diff --git a/README.md b/README.md
index 58b3f86..eb34cd0 100644
--- a/README.md
+++ b/README.md
@@ -477,6 +477,11 @@ std::pair<iterator, bool> insert(const value_type& value);
 iterator insert(const_iterator hint, value_type&& value);
 iterator insert(const_iterator hint, const value_type& value);
 
+template < typename TT >
+std::pair<iterator, bool> insert_or_assign(key_type&& key, TT&& value);
+template < typename TT >
+std::pair<iterator, bool> insert_or_assign(const key_type& key, TT&& value);
+
 template < typename InputIter >
 void insert(InputIter first, InputIter last);
 template < typename InputIter >
@@ -490,6 +495,11 @@ std::pair<iterator, bool> emplace(Args&&... args);
 template < typename... Args >
 iterator emplace_hint(const_iterator hint, Args&&... args);
 
+template < typename... Args >
+std::pair<iterator, bool> try_emplace(key_type&& key, Args&&... args);
+template < typename... Args >
+std::pair<iterator, bool> try_emplace(const key_type& key, Args&&... args);
+
 void clear();
 iterator erase(const_iterator iter);
 iterator erase(const_iterator first, const_iterator last);
diff --git a/headers/flat.hpp/flat_map.hpp b/headers/flat.hpp/flat_map.hpp
index 25eb9b3..e32ae44 100644
--- a/headers/flat.hpp/flat_map.hpp
+++ b/headers/flat.hpp/flat_map.hpp
@@ -399,6 +399,28 @@ namespace flat_hpp
                 : insert(value).first;
         }
 
+        template < typename TT >
+        std::pair<iterator, bool> insert_or_assign(key_type&& key, TT&& value) {
+            iterator iter = lower_bound(key);
+            if ( iter == end() || this->operator()(key, *iter) ) {
+                iter = emplace_hint(iter, std::move(key), std::forward<TT>(value));
+                return {iter, true};
+            }
+            (*iter).second = std::forward<TT>(value);
+            return {iter, false};
+        }
+
+        template < typename TT >
+        std::pair<iterator, bool> insert_or_assign(const key_type& key, TT&& value) {
+            iterator iter = lower_bound(key);
+            if ( iter == end() || this->operator()(key, *iter) ) {
+                iter = emplace_hint(iter, key, std::forward<TT>(value));
+                return {iter, true};
+            }
+            (*iter).second = std::forward<TT>(value);
+            return {iter, false};
+        }
+
         template < typename InputIter >
         void insert(InputIter first, InputIter last) {
             insert_range_(first, last);
@@ -427,6 +449,26 @@ namespace flat_hpp
             return insert(hint, value_type(std::forward<Args>(args)...));
         }
 
+        template < typename... Args >
+        std::pair<iterator, bool> try_emplace(key_type&& key, Args&&... args) {
+            iterator iter = lower_bound(key);
+            if ( iter == end() || this->operator()(key, *iter) ) {
+                iter = emplace_hint(iter, std::move(key), std::forward<Args>(args)...);
+                return {iter, true};
+            }
+            return {iter, false};
+        }
+
+        template < typename... Args >
+        std::pair<iterator, bool> try_emplace(const key_type& key, Args&&... args) {
+            iterator iter = lower_bound(key);
+            if ( iter == end() || this->operator()(key, *iter) ) {
+                iter = emplace_hint(iter, key, std::forward<Args>(args)...);
+                return {iter, true};
+            }
+            return {iter, false};
+        }
+
         void clear()
         noexcept(noexcept(std::declval<container_type&>().clear())) {
             data_.clear();
@@ -508,6 +550,18 @@ namespace flat_hpp
                 : end();
         }
 
+        bool contains(const key_type& key) const {
+            return find(key) != end();
+        }
+
+        template < typename K >
+        std::enable_if_t<
+            detail::is_transparent_v<Compare, K>,
+            bool>
+        contains(const K& key) const {
+            return find(key) != end();
+        }
+
         std::pair<iterator, iterator> equal_range(const key_type& key) {
             const base_type& comp = *this;
             return std::equal_range(begin(), end(), key, comp);
diff --git a/headers/flat.hpp/flat_multimap.hpp b/headers/flat.hpp/flat_multimap.hpp
index 580435d..a0adff7 100644
--- a/headers/flat.hpp/flat_multimap.hpp
+++ b/headers/flat.hpp/flat_multimap.hpp
@@ -458,6 +458,18 @@ namespace flat_hpp
                 : end();
         }
 
