diff --git a/include/boost/url/impl/params_encoded_base.hpp b/include/boost/url/impl/params_encoded_base.hpp
index 5ff1e0dd1..c220bfe7d 100644
--- a/include/boost/url/impl/params_encoded_base.hpp
+++ b/include/boost/url/impl/params_encoded_base.hpp
@@ -130,6 +130,27 @@ contains(
         begin().it_, key, ic) != end();
 }
 
+inline
+pct_string_view
+params_encoded_base::
+get_or(
+    pct_string_view key,
+    pct_string_view value,
+    ignore_case_param ic) const noexcept
+{
+    auto it = find_impl(
+        begin().it_, key, ic);
+    detail::params_iter_impl end_(ref_, 0);
+    if(it.equal(end_))
+        return value;
+
+    param_pct_view const p = it.dereference();
+    if(! p.has_value)
+        return pct_string_view();
+
+    return p.value;
+}
+
 inline
 auto
 params_encoded_base::
diff --git a/include/boost/url/params_base.hpp b/include/boost/url/params_base.hpp
index e972d4273..6553da5d5 100644
--- a/include/boost/url/params_base.hpp
+++ b/include/boost/url/params_base.hpp
@@ -29,11 +29,12 @@ namespace urls {
 #   pragma warning(disable: 4251)
 #endif
 
-/** Common functionality for query parameter containers
+/** Decoded query parameter helper base
 
-    The library uses this base class
-    to provide common member functions for
-    containers of query parameters.
+    This base centralizes the read-only,
+    percent-decoded query parameter algorithms
+    (iteration, lookup, counting) that are
+    shared by @ref params_view and @ref params_ref.
 
     This class should not be instantiated
     directly; Instead, use one of the
@@ -319,6 +320,45 @@ class BOOST_URL_DECL params_base
         core::string_view key,
         ignore_case_param ic = {}) const noexcept;
 
+    /** Return the value for a key or a fallback
+
+        This convenience function searches for the
+        first parameter matching `key` and returns
+        its decoded value. If no parameter with the
+        specified key exists, the provided fallback
+        `value` is returned instead. When the key is
+        found but the parameter has no value, an
+        empty string is returned.
+
+        @par Example
+        @code
+        url_view u( "/path?first=John&last=Doe" );
+        assert( u.params().get_or( "first", "n/a" ) == "John" );
+        assert( u.params().get_or( "missing", "n/a" ) == "n/a" );
+        @endcode
+
+        @par Complexity
+        Linear in `this->buffer().size()`.
+
+        @par Exception Safety
+        Calls to allocate may throw.
+
+        @param key The key to match.
+        @param value The fallback string returned
+        when no matching key exists. If this
+        parameter is omitted, an empty string is
+        used.
+        @param ic Optional case-insensitive compare
+        indicator.
+
+        @return The decoded value or the fallback.
+    */
+    std::string
+    get_or(
+        core::string_view key,
+        core::string_view value = {},
+        ignore_case_param ic = {}) const;
+
     /** Find a matching key
 
         This function examines the parameters
diff --git a/include/boost/url/params_encoded_base.hpp b/include/boost/url/params_encoded_base.hpp
index 3e26cb4ec..98cd67a17 100644
--- a/include/boost/url/params_encoded_base.hpp
+++ b/include/boost/url/params_encoded_base.hpp
@@ -21,13 +21,15 @@
 namespace boost {
 namespace urls {
 
-/** Common functionality for containers
+/** Percent-encoded query helper base
 
-    This base class is used by the library
-    to provide common member functions for
-    containers. This cannot be instantiated
-    directly; Instead, use one of the
-    containers or functions:
+    This base implements the shared
+    percent-encoded query parameter view
+    functionality used by @ref params_encoded_view
+    and @ref params_encoded_ref. It cannot be
+    instantiated directly; instead, use one of
+    those containers or the corresponding ref
+    adaptors.
 
