diff --git a/CMakeLists.txt b/CMakeLists.txt
index 8c6845cb..fdcfc4a8 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -90,6 +90,7 @@ option(ENABLE_LTO "Enable link-time optimization" OFF)
 option(FAST_FLOAT "Enable float for LSTM" ON)
 option(ENABLE_OPENCL "Enable unsupported experimental OpenCL support" OFF)
 option(BUILD_TRAINING_TOOLS "Build training tools" ON)
+option(BUILD_TESSERACT_BINARY "Build Tesseract binary" ON)
 option(BUILD_TESTS "Build tests" OFF)
 option(USE_SYSTEM_ICU "Use system ICU" OFF)
 option(DISABLE_ARCHIVE "Disable build with libarchive (if available)" OFF)
@@ -565,9 +566,7 @@ file(
   src/cutil/*.cpp
   src/dict/*.cpp
   src/lstm/*.cpp
-  src/opencl/*.cpp
   src/textord/*.cpp
-  src/viewer/*.cpp
   src/wordrec/*.cpp)

 if(DISABLED_LEGACY_ENGINE)
@@ -714,13 +713,7 @@ file(
 set(TESSERACT_SRC
     ${TESSERACT_SRC}
     src/api/baseapi.cpp
-    src/api/capi.cpp
-    src/api/renderer.cpp
-    src/api/altorenderer.cpp
-    src/api/hocrrenderer.cpp
-    src/api/lstmboxrenderer.cpp
-    src/api/pdfrenderer.cpp
-    src/api/wordstrboxrenderer.cpp)
+    src/api/hocrrenderer.cpp)

 set(TESSERACT_CONFIGS
   tessdata/configs/alto
@@ -858,14 +851,16 @@ endif()
 # EXECUTABLE tesseract
 # ##############################################################################

-add_executable(tesseract src/tesseract.cpp)
-target_link_libraries(tesseract libtesseract)
-if(HAVE_TIFFIO_H AND WIN32)
-  target_link_libraries(tesseract ${TIFF_LIBRARIES})
-endif()
+if(BUILD_TESSERACT_BINARY)
+  add_executable(tesseract src/tesseract.cpp)
+  target_link_libraries(tesseract libtesseract)
+  if(HAVE_TIFFIO_H AND WIN32)
+    target_link_libraries(tesseract ${TIFF_LIBRARIES})
+  endif()

-if(OPENMP_BUILD AND UNIX)
-  target_link_libraries(tesseract pthread)
+  if(OPENMP_BUILD AND UNIX)
+    target_link_libraries(tesseract pthread)
+  endif()
 endif()

 # ##############################################################################
@@ -899,7 +894,11 @@ write_basic_package_version_file(

 install(FILES ${CMAKE_CURRENT_BINARY_DIR}/tesseract.pc
         DESTINATION ${CMAKE_INSTALL_LIBDIR}/pkgconfig)
-install(TARGETS tesseract DESTINATION bin)
+
+if(BUILD_TESSERACT_BINARY)
+  install(TARGETS tesseract DESTINATION bin)
+endif()
+
 install(
   TARGETS libtesseract
   EXPORT TesseractTargets
diff --git a/src/arch/simddetect.cpp b/src/arch/simddetect.cpp
index 1afe5a5d..cb8c6d4c 100644
--- a/src/arch/simddetect.cpp
+++ b/src/arch/simddetect.cpp
@@ -40,10 +40,12 @@

 #endif

+#if !defined(__wasm__)
 #if defined(HAVE_AVX) || defined(HAVE_AVX2) || defined(HAVE_FMA) || defined(HAVE_SSE4_1)
 // See https://en.wikipedia.org/wiki/CPUID.
 #  define HAS_CPUID
 #endif
+#endif

 #if defined(HAS_CPUID)
 #  if defined(__GNUC__)
diff --git a/src/ccmain/pageiterator.cpp b/src/ccmain/pageiterator.cpp
index 64ff7f66..c0f80e5f 100644
--- a/src/ccmain/pageiterator.cpp
+++ b/src/ccmain/pageiterator.cpp
@@ -582,7 +582,9 @@ void PageIterator::Orientation(tesseract::Orientation *orientation,
   up_in_image.rotate(block->re_rotation());

   if (up_in_image.x() == 0.0F) {
-    if (up_in_image.y() > 0.0F) {
+    // tesseract-wasm note: `up_in_image` will be a null vector if orientation
+    // info is not available. In that case, assume page up.
+    if (up_in_image.y() >= 0.0F) {
       *orientation = ORIENTATION_PAGE_UP;
     } else {
       *orientation = ORIENTATION_PAGE_DOWN;
diff --git a/src/ccmain/pagesegmain.cpp b/src/ccmain/pagesegmain.cpp
index 0af44607..718e73ef 100644
--- a/src/ccmain/pagesegmain.cpp
+++ b/src/ccmain/pagesegmain.cpp
@@ -222,7 +222,7 @@ int Tesseract::AutoPageSeg(PageSegMode pageseg_mode, BLOCK_LIST *blocks, TO_BLOC
     }
 #endif // ndef DISABLED_LEGACY_ENGINE
     result = finder->FindBlocks(pageseg_mode, scaled_color_, scaled_factor_, to_block,
-                                photomask_pix, pix_thresholds_, pix_grey_, &pixa_debug_,
+                                photomask_pix, pix_thresholds_, pix_grey_, pixa_debug_.get(),
                                 &found_blocks, diacritic_blobs, to_blocks);
     if (result >= 0) {
       finder->GetDeskewVectors(&deskew_, &reskew_);
@@ -279,17 +279,17 @@ ColumnFinder *Tesseract::SetupPageSegAndDetectOrientation(PageSegMode pageseg_mo
   ICOORD bleft(0, 0);

