diff --git a/Makefile b/Makefile
index 5bf05a8a..fd2cfa99 100644
--- a/Makefile
+++ b/Makefile
@@ -62,10 +62,10 @@ SRCHEADERS_GENERIC=src/generic/numberparsing.h src/generic/stage1_find_marks.h s
 SRCHEADERS_ARM64=      src/arm64/bitmanipulation.h    src/arm64/bitmask.h    src/arm64/intrinsics.h    src/arm64/numberparsing.h    src/arm64/simd.h    src/arm64/stage1_find_marks.h    src/arm64/stage2_build_tape.h    src/arm64/stringparsing.h
 SRCHEADERS_HASWELL=  src/haswell/bitmanipulation.h  src/haswell/bitmask.h  src/haswell/intrinsics.h  src/haswell/numberparsing.h  src/haswell/simd.h  src/haswell/stage1_find_marks.h  src/haswell/stage2_build_tape.h  src/haswell/stringparsing.h
 SRCHEADERS_WESTMERE=src/westmere/bitmanipulation.h src/westmere/bitmask.h src/westmere/intrinsics.h src/westmere/numberparsing.h src/westmere/simd.h src/westmere/stage1_find_marks.h src/westmere/stage2_build_tape.h src/westmere/stringparsing.h
-SRCHEADERS_SRC=src/jsoncharutils.h src/simdprune_tables.h src/error.cpp src/jsonioutil.cpp src/implementation.cpp src/stage1_find_marks.cpp src/stage2_build_tape.cpp src/inline/document_parser_callbacks.h
+SRCHEADERS_SRC=src/isadetection.h src/jsoncharutils.h src/simdprune_tables.h src/error.cpp src/jsonioutil.cpp src/implementation.cpp src/stage1_find_marks.cpp src/stage2_build_tape.cpp src/inline/document_parser_callbacks.h
 SRCHEADERS=$(SRCHEADERS_SRC) $(SRCHEADERS_GENERIC) $(SRCHEADERS_ARM64) $(SRCHEADERS_HASWELL) $(SRCHEADERS_WESTMERE)
 
-INCLUDEHEADERS=include/simdjson.h include/simdjson/common_defs.h include/simdjson/isadetection.h include/simdjson/jsonformatutils.h include/simdjson/jsonioutil.h include/simdjson/jsonminifier.h include/simdjson/jsonparser.h include/simdjson/padded_string.h include/simdjson/document.h include/simdjson/inline/document.h include/simdjson/document_iterator.h include/simdjson/inline/document_iterator.h include/simdjson/implementation.h include/simdjson/parsedjson.h include/simdjson/jsonstream.h include/simdjson/portability.h include/simdjson/error.h include/simdjson/simdjson.h include/simdjson/simdjson_version.h
+INCLUDEHEADERS=include/simdjson.h include/simdjson/common_defs.h include/simdjson/internal/jsonformatutils.h include/simdjson/jsonioutil.h include/simdjson/jsonminifier.h include/simdjson/jsonparser.h include/simdjson/padded_string.h include/simdjson/document.h include/simdjson/inline/document.h include/simdjson/document_iterator.h include/simdjson/inline/document_iterator.h include/simdjson/implementation.h include/simdjson/parsedjson.h include/simdjson/jsonstream.h include/simdjson/portability.h include/simdjson/error.h include/simdjson/simdjson.h include/simdjson/simdjson_version.h
 
