diff --git a/g2o/apps/g2o_viewer/main_window.cpp b/g2o/apps/g2o_viewer/main_window.cpp
index e003d3629..6f62c1c37 100644
--- a/g2o/apps/g2o_viewer/main_window.cpp
+++ b/g2o/apps/g2o_viewer/main_window.cpp
@@ -22,9 +22,11 @@
 #include <QDoubleValidator>
 #include <QFileDialog>
 #include <QStandardItemModel>
+#include <algorithm>
 #include <cassert>
 #include <fstream>
 #include <iostream>
+#include <iterator>
 #include <string>
 
 #include "g2o/core/estimate_propagator.h"
@@ -40,10 +42,56 @@
 #include "properties_widget.h"
 #include "viewer_properties_widget.h"
 
+namespace {
+/**
+ * @brief Join into a string using a delimeter
+ *
+ * @tparam Iterator
+ * @tparam std::iterator_traits<Iterator>::value_type
+ * @param b begin of the range for output
+ * @param e end of the range for output
+ * @param delimiter will be inserted in between elements
+ * @return std::string joined string
+ */
+template <typename Iterator,
+          typename Value = typename std::iterator_traits<Iterator>::value_type>
+std::string strJoin(Iterator b, Iterator e, const std::string& delimiter) {
+  std::ostringstream os;
+  if (b != e) {
+    std::copy(b, std::prev(e),
+              std::ostream_iterator<Value>(os, delimiter.c_str()));
+    b = std::prev(e);
+  }
+  if (b != e) {
+    os << *b;
+  }
+  return os.str();
+}
+
+QString prepareFilter(const std::vector<g2o::io::FileFilter>& filters) {
+  std::vector<std::string> filter_patterns;
+  filter_patterns.reserve(filters.size());
+  std::transform(filters.begin(), filters.end(),
+                 std::back_inserter(filter_patterns),
+                 [](const g2o::io::FileFilter& f) { return f.filter; });
+  return QString::fromStdString(
+      strJoin(filter_patterns.begin(), filter_patterns.end(), ";;"));
+}
+
+g2o::io::Format extractFileFormat(
+    const std::vector<g2o::io::FileFilter>& filters,
+    const std::string& file_pattern) {
+  for (const auto& f : filters) {
+    if (f.filter == file_pattern) return f.format;
+  }
+  return g2o::io::Format::kUndefined;
+}
+}  // namespace
+
 MainWindow::MainWindow(QWidget* parent) : QMainWindow(parent) {
   setupUi(this);
   leKernelWidth->setValidator(
-      new QDoubleValidator(-std::numeric_limits<double>::max(),
+      new QDoubleValidator(std::numeric_limits<double>::lowest(),
                            std::numeric_limits<double>::max(), 7, this));
   plainTextEdit->setMaximumBlockCount(1000);
   btnForceStop->hide();
@@ -52,19 +100,34 @@ MainWindow::MainWindow(QWidget* parent) : QMainWindow(parent) {
 }
 
 void MainWindow::on_actionLoad_triggered(bool) {
+  const std::vector<g2o::io::FileFilter> file_filters =
+      g2o::io::getFileFilter(true /*open*/);
+  QString selectedFilter;
   const QString filename = QFileDialog::getOpenFileName(
-      this, "Load g2o file", "", "g2o files (*.g2o);;All Files (*)");
+      this, "Load g2o file", "", prepareFilter(file_filters), &selectedFilter);
   if (!filename.isNull()) {
-    loadFromFile(filename);
+    const g2o::io::Format file_format =
+        extractFileFormat(file_filters, selectedFilter.toStdString());
+    G2O_DEBUG("Selected filter {} with format {}", selectedFilter.toStdString(),
+              g2o::io::to_string(file_format));
+    loadFromFile(filename, file_format);
   }
 }
 
 void MainWindow::on_actionSave_triggered(bool) {
+  const std::vector<g2o::io::FileFilter> file_filters =
+      g2o::io::getFileFilter(false /*open*/);
+  QString selectedFilter;
+
   const QString filename = QFileDialog::getSaveFileName(
-      this, "Save g2o file", "", "g2o files (*.g2o)");
+      this, "Save g2o file", "", prepareFilter(file_filters), &selectedFilter);
   if (!filename.isNull()) {
+    const g2o::io::Format file_format =
+        extractFileFormat(file_filters, selectedFilter.toStdString());
+    G2O_DEBUG("Selected filter {} with format {}", selectedFilter.toStdString(),
+              g2o::io::to_string(file_format));
     std::ofstream fout(filename.toStdString().c_str());
-    viewer->graph->save(fout);
+    viewer->graph->save(fout, file_format);
     if (fout.good())
       std::cerr << "Saved " << filename.toStdString() << '\n';
     else
@@ -217,18 +280,20 @@ void MainWindow::updateDisplayedSolvers() {
   }
 }
 