     @par Containers
     @li @ref params_ref
@@ -319,6 +321,46 @@ class BOOST_URL_DECL params_encoded_base
         pct_string_view key,
         ignore_case_param ic = {}) const noexcept;
 
+    /** Return the value for a key or a fallback
+
+        This convenience function searches for the
+        first parameter matching `key` and returns
+        its percent-encoded value. If no parameter
+        with the specified key exists, the provided
+        fallback `value` is returned instead. When
+        the key is found but the corresponding
+        parameter has no value, an empty string is
+        returned.
+
+        @par Example
+        @code
+        url_view u( "/path?first=John&last=Doe" );
+        assert( u.encoded_params().get_or(
+            "missing", "n%2Fa" ) == "n%2Fa" );
+        @endcode
+
+        @par Complexity
+        Linear in `this->buffer().size()`.
+
+        @par Exception Safety
+        Throws nothing.
+
+        @param key The key to match.
+        @param value The fallback string returned
+        when no matching key exists. If this
+        parameter is omitted, an empty string is
+        used.
+        @param ic Optional case-insensitive compare
+        indicator.
+
+        @return The encoded value or the fallback.
+    */
+    pct_string_view
+    get_or(
+        pct_string_view key,
+        pct_string_view value = {},
+        ignore_case_param ic = {}) const noexcept;
+
     /** Find a matching key
 
         This function examines the parameters
diff --git a/include/boost/url/params_encoded_ref.hpp b/include/boost/url/params_encoded_ref.hpp
index 67cb6a403..4ac8d230a 100644
--- a/include/boost/url/params_encoded_ref.hpp
+++ b/include/boost/url/params_encoded_ref.hpp
@@ -24,21 +24,14 @@ class url_base;
 class params_encoded_view;
 #endif
 
-/** A view representing query parameters in a URL
+/** Mutable encoded query parameter proxy
 
-    Objects of this type are used to interpret
-    the query parameters as a bidirectional view
-    of key value pairs.
-
-    The view does not retain ownership of the
-    elements and instead references the original
-    url. The caller is responsible for ensuring
-    that the lifetime of the referenced url
-    extends until it is no longer referenced.
-
-    The view is modifiable; calling non-const
-    members causes changes to the referenced
-    url.
+    This container exposes the percent-encoded
+    query parameters of a @ref url_base as a
+    bidirectional range while allowing mutation
+    of the underlying URL. It references the
+    URL’s buffer directly, so the url must stay
+    alive for the lifetime of the proxy.
 
     @par Example
     @code
@@ -69,6 +62,17 @@ class params_encoded_view;
     @li @ref replace, @ref set : Modified
         params and all params
         after (including `end()`).
+
+    @par Reads vs. writes
+    Even though this type can be used to mutate
+    the referenced URL, this is still a proxy
+    and every observer function inherited
+    from @ref params_encoded_base (for example
+    @ref contains, @ref find, and @ref get_or)
+    behaves like the corresponding function on
+    @ref params_encoded_view: it inspects the
+    current encoded query and does not perform
+    any modifications.
 */
 class BOOST_URL_DECL params_encoded_ref
     : public params_encoded_base
diff --git a/include/boost/url/params_encoded_view.hpp b/include/boost/url/params_encoded_view.hpp
index 624dba84f..ec553e862 100644
--- a/include/boost/url/params_encoded_view.hpp
+++ b/include/boost/url/params_encoded_view.hpp
@@ -26,17 +26,13 @@ namespace implementation_defined {
     struct query_rule_t;
 }
 
-/** A view representing query parameters in a URL
+/** Non-owning encoded query parameter view
 
-    Objects of this type are used to interpret
-    the query parameters as a bidirectional view
-    of key/value pairs.
-
-    The view does not retain ownership of the
-    elements and instead references the original
-    character buffer. The caller is responsible
-    for ensuring that the lifetime of the buffer
-    extends until it is no longer referenced.
+    This read-only range exposes the raw
+    percent-encoded key/value pairs stored in a
+    query string. It does not copy the underlying
+    buffer; callers must ensure the referenced
+    character storage outlives the view.
 
     @par Example
     @code
@@ -45,11 +41,9 @@ namespace implementation_defined {
     params_encoded_view p = u.encoded_params();
     @endcode
 
-    Strings produced when elements are returned
-    have type @ref param_pct_view and represent
-    encoded strings. Strings passed to member
-    functions may contain percent escapes, and
-    throw exceptions on invalid inputs.
+    Iteration yields @ref param_pct_view values,
+    so encoded strings and escape validation are
+    preserved for callers that want exact bytes.
 