 ifeq ($(SIMDJSON_TEST_AMALGAMATED_HEADERS),1)
 	HEADERS=singleheader/simdjson.h
diff --git a/include/CMakeLists.txt b/include/CMakeLists.txt
index 5413eab1..607e74f4 100644
--- a/include/CMakeLists.txt
+++ b/include/CMakeLists.txt
@@ -8,8 +8,7 @@ set(SIMDJSON_INCLUDE
     ${SIMDJSON_INCLUDE_DIR}/simdjson/implementation.h
     ${SIMDJSON_INCLUDE_DIR}/simdjson/inline/document.h
     ${SIMDJSON_INCLUDE_DIR}/simdjson/inline/document_iterator.h
-    ${SIMDJSON_INCLUDE_DIR}/simdjson/isadetection.h
-    ${SIMDJSON_INCLUDE_DIR}/simdjson/jsonformatutils.h
+    ${SIMDJSON_INCLUDE_DIR}/simdjson/internal/jsonformatutils.h
     ${SIMDJSON_INCLUDE_DIR}/simdjson/jsonioutil.h
     ${SIMDJSON_INCLUDE_DIR}/simdjson/jsonminifier.h
     ${SIMDJSON_INCLUDE_DIR}/simdjson/jsonparser.h
diff --git a/include/simdjson/document_iterator.h b/include/simdjson/document_iterator.h
index 18b69752..bf005538 100644
--- a/include/simdjson/document_iterator.h
+++ b/include/simdjson/document_iterator.h
@@ -9,7 +9,7 @@
 #include <stdexcept>
 
 #include "simdjson/document.h"
-#include "simdjson/jsonformatutils.h"
+#include "simdjson/internal/jsonformatutils.h"
 
 namespace simdjson {
 
diff --git a/include/simdjson/inline/document.h b/include/simdjson/inline/document.h
index 1d39ccd1..63938ee1 100644
--- a/include/simdjson/inline/document.h
+++ b/include/simdjson/inline/document.h
@@ -1,15 +1,13 @@
 #ifndef SIMDJSON_INLINE_DOCUMENT_H
 #define SIMDJSON_INLINE_DOCUMENT_H
 
-
-// Inline implementations go in here if they aren't small enough to go in the class itself or if
-// there are complex header file dependencies that need to be broken by externalizing the
-// implementation.
+// Inline implementations go in here.
 
 #include "simdjson/document.h"
 #include "simdjson/implementation.h"
-#include "simdjson/jsonformatutils.h"
+#include "simdjson/internal/jsonformatutils.h"
 #include <iostream>
+
 namespace simdjson {
 
 //
@@ -278,7 +276,7 @@ inline bool document::print_json(std::ostream &os, size_t max_depth) const noexc
     case '"': // we have a string
       os << '"';
       memcpy(&string_length, string_buf.get() + payload, sizeof(uint32_t));
-      print_with_escapes(
+      internal::print_with_escapes(
           (const unsigned char *)(string_buf.get() + payload + sizeof(uint32_t)),
           os, string_length);
       os << '"';
@@ -368,7 +366,7 @@ inline bool document::dump_raw_tape(std::ostream &os) const noexcept {
     case '"': // we have a string
       os << "string \"";
       memcpy(&string_length, string_buf.get() + payload, sizeof(uint32_t));
-      print_with_escapes(
+      internal::print_with_escapes(
           (const unsigned char *)(string_buf.get() + payload + sizeof(uint32_t)),
                   os,
           string_length);
diff --git a/include/simdjson/inline/document_iterator.h b/include/simdjson/inline/document_iterator.h
index 9d86ec4f..59734ff2 100644
--- a/include/simdjson/inline/document_iterator.h
+++ b/include/simdjson/inline/document_iterator.h
@@ -276,7 +276,7 @@ bool document_iterator<max_depth>::print(std::ostream &os, bool escape_strings)
   case '"': // we have a string
     os << '"';
     if (escape_strings) {
-      print_with_escapes(get_string(), os, get_string_length());
+      internal::print_with_escapes(get_string(), os, get_string_length());
     } else {
       // was: os << get_string();, but given that we can include null chars, we
       // have to do something crazier:
diff --git a/include/simdjson/jsonformatutils.h b/include/simdjson/internal/jsonformatutils.h
similarity index 87%
rename from include/simdjson/jsonformatutils.h
rename to include/simdjson/internal/jsonformatutils.h
index 3a5e75e8..8c6187b2 100644
--- a/include/simdjson/jsonformatutils.h
+++ b/include/simdjson/internal/jsonformatutils.h
@@ -1,15 +1,13 @@
-#ifndef SIMDJSON_JSONFORMATUTILS_H
-#define SIMDJSON_JSONFORMATUTILS_H
+#ifndef SIMDJSON_INTERNAL_JSONFORMATUTILS_H
+#define SIMDJSON_INTERNAL_JSONFORMATUTILS_H
 
