diff --git a/libs/client-sdk/include/launchdarkly/client_side/bindings/c/config/builder.h b/libs/client-sdk/include/launchdarkly/client_side/bindings/c/config/builder.h
index 81c5cb64c..cc8a7c9ba 100644
--- a/libs/client-sdk/include/launchdarkly/client_side/bindings/c/config/builder.h
+++ b/libs/client-sdk/include/launchdarkly/client_side/bindings/c/config/builder.h
@@ -421,6 +421,28 @@ LDClientConfigBuilder_HttpProperties_Header(LDClientConfigBuilder b,
                                             char const* key,
                                             char const* value);
 
+/**
+ * Specifies an HTTP proxy which the client should use to communicate
+ * with LaunchDarkly.
+ *
+ * SDK <-- HTTP, plaintext --> Proxy <-- HTTPS --> LaunchDarkly
+ *
+ * This setting affects streaming mode, polling mode, and event delivery.
+ * The argument should be of the form: 'http://proxy.example.com:8080'.
+ *
+ * The scheme must be 'http' and the port is optional (80 if not
+ * specified.)
+ *
+ * The SDK respects the 'http_proxy' environment variable as an alternative
+ * to this method. If both are set, this method takes precedence.
+ *
+ * @param b Client config builder. Must not be NULL.
+ * @param http_proxy HTTP proxy URL. Must not be NULL.
+ */
+LD_EXPORT(void)
+LDClientConfigBuilder_HttpProperties_HttpProxy(LDClientConfigBuilder b,
+                                               char const* http_proxy);
+
 /**
  * Sets the TLS options builder. The builder is automatically freed.
  *
diff --git a/libs/client-sdk/src/bindings/c/builder.cpp b/libs/client-sdk/src/bindings/c/builder.cpp
index 7994207e4..6de3bb647 100644
--- a/libs/client-sdk/src/bindings/c/builder.cpp
+++ b/libs/client-sdk/src/bindings/c/builder.cpp
@@ -311,6 +311,15 @@ LDClientConfigBuilder_HttpProperties_Header(LDClientConfigBuilder b,
     TO_BUILDER(b)->HttpProperties().Header(key, value);
 }
 
+LD_EXPORT(void)
+LDClientConfigBuilder_HttpProperties_HttpProxy(LDClientConfigBuilder b,
+                                               char const* http_proxy) {
+    LD_ASSERT_NOT_NULL(b);
+    LD_ASSERT_NOT_NULL(http_proxy);
+
+    TO_BUILDER(b)->HttpProperties().HttpProxy(http_proxy);
+}
+
 LD_EXPORT(void)
 LDClientConfigBuilder_HttpProperties_Tls(
     LDClientConfigBuilder b,
diff --git a/libs/common/include/launchdarkly/config/shared/builders/http_properties_builder.hpp b/libs/common/include/launchdarkly/config/shared/builders/http_properties_builder.hpp
index 2f2de60ec..ffe1a5f3e 100644
--- a/libs/common/include/launchdarkly/config/shared/builders/http_properties_builder.hpp
+++ b/libs/common/include/launchdarkly/config/shared/builders/http_properties_builder.hpp
@@ -179,16 +179,24 @@ class HttpPropertiesBuilder {
     HttpPropertiesBuilder& Tls(TlsBuilder<SDK> builder);
 
     /**
-     * Sets an HTTP proxy URL.
-     * @param http_proxy The proxy, for example 'http://proxy.example.com:8080'.
-     * @return A reference to this builder.
+     * Specifies an HTTP proxy which the client should use to communicate
+     * with LaunchDarkly.
+     *
+     * SDK <-- HTTP, plaintext --> Proxy <-- HTTPS --> LaunchDarkly
+     *
+     * This setting affects streaming mode, polling mode, and event delivery.
+     * The argument should be of the form: 'http://proxy.example.com:8080'.
+     *
+     * The scheme must be 'http' and the port is optional (80 if not
+     * specified.)
+     *
+     * The SDK respects the 'http_proxy' environment variable as an alternative
+     * to this method. If both are set, this method takes precedence.
+     *
+     * @param http_proxy HTTP proxy URL.
      */
     HttpPropertiesBuilder& HttpProxy(std::string http_proxy);
 
-    /**
-     * Build a set of HttpProperties.
-     * @return The built properties.
-     */
     [[nodiscard]] built::HttpProperties Build() const;
 
    private:
diff --git a/libs/common/src/config/http_properties_builder.cpp b/libs/common/src/config/http_properties_builder.cpp
index 8fa08b8c4..3ddfb6651 100644
--- a/libs/common/src/config/http_properties_builder.cpp
+++ b/libs/common/src/config/http_properties_builder.cpp
@@ -153,7 +153,7 @@ built::HttpProperties HttpPropertiesBuilder<SDK>::Build() const {
             response_timeout_,
             std::move(headers),
             tls_.Build(),
-            http_proxy_ ? *http_proxy_ : HttpProxyFromEnv()};
+            http_proxy_.has_value() ? http_proxy_ : HttpProxyFromEnv()};
 }
 
 template class TlsBuilder<config::shared::ClientSDK>;
diff --git a/libs/server-sdk/src/data_systems/background_sync/sources/streaming/streaming_data_source.cpp b/libs/server-sdk/src/data_systems/background_sync/sources/streaming/streaming_data_source.cpp
index f831b34d9..778eef153 100644
--- a/libs/server-sdk/src/data_systems/background_sync/sources/streaming/streaming_data_source.cpp
+++ b/libs/server-sdk/src/data_systems/background_sync/sources/streaming/streaming_data_source.cpp
@@ -119,10 +119,6 @@ void StreamingDataSource::StartAsync(
         client_builder.custom_ca_file(*ca_file);
     }
 
-    if (http_config_.HttpProxy()) {
-        client_builder.http_proxy(*http_config_.HttpProxy());
-    }
-
     auto weak_self = weak_from_this();
 
     client_builder.receiver([weak_self](launchdarkly::sse::Event const& event) {
diff --git a/libs/server-sent-events/src/client.cpp b/libs/server-sent-events/src/client.cpp
index 91353f623..cd39354b0 100644
--- a/libs/server-sent-events/src/client.cpp
+++ b/libs/server-sent-events/src/client.cpp
@@ -660,13 +660,6 @@ std::shared_ptr<Client> Builder::build() {
             return nullptr;
         }
 
-        // Although a proxy might talk HTTP on port 443, that would be
-        // very weird and is likely a misconfiguration.
-        if (http_proxy_components->has_port() &&
-            http_proxy_components->port() == "443") {
-            return nullptr;
-        }
-
         tcp_host = http_proxy_components->host();
 
         // If they didn't specify a port, then the uri is of the form