+        bool contains(const key_type& key) const {
+            return find(key) != end();
+        }
+
+        template < typename K >
+        std::enable_if_t<
+            detail::is_transparent_v<Compare, K>,
+            bool>
+        contains(const K& key) const {
+            return find(key) != end();
+        }
+
         std::pair<iterator, iterator> equal_range(const key_type& key) {
             const base_type& comp = *this;
             return std::equal_range(begin(), end(), key, comp);
diff --git a/headers/flat.hpp/flat_multiset.hpp b/headers/flat.hpp/flat_multiset.hpp
index ae1fcb1..54e46e1 100644
--- a/headers/flat.hpp/flat_multiset.hpp
+++ b/headers/flat.hpp/flat_multiset.hpp
@@ -386,6 +386,18 @@ namespace flat_hpp
                 : end();
         }
 
+        bool contains(const key_type& key) const {
+            return find(key) != end();
+        }
+
+        template < typename K >
+        std::enable_if_t<
+            detail::is_transparent_v<Compare, K>,
+            bool>
+        contains(const K& key) const {
+            return find(key) != end();
+        }
+
         std::pair<iterator, iterator> equal_range(const key_type& key) {
             return std::equal_range(begin(), end(), key, key_comp());
         }
diff --git a/headers/flat.hpp/flat_set.hpp b/headers/flat.hpp/flat_set.hpp
index 18ca0aa..23244f1 100644
--- a/headers/flat.hpp/flat_set.hpp
+++ b/headers/flat.hpp/flat_set.hpp
@@ -436,6 +436,18 @@ namespace flat_hpp
                 : end();
         }
 
+        bool contains(const key_type& key) const {
+            return find(key) != end();
+        }
+
+        template < typename K >
+        std::enable_if_t<
+            detail::is_transparent_v<Compare, K>,
+            bool>
+        contains(const K& key) const {
+            return find(key) != end();
+        }
+
         std::pair<iterator, iterator> equal_range(const key_type& key) {
             return std::equal_range(begin(), end(), key, key_comp());
         }
diff --git a/untests/flat_map_tests.cpp b/untests/flat_map_tests.cpp
index 487daa0..5f0c406 100644
--- a/untests/flat_map_tests.cpp
+++ b/untests/flat_map_tests.cpp
@@ -369,6 +369,34 @@ TEST_CASE("flat_map") {
             s1.insert(sorted_range, {{1,3},{2,2},{2,2},{3,1}});
             REQUIRE(s1 == map_t{{1,3},{2,2},{3,1}});
         }
+
+        {
+            map_t s0;
+            auto i0 = s0.insert_or_assign(1, 4);
+            REQUIRE(i0 == std::make_pair(s0.begin(), true));
+            REQUIRE(s0 == map_t{{1,4}});
+            auto i1 = s0.insert_or_assign(1, 8);
+            REQUIRE(i1 == std::make_pair(s0.begin(), false));
+            REQUIRE(s0 == map_t{{1,8}});
+
+            const obj_t k0{2};
+            auto i2 = s0.insert_or_assign(k0, 6);
+            REQUIRE(i2 == std::make_pair(s0.begin() + 1, true));
+            REQUIRE(s0 == map_t{{1,8}, {2,6}});
+            auto i3 = s0.insert_or_assign(k0, 2);
+            REQUIRE(i3 == std::make_pair(s0.begin() + 1, false));
+            REQUIRE(s0 == map_t{{1,8}, {2,2}});
+        }
+
+        {
+            map_t s0;
+            auto i0 = s0.try_emplace(1, 4);
+            REQUIRE(i0 == std::make_pair(s0.begin(), true));
+            REQUIRE(s0 == map_t{{1,4}});
+            auto i1 = s0.try_emplace(1, 8);
+            REQUIRE(i1 == std::make_pair(s0.begin(), false));
+            REQUIRE(s0 == map_t{{1,4}});
+        }
     }
     SECTION("erasers") {
         using map_t = flat_map<int, unsigned>;
@@ -421,6 +449,9 @@ TEST_CASE("flat_map") {
             REQUIRE(my_as_const(s0).find(3) == s0.cbegin() + 2);
             REQUIRE(s0.find(6) == s0.end());
             REQUIRE(my_as_const(s0).find(0) == s0.cend());
+            REQUIRE(my_as_const(s0).contains(1));
+            REQUIRE(my_as_const(s0).contains(3));
+            REQUIRE_FALSE(my_as_const(s0).contains(0));
         }
         {
             map_t s0{{1,2},{2,3},{3,4},{4,5},{5,6}};
@@ -445,6 +476,9 @@ TEST_CASE("flat_map") {
         REQUIRE(s0.find(std::string_view("42")) == s0.end());
         REQUIRE(my_as_const(s0).find(std::string_view("42")) == s0.cend());
 
