixture_driver.cc"
   DEPS
     fuzztest::any
-    fuzztest::domain
     fuzztest::domain_core
     fuzztest::logging
     fuzztest::registration
@@ -324,7 +340,7 @@ fuzztest_cc_test(
   SRCS
     "internal/io_test.cc"
   DEPS
-    fuzztest::fuzztest
+    fuzztest::fuzztest_core
     fuzztest::io
     absl::strings
     GTest::gmock_main
@@ -371,7 +387,6 @@ fuzztest_cc_library(
   HDRS
     "internal/registration.h"
   DEPS
-    fuzztest::domain
     fuzztest::domain_core
     fuzztest::meta
     fuzztest::type_support
@@ -407,7 +422,6 @@ fuzztest_cc_library(
   DEPS
     fuzztest::configuration
     fuzztest::coverage
-    fuzztest::domain
     fuzztest::domain_core
     fuzztest::fixture_driver
     fuzztest::io
@@ -435,7 +449,7 @@ fuzztest_cc_test(
   SRCS
     "internal/runtime_test.cc"
   DEPS
-    fuzztest::domain
+    fuzztest::domain_core
     fuzztest::runtime
     test_protobuf
     absl::time
@@ -552,7 +566,6 @@ fuzztest_cc_test(
   SRCS
     "internal/table_of_recent_compares_test.cc"
   DEPS
-    fuzztest::domain
     fuzztest::table_of_recent_compares
     absl::random_random
     GTest::gmock_main
diff --git a/fuzztest/fuzztest.cc b/fuzztest/fuzztest.cc
deleted file mode 100644
index b68ead141..000000000
--- a/fuzztest/fuzztest.cc
+++ /dev/null
@@ -1,41 +0,0 @@
-// Copyright 2022 Google LLC
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//      http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-#include "./fuzztest/fuzztest.h"
-
-#include <string>
-#include <string_view>
-#include <tuple>
-#include <vector>
-
-#include "./fuzztest/internal/io.h"
-
-namespace fuzztest {
-
-std::vector<std::tuple<std::string>> ReadFilesFromDirectory(
-    std::string_view dir) {
-  std::vector<internal::FilePathAndData> files =
-      internal::ReadFileOrDirectory({dir.data(), dir.size()});
-
-  std::vector<std::tuple<std::string>> out;
-  out.reserve(files.size());
-
-  for (const internal::FilePathAndData& file : files) {
-    out.push_back(std::make_tuple(file.data));
-  }
-
-  return out;
-}
-
-}  // namespace fuzztest
diff --git a/fuzztest/fuzztest.h b/fuzztest/fuzztest.h
index 3faae1405..a153e36e1 100644
--- a/fuzztest/fuzztest.h
+++ b/fuzztest/fuzztest.h
@@ -15,115 +15,9 @@
 #ifndef FUZZTEST_FUZZTEST_FUZZTEST_H_
 #define FUZZTEST_FUZZTEST_FUZZTEST_H_
 
-#include <string>
-#include <string_view>
-#include <tuple>
-#include <vector>
-
 // IWYU pragma: begin_exports
 #include "./fuzztest/domain.h"
-#include "./fuzztest/internal/registration.h"
-#include "./fuzztest/internal/registry.h"
+#include "./fuzztest/fuzztest_macros.h"
 // IWYU pragma: end_exports
 
