diff --git a/include/mbedtls/ssl.h b/include/mbedtls/ssl.h
index 3165cd5..edc1a98 100644
--- a/include/mbedtls/ssl.h
+++ b/include/mbedtls/ssl.h
@@ -1524,9 +1524,17 @@
 #endif /* MBEDTLS_SSL_HANDSHAKE_WITH_PSK_ENABLED */
 
 #if defined(MBEDTLS_SSL_EARLY_DATA)
+#if defined(MBEDTLS_SSL_CLI_C)
     int MBEDTLS_PRIVATE(early_data_enabled);     /*!< Early data enablement:
                                                   *   - MBEDTLS_SSL_EARLY_DATA_DISABLED,
                                                   *   - MBEDTLS_SSL_EARLY_DATA_ENABLED */
+#endif /* MBEDTLS_SSL_CLI_C */
+
+#if defined(MBEDTLS_SSL_SRV_C)
+    /* The maximium amount of 0-RTT data. RFC 8446 section 4.6.1 */
+    uint32_t MBEDTLS_PRIVATE(max_early_data_size);
+#endif /* MBEDTLS_SSL_SRV_C */
+
 #endif /* MBEDTLS_SSL_EARLY_DATA */
 
 #if defined(MBEDTLS_SSL_ALPN)
@@ -1943,6 +1951,7 @@
 void mbedtls_ssl_conf_authmode( mbedtls_ssl_config *conf, int authmode );
 
 #if defined(MBEDTLS_SSL_PROTO_TLS1_3) && defined(MBEDTLS_SSL_EARLY_DATA)
+#if defined(MBEDTLS_SSL_CLI_C)
 /**
 * \brief    Set the early data mode
 *           Default: disabled on server and client
@@ -1964,6 +1973,27 @@
 */
 void mbedtls_ssl_tls13_conf_early_data( mbedtls_ssl_config *conf,
                                         int early_data_enabled );
+#endif /* MBEDTLS_SSL_CLI_C */
+
+#if defined(MBEDTLS_SSL_SRV_C)
+/**
+ * \brief Set the max_early_data_size parameter.
+ *
+ * \param[in] conf                  The SSL configuration to use.
+ * \param[in] max_early_data_size   The maximum amount of 0-RTT data.
+ *                                  - 0 Disable 0-RTT feature.
+ *
+ * \note    max_early_data_size MUST be smaller than
+ *          MBEDTLS_SSL_MAX_EARLY_DATA_SIZE. Otherwise,
+ *          MBEDTLS_SSL_MAX_EARLY_DATA_SIZE will be used.
+ *
+ * \warning This interface is experimental and may change without notice.
+ *
+ */
+void mbedtls_ssl_tls13_conf_max_early_data_size(
+         mbedtls_ssl_config *conf, uint32_t max_early_data_size );
+#endif /* MBEDTLS_SSL_SRV_C */
+
 #endif /* MBEDTLS_SSL_PROTO_TLS1_3 && MBEDTLS_SSL_EARLY_DATA */
 
 #if defined(MBEDTLS_X509_CRT_PARSE_C)
diff --git a/library/ssl_tls.c b/library/ssl_tls.c
index 83f2b3c..14ffef2 100644
--- a/library/ssl_tls.c
+++ b/library/ssl_tls.c
@@ -1699,11 +1699,24 @@
 }
 
 #if defined(MBEDTLS_SSL_EARLY_DATA)
+#if defined(MBEDTLS_SSL_CLI_C)
 void mbedtls_ssl_tls13_conf_early_data( mbedtls_ssl_config *conf,
                                         int early_data_enabled )
 {
     conf->early_data_enabled = early_data_enabled;
 }
+#endif /* MBEDTLS_SSL_CLI_C */
+
+#if defined(MBEDTLS_SSL_SRV_C)
+void mbedtls_ssl_tls13_conf_max_early_data_size(
+         mbedtls_ssl_config *conf, uint32_t max_early_data_size )
+{
+    conf->max_early_data_size =
+        max_early_data_size < MBEDTLS_SSL_MAX_EARLY_DATA_SIZE ?
+                        max_early_data_size : MBEDTLS_SSL_MAX_EARLY_DATA_SIZE;
+}
+#endif /* MBEDTLS_SSL_SRV_C */
+
 #endif /* MBEDTLS_SSL_EARLY_DATA */
 #endif /* MBEDTLS_SSL_PROTO_TLS1_3 */