+        REQUIRE(my_as_const(s0).contains(std::string_view("hello")));
+        REQUIRE_FALSE(my_as_const(s0).contains(std::string_view("42")));
+
         REQUIRE(my_as_const(s0).count(std::string_view("hello")) == 1);
         REQUIRE(my_as_const(s0).count(std::string_view("hello_42")) == 0);
 
diff --git a/untests/flat_multimap_tests.cpp b/untests/flat_multimap_tests.cpp
index 9a3f90d..4c1559e 100644
--- a/untests/flat_multimap_tests.cpp
+++ b/untests/flat_multimap_tests.cpp
@@ -423,6 +423,9 @@ TEST_CASE("flat_multimap") {
             REQUIRE(my_as_const(s0).find(3) == s0.cbegin() + 2);
             REQUIRE(s0.find(6) == s0.end());
             REQUIRE(my_as_const(s0).find(0) == s0.cend());
+            REQUIRE(my_as_const(s0).contains(1));
+            REQUIRE(my_as_const(s0).contains(3));
+            REQUIRE_FALSE(my_as_const(s0).contains(0));
         }
         {
             map_t s0{{1,2},{2,3},{2,1},{3,4},{4,5},{5,6}};
@@ -447,6 +450,9 @@ TEST_CASE("flat_multimap") {
         REQUIRE(s0.find(std::string_view("42")) == s0.end());
         REQUIRE(my_as_const(s0).find(std::string_view("42")) == s0.cend());
 
+        REQUIRE(my_as_const(s0).contains(std::string_view("hello")));
+        REQUIRE_FALSE(my_as_const(s0).contains(std::string_view("42")));
+
         REQUIRE(my_as_const(s0).count(std::string_view("hello")) == 1);
         REQUIRE(my_as_const(s0).count(std::string_view("hello_42")) == 0);
 
diff --git a/untests/flat_multiset_tests.cpp b/untests/flat_multiset_tests.cpp
index aba9eea..985b1a8 100644
--- a/untests/flat_multiset_tests.cpp
+++ b/untests/flat_multiset_tests.cpp
@@ -399,6 +399,9 @@ TEST_CASE("flat_multiset") {
             REQUIRE(my_as_const(s0).find(3) == s0.cbegin() + 2);
             REQUIRE(s0.find(6) == s0.end());
             REQUIRE(my_as_const(s0).find(0) == s0.cend());
+            REQUIRE(my_as_const(s0).contains(1));
+            REQUIRE(my_as_const(s0).contains(3));
+            REQUIRE_FALSE(my_as_const(s0).contains(0));
         }
         {
             set_t s0{1,2,3,3,4,5};
@@ -423,6 +426,9 @@ TEST_CASE("flat_multiset") {
         REQUIRE(s0.find(std::string_view("42")) == s0.end());
         REQUIRE(my_as_const(s0).find(std::string_view("42")) == s0.cend());
 
+        REQUIRE(my_as_const(s0).contains(std::string_view("hello")));
+        REQUIRE_FALSE(my_as_const(s0).contains(std::string_view("42")));
+
         REQUIRE(my_as_const(s0).count(std::string_view("hello")) == 1);
         REQUIRE(my_as_const(s0).count(std::string_view("hello_42")) == 0);
 
diff --git a/untests/flat_set_tests.cpp b/untests/flat_set_tests.cpp
index ebbb99d..27866c9 100644
--- a/untests/flat_set_tests.cpp
+++ b/untests/flat_set_tests.cpp
@@ -397,6 +397,9 @@ TEST_CASE("flat_set") {
             REQUIRE(my_as_const(s0).find(3) == s0.cbegin() + 2);
             REQUIRE(s0.find(6) == s0.end());
             REQUIRE(my_as_const(s0).find(0) == s0.cend());
+            REQUIRE(my_as_const(s0).contains(1));
+            REQUIRE(my_as_const(s0).contains(3));
+            REQUIRE_FALSE(my_as_const(s0).contains(0));
         }
         {
             set_t s0{1,2,3,4,5};
@@ -421,6 +424,9 @@ TEST_CASE("flat_set") {
         REQUIRE(s0.find(std::string_view("42")) == s0.end());
         REQUIRE(my_as_const(s0).find(std::string_view("42")) == s0.cend());
 
+        REQUIRE(my_as_const(s0).contains(std::string_view("hello")));
+        REQUIRE_FALSE(my_as_const(s0).contains(std::string_view("42")));
+
         REQUIRE(my_as_const(s0).count(std::string_view("hello")) == 1);
         REQUIRE(my_as_const(s0).count(std::string_view("hello_42")) == 0);