-namespace fuzztest {
-
-// The FUZZ_TEST macro registers a fuzz test.
-//
-// Fuzz tests are parameterized unit tests, also called property-based tests.
-// The tested property is captured by a function with some parameters, and the
-// input domains of the parameters can be specified with the FUZZ_TEST macro
-// that registers and instantiates the test:
-//
-//   void CallingMyApiNeverCrashes(int x, const std::string& s) {
-//     bool result = MyApi(x, s);  // This function call should never crash.
-//     ASSERT_TRUE(result);        // Can have explicit assertions too.
-//   }
-//   FUZZ_TEST(MySuite, CallingMyApiNeverCrashes)
-//     .WithDomains(/*x:*/fuzztest::InRange(0,10),
-//                  /*s:*/fuzztest::AsciiString())
-//     .WithSeeds({{5, "Foo"}, {10, "Bar"}});
-//
-// where `MySuite` is an identifier for a group of related tests, and
-// `CallingMyApiNeverCrashes` is the name of the test and also the name of the
-// "property function". The property function can have any number of parameters.
-// The input domain of each parameter can be assigned using `.WithDomains()`,
-// and the initial seed values can be provided using `.WithSeeds()`.
-//
-// When each parameter's input domain is `Arbitrary<T>()`, which allows any
-// value of a given type T, i.e.:
-//
-//   FUZZ_TEST(MySuite, CallingMyApiNeverCrashes)
-//     .WithDomains(/*x:*/fuzztest::Arbitrary<int>(),
-//                  /*s:*/fuzztest::Arbitrary<std::string>());
-//
-// then the input domain assignment with `.WithDomains()` can be omitted:
-//
-//   FUZZ_TEST(MySuite, CallingMyApiNeverCrashes);
-//
-// Note: When specifying both the domains and seeds, the domain clause has to
-// be specified first.
-#define FUZZ_TEST(suite_name, func) INTERNAL_FUZZ_TEST(suite_name, func)
-
-// The FUZZ_TEST_F macro registers a fuzz test that uses a test fixture.
-//
-// The first parameter is the name of the fixture class, which is also used as
-// the name of the test suite. The second parameter is the name of the property
-// function (also used as the test name), which must be defined as a public
-// member of the fixture class.
-//
-// A test fixture can be any default-constructible class. The fixture's setup
-// code should be in its constructor, and the teardown code should be in its
-// destructor. While running the fuzz test, which involves calling the property
-// function multiple times with various inputs, the fixture will be instantiated
-// only once at the beginning and destroyed at the end of the fuzz test. In
-// particular, the same instance will be used in all calls to the property
-// function.
-//
-// If the fixture you are using is a GoogleTest fixture (i.e., it extends
-// `::testing::Test`, either directly or indirectly), then you will additionally
-// need to wrap the fixture in an adapter. For more details, see
-// https://github.com/google/fuzztest/blob/main/doc/fixtures.md.
-//
-// Just like the FUZZ_TEST macro, the FUZZ_TEST_F macro allows specifying the
-// domains and seeds using the `.WithDomains()` and `.WithSeeds()` clauses.
-//
-// Example:
-//
-//   class FooFuzzTest {
-//    public:
-//     FooFuzzTest() { foo_.SetUp(); }
-//     ~FooFuzzTest() { foo_.TearDown(); }
-//
-//     void CallingFooBarNeverCrashes(int x, const std::string& s) {
-//       bool result = foo_.Bar(x, s);
-//       ASSERT_TRUE(result);
-//     }
-//
-//    private:
-//     Foo foo_;
-//   };
-//   FUZZ_TEST_F(FooFuzzTest, CallingFooBarNeverCrashes)
-//     .WithDomains(/*x:*/fuzztest::Positive<int>(),
-//                  /*s:*/fuzztest::AsciiString())
-//     .WithSeeds({{5, "Foo"}, {10, "Bar"}});
-//
-#define FUZZ_TEST_F(fixture, func) \
-  INTERNAL_FUZZ_TEST_F(fixture, func, fixture, func)
-
-// Reads files as strings from the directory `dir` and returns a vector usable
-// by .WithSeeds().
-//
-// Example:
-//
-//   void MyThingNeverCrashes(const std::string& s) {
-//     DoThingsWith(s);
-//   }
-//   FUZZ_TEST(MySuite, MyThingNeverCrashes)
-//     .WithSeeds(ReadFilesFromDirectory(kCorpusPath));
-std::vector<std::tuple<std::string>> ReadFilesFromDirectory(
-    std::string_view dir);
-
-}  // namespace fuzztest
-
 #endif  // FUZZTEST_FUZZTEST_FUZZTEST_H_
diff --git a/fuzztest/fuzztest_core.h b/fuzztest/fuzztest_core.h
new file mode 100644
index 000000000..23cd116f1
--- /dev/null
+++ b/fuzztest/fuzztest_core.h
@@ -0,0 +1,23 @@
+// Copyright 2023 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#ifndef FUZZTEST_FUZZTEST_FUZZTEST_CORE_H_
+#define FUZZTEST_FUZZTEST_FUZZTEST_CORE_H_
+
+// IWYU pragma: begin_exports
+#include "./fuzztest/domain_core.h"
+#include "./fuzztest/fuzztest_macros.h"
+// IWYU pragma: end_exports
+
+#endif  // FUZZTEST_FUZZTEST_FUZZTEST_CORE_H_
diff --git a/fuzztest/fuzztest_macros.h b/fuzztest/fuzztest_macros.h
new file mode 100644
index 000000000..6228e2fbc
--- /dev/null
+++ b/fuzztest/fuzztest_macros.h
@@ -0,0 +1,131 @@