     @par Iterator Invalidation
     Changes to the underlying character buffer
diff --git a/include/boost/url/params_ref.hpp b/include/boost/url/params_ref.hpp
index de2e53361..5ce4d5bc1 100644
--- a/include/boost/url/params_ref.hpp
+++ b/include/boost/url/params_ref.hpp
@@ -25,19 +25,15 @@ class url_base;
 class params_view;
 #endif
 
-/** A view representing query parameters in a URL
-
-    Objects of this type are used to interpret
-    the query parameters as a bidirectional view
-    of key/value pairs.
-    The view does not retain ownership of the
-    elements and instead references the original
-    url. The caller is responsible for ensuring
-    that the lifetime of the referenced url
-    extends until it is no longer referenced.
-    The view is modifiable; calling non-const
-    members causes changes to the referenced
-    url.
+/** Mutable decoded query parameter proxy
+
+    This container presents the decoded query
+    parameters of a @ref url_base as a bidirectional
+    range whose modifying operations update the
+    underlying URL in-place. It references (but
+    does not own) the character buffer, so the
+    referenced URL must stay alive while the proxy
+    is used.
 
     <br>
 
@@ -76,6 +72,16 @@ class params_view;
     @li @ref replace, @ref set : Modified
         elements and all elements
         after (including `end()`).
+
+    @par Reads vs. writes
+    Although this is a mutable proxy, all
+    observer helpers inherited from
+    @ref params_base (such as @ref contains,
+    @ref find, and @ref get_or) operate in the
+    same way as they do on @ref params_view:
+    they perform their lookup against the
+    current contents of the referenced URL
+    without modifying it.
 */
 class BOOST_URL_DECL params_ref
     : public params_base
diff --git a/include/boost/url/params_view.hpp b/include/boost/url/params_view.hpp
index fb3d2b782..4ff9f63b8 100644
--- a/include/boost/url/params_view.hpp
+++ b/include/boost/url/params_view.hpp
@@ -17,17 +17,14 @@
 namespace boost {
 namespace urls {
 
-/** A view representing query parameters in a URL
+/** Non-owning decoded query parameter view
 
-    Objects of this type are used to interpret
-    the query parameters as a bidirectional view
-    of key/value pairs.
-
-    The view does not retain ownership of the
-    elements and instead references the original
-    character buffer. The caller is responsible
-    for ensuring that the lifetime of the buffer
-    extends until it is no longer referenced.
+    This read-only range interprets the query
+    string of a URL as bidirectional key/value
+    pairs with percent-decoding applied on
+    access. It merely references the original
+    character buffer; callers must keep that
+    buffer alive while the view is used.
 
     @par Example
     @code
@@ -36,9 +33,8 @@ namespace urls {
     params_view p = u.params();
     @endcode
 
-    Percent escapes in strings returned when
-    dereferencing iterators are automatically
-    decoded.
+    Strings retrieved from the iterators are
+    automatically percent-decoded.
 
     @par Iterator Invalidation
     Changes to the underlying character buffer
diff --git a/include/boost/url/segments_base.hpp b/include/boost/url/segments_base.hpp
index 3c50ba6ae..779513536 100644
--- a/include/boost/url/segments_base.hpp
+++ b/include/boost/url/segments_base.hpp
@@ -20,13 +20,14 @@
 namespace boost {
 namespace urls {
 
-/** Common functionality for containers
-
-    This base class is used by the library
-    to provide common member functions for
-    containers. This cannot be instantiated
-    directly; Instead, use one of the
-    containers or functions:
+/** Decoded path segment helper base
+
+    Provides the shared decoded path-segment
+    algorithms (iteration, lookup, comparison)
+    used by @ref segments_view and
+    @ref segments_ref. This base cannot be
+    instantiated directly; instead, use one of
+    the concrete containers below.
 
     @par Containers
     @li @ref segments_ref
diff --git a/include/boost/url/segments_encoded_base.hpp b/include/boost/url/segments_encoded_base.hpp
index 7390c00cc..d181a121b 100644
--- a/include/boost/url/segments_encoded_base.hpp
+++ b/include/boost/url/segments_encoded_base.hpp
@@ -20,13 +20,13 @@
 namespace boost {
 namespace urls {
 
-/** Common functionality for containers
+/** Percent-encoded path segment helper base
 
-    This base class is used by the library
-    to provide common member functions for
-    containers. This cannot be instantiated
-    directly; Instead, use one of the
-    containers or functions:
+    Implements the shared encoded-segment
+    algorithms reused by @ref segments_encoded_view
+    and @ref segments_encoded_ref. It is not
+    intended to be instantiated directly; use
+    one of those concrete containers instead.
 