-bool MainWindow::load(const QString& filename) {
+bool MainWindow::load(const QString& filename, g2o::io::Format format) {
   viewer->graph->clear();
   bool loadStatus = false;
   if (filename == "-") {
     std::cerr << "reading stdin\n";
-    loadStatus = viewer->graph->load(std::cin);
+    loadStatus = viewer->graph->load(std::cin, format);
   } else {
     const std::string filename_as_std = filename.toStdString();
     const std::string filename_extension =
         g2o::getFileExtension(filename_as_std);
-    std::optional<g2o::io::Format> file_format =
-        g2o::io::formatForFileExtension(filename_extension);
+    const std::optional<g2o::io::Format> file_format =
+        format != g2o::io::Format::kUndefined
+            ? format
+            : g2o::io::formatForFileExtension(filename_extension);
     std::ifstream ifs(filename_as_std);
     if (!ifs) return false;
     loadStatus = file_format.has_value()
@@ -346,9 +411,9 @@ void MainWindow::setRobustKernel() {
 
 void MainWindow::on_btnForceStop_clicked() { forceStopFlag_ = true; }
 
-bool MainWindow::loadFromFile(const QString& filename) {
+bool MainWindow::loadFromFile(const QString& filename, g2o::io::Format format) {
   viewer->graph->clear();
-  bool loadStatus = load(filename);
+  bool loadStatus = load(filename, format);
   if (loadStatus) {
     filename_ = filename.toStdString();
   }
diff --git a/g2o/apps/g2o_viewer/main_window.h b/g2o/apps/g2o_viewer/main_window.h
index e16561ae6..18d28bf7a 100644
--- a/g2o/apps/g2o_viewer/main_window.h
+++ b/g2o/apps/g2o_viewer/main_window.h
@@ -21,6 +21,7 @@
 
 #include <vector>
 
+#include "g2o/core/io/io_format.h"
 #include "g2o/core/optimization_algorithm_property.h"
 #include "g2o_viewer_api.h"
 #include "ui_base_main_window.h"
@@ -56,7 +57,8 @@ class G2O_VIEWER_API MainWindow : public QMainWindow,
   /**
    * load a graph on which we will operate from a file
    */
-  bool loadFromFile(const QString& filename);
+  bool loadFromFile(const QString& filename,
+                    g2o::io::Format format = g2o::io::Format::kUndefined);
 
  public slots:  // NOLINT
   void on_actionLoad_triggered(bool);
@@ -80,7 +82,8 @@ class G2O_VIEWER_API MainWindow : public QMainWindow,
   bool allocateSolver(bool& allocatedNewSolver);
   bool prepare();
   void setRobustKernel();
-  bool load(const QString& filename);
+  bool load(const QString& filename,
+            g2o::io::Format format = g2o::io::Format::kUndefined);
 
   std::vector<g2o::OptimizationAlgorithmProperty> knownSolvers_;
   int lastSolver_ = -1;
diff --git a/g2o/core/abstract_graph.cpp b/g2o/core/abstract_graph.cpp
index e78a95d2c..013eb09b3 100644
--- a/g2o/core/abstract_graph.cpp
+++ b/g2o/core/abstract_graph.cpp
@@ -37,22 +37,6 @@
 #include "io/io_g2o.h"
 
 namespace {
-#ifdef G2O_HAVE_LOGGING
-std::string_view to_string(g2o::io::Format format) {
-  switch (format) {
-    case g2o::io::Format::kG2O:
-      return "G2O";
-    case g2o::io::Format::kBinary:
-      return "Binary";
-    case g2o::io::Format::kJson:
-      return "JSON";
-    case g2o::io::Format::kXML:
-      return "XML";
-  }
-  return "";
-}
-#endif
-
 /**
  * @brief Allocate an g2o::IoInterface to load/save data of the graph.
  *
@@ -61,6 +45,9 @@ std::string_view to_string(g2o::io::Format format) {
  */
 std::unique_ptr<g2o::IoInterface> allocate(g2o::io::Format format) {
   switch (format) {
+    case g2o::io::Format::kUndefined:
+      G2O_WARN("Cannot allocate IO interface for undefined format");
+      return nullptr;
     case g2o::io::Format::kG2O:
       return std::make_unique<g2o::IoG2O>();
     case g2o::io::Format::kBinary:
@@ -71,7 +58,7 @@ std::unique_ptr<g2o::IoInterface> allocate(g2o::io::Format format) {
       return std::make_unique<g2o::IoXml>();
   }
   G2O_CRITICAL("Failed to create graph IO interface for format {}",
-               to_string(format));
+               g2o::io::to_string(format));
   return nullptr;
 }
 
diff --git a/g2o/core/io/io_format.cpp b/g2o/core/io/io_format.cpp
index d585b65a3..b0a5f8121 100644
--- a/g2o/core/io/io_format.cpp
+++ b/g2o/core/io/io_format.cpp
@@ -31,6 +31,22 @@
 
 namespace g2o::io {
 
+std::string_view to_string(g2o::io::Format format) {
+  switch (format) {
+    case g2o::io::Format::kUndefined:
+      return "Undefined";
+    case g2o::io::Format::kG2O:
+      return "G2O";
+    case g2o::io::Format::kBinary:
+      return "Binary";
+    case g2o::io::Format::kJson:
+      return "JSON";
+    case g2o::io::Format::kXML:
+      return "XML";
+  }
+  return "";
+}
+
 std::optional<Format> formatForFileExtension(std::string_view extension) {
   if (extension == "g2o" || extension == "G2O") return Format::kG2O;
   if (extension == "json" || extension == "JSON") return Format::kJson;
@@ -39,4 +55,23 @@ std::optional<Format> formatForFileExtension(std::string_view extension) {
   return std::nullopt;
 }
 