+// Copyright 2022 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#ifndef FUZZTEST_FUZZTEST_FUZZTEST_MACROS_H_
+#define FUZZTEST_FUZZTEST_FUZZTEST_MACROS_H_
+
+#include <string>
+#include <string_view>
+#include <tuple>
+#include <vector>
+
+// IWYU pragma: begin_exports
+#include "./fuzztest/internal/io.h"
+#include "./fuzztest/internal/registration.h"
+#include "./fuzztest/internal/registry.h"
+// IWYU pragma: end_exports
+
+namespace fuzztest {
+
+// The FUZZ_TEST macro registers a fuzz test.
+//
+// Fuzz tests are parameterized unit tests, also called property-based tests.
+// The tested property is captured by a function with some parameters, and the
+// input domains of the parameters can be specified with the FUZZ_TEST macro
+// that registers and instantiates the test:
+//
+//   void CallingMyApiNeverCrashes(int x, const std::string& s) {
+//     bool result = MyApi(x, s);  // This function call should never crash.
+//     ASSERT_TRUE(result);        // Can have explicit assertions too.
+//   }
+//   FUZZ_TEST(MySuite, CallingMyApiNeverCrashes)
+//     .WithDomains(/*x:*/fuzztest::InRange(0,10),
+//                  /*s:*/fuzztest::AsciiString())
+//     .WithSeeds({{5, "Foo"}, {10, "Bar"}});
+//
+// where `MySuite` is an identifier for a group of related tests, and
+// `CallingMyApiNeverCrashes` is the name of the test and also the name of the
+// "property function". The property function can have any number of parameters.
+// The input domain of each parameter can be assigned using `.WithDomains()`,
+// and the initial seed values can be provided using `.WithSeeds()`.
+//
+// When each parameter's input domain is `Arbitrary<T>()`, which allows any
+// value of a given type T, i.e.:
+//
+//   FUZZ_TEST(MySuite, CallingMyApiNeverCrashes)
+//     .WithDomains(/*x:*/fuzztest::Arbitrary<int>(),
+//                  /*s:*/fuzztest::Arbitrary<std::string>());
+//
+// then the input domain assignment with `.WithDomains()` can be omitted:
+//
+//   FUZZ_TEST(MySuite, CallingMyApiNeverCrashes);
+//
+// Note: When specifying both the domains and seeds, the domain clause has to
+// be specified first.
+#define FUZZ_TEST(suite_name, func) INTERNAL_FUZZ_TEST(suite_name, func)
+
+// The FUZZ_TEST_F macro registers a fuzz test that uses a test fixture.
+//
+// The first parameter is the name of the fixture class, which is also used as
+// the name of the test suite. The second parameter is the name of the property
+// function (also used as the test name), which must be defined as a public
+// member of the fixture class.
+//
+// A test fixture can be any default-constructible class. The fixture's setup
+// code should be in its constructor, and the teardown code should be in its
+// destructor. While running the fuzz test, which involves calling the property
+// function multiple times with various inputs, the fixture will be instantiated
+// only once at the beginning and destroyed at the end of the fuzz test. In
+// particular, the same instance will be used in all calls to the property
+// function.
+//
+// If the fixture you are using is a GoogleTest fixture (i.e., it extends
+// `::testing::Test`, either directly or indirectly), then you will additionally
+// need to wrap the fixture in an adapter. For more details, see
+// https://github.com/google/fuzztest/blob/main/doc/fixtures.md.
+//
+// Just like the FUZZ_TEST macro, the FUZZ_TEST_F macro allows specifying the
+// domains and seeds using the `.WithDomains()` and `.WithSeeds()` clauses.
+//
+// Example:
+//
+//   class FooFuzzTest {
+//    public:
+//     FooFuzzTest() { foo_.SetUp(); }
+//     ~FooFuzzTest() { foo_.TearDown(); }
+//
+//     void CallingFooBarNeverCrashes(int x, const std::string& s) {
+//       bool result = foo_.Bar(x, s);
+//       ASSERT_TRUE(result);
+//     }
+//
+//    private:
+//     Foo foo_;
+//   };
+//   FUZZ_TEST_F(FooFuzzTest, CallingFooBarNeverCrashes)
+//     .WithDomains(/*x:*/fuzztest::Positive<int>(),
+//                  /*s:*/fuzztest::AsciiString())
+//     .WithSeeds({{5, "Foo"}, {10, "Bar"}});
+//
+#define FUZZ_TEST_F(fixture, func) \
+  INTERNAL_FUZZ_TEST_F(fixture, func, fixture, func)
+
+// Reads files as strings from the directory `dir` and returns a vector usable
+// by .WithSeeds().
+//
+// Example:
+//
+//   void MyThingNeverCrashes(const std::string& s) {
+//     DoThingsWith(s);
+//   }
+//   FUZZ_TEST(MySuite, MyThingNeverCrashes)
+//     .WithSeeds(ReadFilesFromDirectory(kCorpusPath));
+inline std::vector<std::tuple<std::string>> ReadFilesFromDirectory(
+    std::string_view dir) {
+  return internal::ReadFilesFromDirectory({dir.data(), dir.size()});
+}
+
+}  // namespace fuzztest
+
+#endif  // FUZZTEST_FUZZTEST_FUZZTEST_MACROS_H_
diff --git a/fuzztest/internal/io.cc b/fuzztest/internal/io.cc
index f3e4af756..9723d6dc4 100644
--- a/fuzztest/internal/io.cc
+++ b/fuzztest/internal/io.cc
@@ -23,6 +23,7 @@
 #include <sstream>
 #include <string>
 #include <string_view>
+#include <tuple>
 #include <utility>
 #include <vector>
 