     @par Containers
     @li @ref segments_ref
diff --git a/include/boost/url/segments_encoded_ref.hpp b/include/boost/url/segments_encoded_ref.hpp
index 7e35fb6af..30abc4633 100644
--- a/include/boost/url/segments_encoded_ref.hpp
+++ b/include/boost/url/segments_encoded_ref.hpp
@@ -24,22 +24,13 @@ class url_base;
 class segments_encoded_view;
 #endif
 
-/** A view representing path segments in a URL
-
-    Objects of this type are used to interpret
-    the path as a bidirectional view of segments,
-    where each segment is a string which may
-    contain percent-escapes.
-
-    The view does not retain ownership of the
-    elements and instead references the original
-    character buffer. The caller is responsible
-    for ensuring that the lifetime of the buffer
-    extends until it is no longer referenced.
-
-    The view is modifiable; calling non-const
-    members causes changes to the referenced
-    url.
+/** Mutable encoded path segment proxy
+
+    Exposes the percent-encoded segments of a
+    @ref url_base as a bidirectional range that
+    can modify the underlying URL. The proxy uses
+    the URL’s storage directly, so the url must
+    outlive any references.
 
     @par Example
     @code
diff --git a/include/boost/url/segments_encoded_view.hpp b/include/boost/url/segments_encoded_view.hpp
index 847fc553c..db1ebed0a 100644
--- a/include/boost/url/segments_encoded_view.hpp
+++ b/include/boost/url/segments_encoded_view.hpp
@@ -22,17 +22,13 @@
 namespace boost {
 namespace urls {
 
-/** A view representing path segments in a URL
+/** Non-owning encoded path segment view
 
-    Objects of this type are used to interpret
-    the path as a bidirectional view of segment
-    strings.
-
-    The view does not retain ownership of the
-    elements and instead references the original
-    character buffer. The caller is responsible
-    for ensuring that the lifetime of the buffer
-    extends until it is no longer referenced.
+    Exposes the raw percent-encoded segments of
+    a URL path as a read-only bidirectional range.
+    The view references the original buffer, so
+    callers must keep that storage alive while
+    iterating.
 
     @par Example
     @code
@@ -43,11 +39,9 @@ namespace urls {
     assert( ps.buffer().data() == u.buffer().data() );
     @endcode
 
-    Strings produced when elements are returned
-    have type @ref param_pct_view and represent
-    encoded strings. Strings passed to member
-    functions may contain percent escapes, and
-    throw exceptions on invalid inputs.
+    Elements are returned as encoded strings,
+    preserving escape sequences for callers that
+    need the exact byte representation.
 
     @par Iterator Invalidation
     Changes to the underlying character buffer
diff --git a/include/boost/url/segments_ref.hpp b/include/boost/url/segments_ref.hpp
index 8c26f185c..d9dbb3312 100644
--- a/include/boost/url/segments_ref.hpp
+++ b/include/boost/url/segments_ref.hpp
@@ -24,22 +24,14 @@ class url_base;
 class segments_view;
 #endif
 
-/** A view representing path segments in a URL
-
-    Objects of this type are used to interpret
-    the path as a bidirectional view of segments,
-    where each segment is a string with percent
-    escapes automatically decoded.
-
-    The view does not retain ownership of the
-    elements and instead references the original
-    character buffer. The caller is responsible
-    for ensuring that the lifetime of the buffer
-    extends until it is no longer referenced.
-
-    The view is modifiable; calling non-const
-    members causes changes to the referenced
-    url.
+/** Mutable decoded path segment proxy
+
+    Presents the decoded path segments of a
+    @ref url_base as a bidirectional range whose
+    modifiers update the underlying URL. The proxy
+    references the URL’s storage directly, so the
+    owning URL must remain alive while the proxy
+    is used.
 
     @par Example
     @code
diff --git a/include/boost/url/segments_view.hpp b/include/boost/url/segments_view.hpp
index c8560dca7..77fb2a80d 100644
--- a/include/boost/url/segments_view.hpp
+++ b/include/boost/url/segments_view.hpp
@@ -18,17 +18,13 @@
 namespace boost {
 namespace urls {
 
-/** A view representing path segments in a URL
+/** Non-owning decoded path segment view
 
-    Objects of this type are used to interpret
-    the path as a bidirectional view of segment
-    strings.
-
-    The view does not retain ownership of the
-    elements and instead references the original
-    character buffer. The caller is responsible
-    for ensuring that the lifetime of the buffer
-    extends until it is no longer referenced.
+    Presents the path of a URL as a read-only
+    bidirectional range of percent-decoded
+    segments. The range references the original
+    buffer, so callers must keep that storage
+    alive for as long as the view is accessed.
 