 #include <iomanip>
 #include <iostream>
 
-namespace simdjson {
-
+namespace simdjson::internal {
 
 // ends with zero char
-static inline void print_with_escapes(const unsigned char *src,
-                                      std::ostream &os) {
+static inline void print_with_escapes(const unsigned char *src, std::ostream &os) {
   while (*src) {
     switch (*src) {
     case '\b':
@@ -107,10 +105,10 @@ static inline void print_with_escapes(const char *src, std::ostream &os) {
   print_with_escapes(reinterpret_cast<const unsigned char *>(src), os);
 }
 
-static inline void print_with_escapes(const char *src, std::ostream &os,
-                                      size_t len) {
+static inline void print_with_escapes(const char *src, std::ostream &os, size_t len) {
   print_with_escapes(reinterpret_cast<const unsigned char *>(src), os, len);
 }
-} // namespace simdjson
 
-#endif
+} // namespace simdjson::internal
+
+#endif // SIMDJSON_INTERNAL_JSONFORMATUTILS_H
diff --git a/include/simdjson/jsonstream.h b/include/simdjson/jsonstream.h
index a8824cbd..d5989c81 100644
--- a/include/simdjson/jsonstream.h
+++ b/include/simdjson/jsonstream.h
@@ -5,7 +5,6 @@
 #include <limits>
 #include <stdexcept>
 #include <thread>
-#include "simdjson/isadetection.h"
 #include "simdjson/padded_string.h"
 #include "simdjson/simdjson.h"
 #include "jsoncharutils.h"
diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 26eb2d81..964af7f1 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -29,6 +29,7 @@ set(SIMDJSON_SRC
 set(SIMDJSON_SRC_HEADERS
   error.cpp
   implementation.cpp
+  isadetection.h
   jsoncharutils.h
   jsonioutil.cpp
   jsonminifier.cpp
diff --git a/src/arm64/implementation.h b/src/arm64/implementation.h
index 7380c5d2..0f6d7644 100644
--- a/src/arm64/implementation.h
+++ b/src/arm64/implementation.h
@@ -6,7 +6,7 @@
 #ifdef IS_ARM64
 
 #include "simdjson/implementation.h"
-#include "simdjson/isadetection.h"
+#include "isadetection.h"
 
 namespace simdjson::arm64 {
 
diff --git a/src/haswell/implementation.h b/src/haswell/implementation.h
index 55b55599..8bb9f5cd 100644
--- a/src/haswell/implementation.h
+++ b/src/haswell/implementation.h
@@ -6,7 +6,7 @@
 #ifdef IS_X86_64
 
 #include "simdjson/implementation.h"
-#include "simdjson/isadetection.h"
+#include "isadetection.h"
 
 namespace simdjson::haswell {
 
diff --git a/src/implementation.cpp b/src/implementation.cpp
index cbba5dee..652c8dcb 100644
--- a/src/implementation.cpp
+++ b/src/implementation.cpp
@@ -1,5 +1,5 @@
 #include "simdjson/portability.h"
-#include "simdjson/isadetection.h"
+#include "isadetection.h"
 #include "simdjson/implementation.h"
 #include <initializer_list>
 
@@ -11,10 +11,10 @@
 #include "haswell/implementation.h"
 #include "westmere/implementation.h"
 
-namespace simdjson {
-  const haswell::implementation haswell_singleton{};
-  const westmere::implementation westmere_singleton{};
-  constexpr const std::initializer_list<const implementation *> available_implementation_pointers { &haswell_singleton, &westmere_singleton };
+namespace simdjson::internal {
+const haswell::implementation haswell_singleton{};
+const westmere::implementation westmere_singleton{};
+constexpr const std::initializer_list<const implementation *> available_implementation_pointers { &haswell_singleton, &westmere_singleton };
 }
 