@@ -152,4 +153,19 @@ absl::string_view Basename(absl::string_view filename) {
              : filename.substr(last_slash_pos + 1);
 }
 
+std::vector<std::tuple<std::string>> ReadFilesFromDirectory(
+    std::string_view dir) {
+  std::vector<FilePathAndData> files =
+      ReadFileOrDirectory({dir.data(), dir.size()});
+
+  std::vector<std::tuple<std::string>> out;
+  out.reserve(files.size());
+
+  for (const FilePathAndData& file : files) {
+    out.push_back(std::make_tuple(file.data));
+  }
+
+  return out;
+}
+
 }  // namespace fuzztest::internal
diff --git a/fuzztest/internal/io.h b/fuzztest/internal/io.h
index 10668757d..b2f4d9e8d 100644
--- a/fuzztest/internal/io.h
+++ b/fuzztest/internal/io.h
@@ -50,6 +50,11 @@ std::vector<std::string> ListDirectory(absl::string_view dir);
 // Returns the basename of `filename`.
 absl::string_view Basename(absl::string_view filename);
 
+// Reads files as strings from the directory `dir` and returns a vector usable
+// by .WithSeeds().
+std::vector<std::tuple<std::string>> ReadFilesFromDirectory(
+    absl::string_view dir);
+
 }  // namespace fuzztest::internal
 
 #endif  // FUZZTEST_FUZZTEST_INTERNAL_IO_H_
diff --git a/fuzztest/internal/io_test.cc b/fuzztest/internal/io_test.cc
index 98841f138..5b9818b8c 100644
--- a/fuzztest/internal/io_test.cc
+++ b/fuzztest/internal/io_test.cc
@@ -28,7 +28,7 @@
 #include "gmock/gmock.h"
 #include "gtest/gtest.h"
 #include "absl/strings/str_cat.h"
-#include "./fuzztest/fuzztest.h"
+#include "./fuzztest/fuzztest_core.h"
 
 namespace fuzztest::internal {
 namespace {
diff --git a/fuzztest/internal/registration.h b/fuzztest/internal/registration.h
index 62a8c2f60..351b8852f 100644
--- a/fuzztest/internal/registration.h
+++ b/fuzztest/internal/registration.h
@@ -28,7 +28,7 @@
 #include "absl/functional/any_invocable.h"
 #include "absl/strings/str_format.h"
 #include "absl/types/span.h"
-#include "./fuzztest/domain.h"
+#include "./fuzztest/domain_core.h"
 #include "./fuzztest/internal/domains/aggregate_of_impl.h"
 #include "./fuzztest/internal/domains/domain_base.h"
 #include "./fuzztest/internal/meta.h"
diff --git a/fuzztest/internal/runtime.h b/fuzztest/internal/runtime.h
index 541ffb0e1..3149f7b2f 100644
--- a/fuzztest/internal/runtime.h
+++ b/fuzztest/internal/runtime.h
@@ -37,7 +37,7 @@
 #include "absl/strings/string_view.h"
 #include "absl/time/time.h"
 #include "absl/types/span.h"
-#include "./fuzztest/domain.h"
+#include "./fuzztest/domain_core.h"
 #include "./fuzztest/internal/configuration.h"
 #include "./fuzztest/internal/coverage.h"
 #include "./fuzztest/internal/fixture_driver.h"
diff --git a/fuzztest/internal/runtime_test.cc b/fuzztest/internal/runtime_test.cc
index 0fbbad947..e8e0a8e92 100644
--- a/fuzztest/internal/runtime_test.cc
+++ b/fuzztest/internal/runtime_test.cc
@@ -20,7 +20,7 @@
 
 #include "gtest/gtest.h"
 #include "absl/time/time.h"
-#include "./fuzztest/domain.h"
+#include "./fuzztest/domain_core.h"
 #include "./fuzztest/internal/test_protobuf.pb.h"
 
 namespace fuzztest::internal {