     @par Example
     @code
@@ -39,9 +35,8 @@ namespace urls {
     assert( ps.buffer().data() == u.buffer().data() );
     @endcode
 
-    Percent escapes in strings returned when
-    dereferencing iterators are automatically
-    decoded.
+    Any percent-escapes are decoded on demand
+    when iterators are dereferenced.
 
     @par Iterator Invalidation
     Changes to the underlying character buffer
diff --git a/src/params_base.cpp b/src/params_base.cpp
index ca1532ea5..a27d58be0 100644
--- a/src/params_base.cpp
+++ b/src/params_base.cpp
@@ -14,6 +14,7 @@
 #include <boost/url/params_base.hpp>
 #include <boost/url/grammar/ci_string.hpp>
 #include <ostream>
+#include <string>
 
 namespace boost {
 namespace urls {
@@ -203,6 +204,27 @@ count(
     return n;
 }
 
+std::string
+params_base::
+get_or(
+    core::string_view key,
+    core::string_view value,
+    ignore_case_param ic) const
+{
+    auto it = find_impl(
+        begin().it_, key, ic);
+    detail::params_iter_impl end_(ref_, 0);
+    if(it.equal(end_))
+        return std::string(value);
+
+    param_pct_view const p = it.dereference();
+    if(! p.has_value)
+        return std::string();
+
+    auto opt = opt_;
+    return p.value.decode(opt);
+}
+
 //------------------------------------------------
 //
 // (implementation)
@@ -282,4 +304,3 @@ operator<<(
 
 } // urls
 } // boost
-
diff --git a/test/unit/params_base.cpp b/test/unit/params_base.cpp
index 82a0e2da6..97d320fa5 100644
--- a/test/unit/params_base.cpp
+++ b/test/unit/params_base.cpp
@@ -283,6 +283,32 @@ struct params_base_test
             BOOST_TEST(p.contains("F", ignore_case));
             BOOST_TEST(! p.contains("G", ignore_case));
         }
+
+        // get_or()
+        {
+            url_view u(
+                "?first=John&empty=&novalue&encoded=John%20Doe");
+            params_view p = u.params();
+
+            BOOST_TEST_EQ(p.get_or("first", "n/a"), "John");
+            BOOST_TEST_EQ(p.get_or("encoded", "n/a"), "John Doe");
+            BOOST_TEST_EQ(p.get_or("missing", "n/a"), "n/a");
+            BOOST_TEST_EQ(p.get_or("novalue", "fallback"), "");
+            BOOST_TEST_EQ(p.get_or("empty", "fallback"), "");
+            BOOST_TEST_EQ(
+                p.get_or("FIRST", "n/a", ignore_case), "John");
+        }
+
+        // javadoc
+        {
+            url_view u("/path?first=John&last=Doe");
+            BOOST_TEST_EQ(
+                u.params().get_or("first", "n/a"),
+                "John");
+            BOOST_TEST_EQ(
+                u.params().get_or("missing", "n/a"),
+                "n/a");
+        }
     }
 
     void
diff --git a/test/unit/params_encoded_base.cpp b/test/unit/params_encoded_base.cpp
index 6e354ac01..d1534d82a 100644
--- a/test/unit/params_encoded_base.cpp
+++ b/test/unit/params_encoded_base.cpp
@@ -283,6 +283,30 @@ struct params_encoded_base_test
             BOOST_TEST(p.contains("F", ignore_case));
             BOOST_TEST(! p.contains("G", ignore_case));
         }
+
+        // get_or()
+        {
+            url_view u(
+                "?first=John&empty=&novalue&encoded=John%20Doe");
+            params_encoded_view p = u.encoded_params();
+
+            BOOST_TEST_EQ(p.get_or("first", "n%2Fa"), "John");
+            BOOST_TEST_EQ(p.get_or("encoded", "n%2Fa"), "John%20Doe");
+            BOOST_TEST_EQ(p.get_or("missing", "n%2Fa"), "n%2Fa");
+            BOOST_TEST_EQ(p.get_or("novalue", "fallback"), "");
+            BOOST_TEST_EQ(p.get_or("empty", "fallback"), "");
+            BOOST_TEST_EQ(
+                p.get_or("FIRST", "n%2Fa", ignore_case), "John");
+        }
+
+        // javadoc
+        {
+            url_view u("/path?first=John&last=Doe");
+            BOOST_TEST_EQ(
+                u.encoded_params().get_or(
+                    "missing", "n%2Fa"),
+                "n%2Fa");
+        }
     }
 
     void