 #endif
@@ -23,19 +23,20 @@ namespace simdjson {
 
 #include "arm64/implementation.h"
 
-namespace simdjson {
-  const arm64::implementation arm64_singleton{};
-  constexpr const std::initializer_list<const implementation *> available_implementation_pointers { &arm64_singleton };
+namespace simdjson::internal {
+const arm64::implementation arm64_singleton{};
+constexpr const std::initializer_list<const implementation *> available_implementation_pointers { &arm64_singleton };
 }
 
 #endif
 
-namespace simdjson {
+
+namespace simdjson::internal {
 
 // So we can return UNSUPPORTED_ARCHITECTURE from the parser when there is no support
 class unsupported_implementation final : public implementation {
 public:
-  WARN_UNUSED virtual error_code parse(const uint8_t *, size_t, document::parser &) const noexcept final {
+  WARN_UNUSED error_code parse(const uint8_t *, size_t, document::parser &) const noexcept final {
     return UNSUPPORTED_ARCHITECTURE;
   }
   WARN_UNUSED error_code stage1(const uint8_t *, size_t, document::parser &, bool) const noexcept final {
@@ -53,21 +54,19 @@ public:
 
 const unsupported_implementation unsupported_singleton{};
 
-namespace internal {
-
 size_t available_implementation_list::size() const noexcept {
-  return available_implementation_pointers.size();
+  return internal::available_implementation_pointers.size();
 }
 const implementation * const *available_implementation_list::begin() const noexcept {
-  return available_implementation_pointers.begin();
+  return internal::available_implementation_pointers.begin();
 }
 const implementation * const *available_implementation_list::end() const noexcept {
-  return available_implementation_pointers.end();
+  return internal::available_implementation_pointers.end();
 }
 const implementation *available_implementation_list::detect_best_supported() const noexcept {
   // They are prelisted in priority order, so we just go down the list
   uint32_t supported_instruction_sets = detect_supported_architectures();
-  for (const implementation *impl : available_implementation_pointers) {
+  for (const implementation *impl : internal::available_implementation_pointers) {
     uint32_t required_instruction_sets = impl->required_instruction_sets();
     if ((supported_instruction_sets & required_instruction_sets) == required_instruction_sets) { return impl; }
   }
@@ -78,6 +77,4 @@ const implementation *detect_best_supported_implementation_on_first_use::set_bes
   return active_implementation = available_implementations.detect_best_supported();
 }
 
-} // namespace simdjson::internal
-
 } // namespace simdjson
diff --git a/include/simdjson/isadetection.h b/src/isadetection.h
similarity index 98%
rename from include/simdjson/isadetection.h
rename to src/isadetection.h
index 328df291..c881c85f 100644
--- a/include/simdjson/isadetection.h
+++ b/src/isadetection.h
@@ -55,6 +55,7 @@ POSSIBILITY OF SUCH DAMAGE.
 #endif
 
 namespace simdjson {
+
 // Can be found on Intel ISA Reference for CPUID
 constexpr uint32_t cpuid_avx2_bit = 1 << 5;      // Bit 5 of EBX for EAX=0x7
 constexpr uint32_t cpuid_bmi1_bit = 1 << 3;      // bit 3 of EBX for EAX=0x7
@@ -148,5 +149,7 @@ static inline uint32_t detect_supported_architectures() {
 }
 
 #endif // end SIMD extension detection code
-} // namespace simdjson
-#endif
+
+} // namespace simdjson::internal
+
+#endif // SIMDJSON_ISADETECTION_H
diff --git a/src/westmere/implementation.h b/src/westmere/implementation.h
index b6b8c681..a992152c 100644
--- a/src/westmere/implementation.h
+++ b/src/westmere/implementation.h
@@ -6,7 +6,7 @@
 #ifdef IS_X86_64
 
 #include "simdjson/implementation.h"
-#include "simdjson/isadetection.h"
+#include "isadetection.h"
 
 namespace simdjson::westmere {