+FileFilter::FileFilter(std::string filter, Format format)
+    : filter(std::move(filter)), format(format) {}
+
+bool FileFilter::operator==(const FileFilter& other) const {
+  return filter == other.filter && format == other.format;
+}
+
+std::vector<FileFilter> getFileFilter(bool open) {
+  std::vector<FileFilter> result;
+  result.emplace_back("g2o Ascii files (*.g2o)", Format::kG2O);
+  result.emplace_back("g2o Json files (*.json)", Format::kJson);
+  result.emplace_back("g2o XML files (*.xml)", Format::kXML);
+  result.emplace_back("g2o BIN files (*.bin)", Format::kBinary);
+  if (open) {
+    result.emplace_back("All Files (*)", Format::kUndefined);
+  }
+  return result;
+}
+
 }  // namespace g2o::io
diff --git a/g2o/core/io/io_format.h b/g2o/core/io/io_format.h
index 3323bf706..fdefb6e6f 100644
--- a/g2o/core/io/io_format.h
+++ b/g2o/core/io/io_format.h
@@ -28,12 +28,33 @@
 #define G2O_CORE_IO_FORMAT_H
 
 #include <optional>
+#include <string>
 #include <string_view>
+#include <vector>
 
 #include "g2o/core/g2o_core_api.h"
 namespace g2o::io {
 
-enum class G2O_CORE_API Format { kG2O = 0, kBinary = 1, kJson = 2, kXML = 3 };
+enum class G2O_CORE_API Format {
+  kUndefined = -1,
+  kG2O = 0,
+  kBinary = 1,
+  kJson = 2,
+  kXML = 3
+};
+
+G2O_CORE_API std::string_view to_string(g2o::io::Format format);
+
+/**
+ * @brief FileFilter information for Open/Save Dialog
+ *
+ */
+struct G2O_CORE_API FileFilter {
+  FileFilter(std::string filter, Format format);
+  std::string filter;  ///< filter string
+  Format format;       ///< IO format
+  bool operator==(const FileFilter& other) const;
+};
 
 /**
  * @brief Maps a file extension to a format value
@@ -45,6 +66,14 @@ enum class G2O_CORE_API Format { kG2O = 0, kBinary = 1, kJson = 2, kXML = 3 };
 G2O_CORE_API std::optional<Format> formatForFileExtension(
     std::string_view extension);
 
+/**
+ * @brief Get the filters for file open dialogs.
+ *
+ * @param open true, if opening files, false for save
+ * @return std::vector<std::string> Filters
+ */
+G2O_CORE_API std::vector<FileFilter> getFileFilter(bool open);
+
 }  // namespace g2o::io
 
 #endif
diff --git a/unit_test/general/graph_io.cpp b/unit_test/general/graph_io.cpp
index 6917dd742..d68fb67d3 100644
--- a/unit_test/general/graph_io.cpp
+++ b/unit_test/general/graph_io.cpp
@@ -316,3 +316,21 @@ const auto kFileformatsToTest = Values(
 INSTANTIATE_TEST_SUITE_P(AbstractGraph, AbstractGraphIO, kFileformatsToTest);
 INSTANTIATE_TEST_SUITE_P(OptimizableGraphGraph, OptimizableGraphIO,
                          kFileformatsToTest);
+
+TEST(OptimizableGraphIO, FileFilter) {
+  EXPECT_THAT(g2o::io::getFileFilter(false), Not(IsEmpty()));
+  EXPECT_THAT(g2o::io::getFileFilter(true), Not(IsEmpty()));
+  EXPECT_THAT(g2o::io::getFileFilter(false),
+              IsSubsetOf(g2o::io::getFileFilter(true)));
+}
+
+TEST(OptimizableGraphIO, FormatToString) {
+  static constexpr g2o::io::Format kAllFormats[] = {
+      g2o::io::Format::kUndefined, g2o::io::Format::kG2O,
+      g2o::io::Format::kBinary, g2o::io::Format::kJson, g2o::io::Format::kXML};
+  for (const auto& f : kAllFormats)
+    EXPECT_THAT(g2o::io::to_string(f), Not(IsEmpty()));
+
+  EXPECT_THAT(g2o::io::to_string(static_cast<g2o::io::Format>(1 << 31)),
+              IsEmpty());
+}