   ASSERT_HOST(pix_binary_ != nullptr);
-  if (tessedit_dump_pageseg_images) {
-    pixa_debug_.AddPix(pix_binary_, "PageSegInput");
+  if (tessedit_dump_pageseg_images && pixa_debug_) {
+    pixa_debug_->AddPix(pix_binary_, "PageSegInput");
   }
   // Leptonica is used to find the rule/separator lines in the input.
   LineFinder::FindAndRemoveLines(source_resolution_, textord_tabfind_show_vlines, pix_binary_,
                                  &vertical_x, &vertical_y, music_mask_pix, &v_lines, &h_lines);
-  if (tessedit_dump_pageseg_images) {
-    pixa_debug_.AddPix(pix_binary_, "NoLines");
+  if (tessedit_dump_pageseg_images && pixa_debug_) {
+    pixa_debug_->AddPix(pix_binary_, "NoLines");
   }
   // Leptonica is used to find a mask of the photo regions in the input.
-  *photo_mask_pix = ImageFind::FindImages(pix_binary_, &pixa_debug_);
+  *photo_mask_pix = ImageFind::FindImages(pix_binary_, pixa_debug_.get());
   if (tessedit_dump_pageseg_images) {
     Image pix_no_image_ = nullptr;
     if (*photo_mask_pix != nullptr) {
@@ -297,7 +297,7 @@ ColumnFinder *Tesseract::SetupPageSegAndDetectOrientation(PageSegMode pageseg_mo
     } else {
       pix_no_image_ = pix_binary_.clone();
     }
-    pixa_debug_.AddPix(pix_no_image_, "NoImages");
+    pixa_debug_->AddPix(pix_no_image_, "NoImages");
     pix_no_image_.destroy();
   }
   if (!PSM_COL_FIND_ENABLED(pageseg_mode)) {
diff --git a/src/ccmain/tesseractclass.cpp b/src/ccmain/tesseractclass.cpp
index fd58ac87..517f925e 100644
--- a/src/ccmain/tesseractclass.cpp
+++ b/src/ccmain/tesseractclass.cpp
@@ -487,8 +487,10 @@ Dict &Tesseract::getDict() {
 }

 void Tesseract::Clear() {
-  std::string debug_name = imagebasename + "_debug.pdf";
-  pixa_debug_.WritePDF(debug_name.c_str());
+  if (pixa_debug_) {
+    std::string debug_name = imagebasename + "_debug.pdf";
+    pixa_debug_->WritePDF(debug_name.c_str());
+  }
   pix_binary_.destroy();
   pix_grey_.destroy();
   pix_thresholds_.destroy();
@@ -572,7 +574,7 @@ void Tesseract::PrepareForPageseg() {
   // the newly split image.
   splitter_.set_orig_pix(pix_binary());
   splitter_.set_pageseg_split_strategy(max_pageseg_strategy);
-  if (splitter_.Split(true, &pixa_debug_)) {
+  if (splitter_.Split(true, pixa_debug_.get())) {
     ASSERT_HOST(splitter_.splitted_image());
     pix_binary_.destroy();
     pix_binary_ = splitter_.splitted_image().clone();
@@ -599,7 +601,7 @@ void Tesseract::PrepareForTessOCR(BLOCK_LIST *block_list, Tesseract *osd_tess, O
   splitter_.set_segmentation_block_list(block_list);
   splitter_.set_ocr_split_strategy(max_ocr_strategy);
   // Run the splitter for OCR
-  bool split_for_ocr = splitter_.Split(false, &pixa_debug_);
+  bool split_for_ocr = splitter_.Split(false, pixa_debug_.get());
   // Restore pix_binary to the binarized original pix for future reference.
   ASSERT_HOST(splitter_.orig_pix());
   pix_binary_.destroy();
diff --git a/src/ccmain/tesseractclass.h b/src/ccmain/tesseractclass.h
index 732bb9e6..030aa5bc 100644
--- a/src/ccmain/tesseractclass.h
+++ b/src/ccmain/tesseractclass.h
@@ -986,7 +986,7 @@ private:
   // Thresholds that were used to generate the thresholded image from grey.
   Image pix_thresholds_;
   // Debug images. If non-empty, will be written on destruction.
-  DebugPixa pixa_debug_;
+  std::unique_ptr<DebugPixa> pixa_debug_;
   // Input image resolution after any scaling. The resolution is not well
   // transmitted by operations on Pix, so we keep an independent record here.
   int source_resolution_;