diff --git a/include/libwebsockets/lws-misc.h b/include/libwebsockets/lws-misc.h
index 1d36923b0..493218c10 100644
--- a/include/libwebsockets/lws-misc.h
+++ b/include/libwebsockets/lws-misc.h
@@ -723,6 +723,10 @@ lws_vbi_decode(const void *buf, uint64_t *value, size_t len);
 /* opaque internal struct */
 struct lws_spawn_piped;
 
+#if defined(WIN32)
+typedef struct _lws_siginfo_t *siginfo_t;
+#endif
+
 typedef void (*lsp_cb_t)(void *opaque, lws_usec_t *accounting, siginfo_t *si,
 			 int we_killed_him);
 
diff --git a/lib/misc/lws-struct-lejp.c b/lib/misc/lws-struct-lejp.c
index 477bd55e9..627a891fa 100644
--- a/lib/misc/lws-struct-lejp.c
+++ b/lib/misc/lws-struct-lejp.c
@@ -675,7 +675,7 @@ lws_struct_json_serialize(lws_struct_serialize_t *js, uint8_t *buf,
 			 * in "used".
 			 */
 
-			lws_json_purify((char *)buf, q, len, &used);
+			lws_json_purify((char *)buf, q, (int)len, &used);
 			m = strlen((const char *)buf);
 			buf += m;
 			len -= m;
diff --git a/lib/secure-streams/policy-common.c b/lib/secure-streams/policy-common.c
index 98102dfc3..24fe833b8 100644
--- a/lib/secure-streams/policy-common.c
+++ b/lib/secure-streams/policy-common.c
@@ -202,7 +202,8 @@ lws_ss_policy_set(struct lws_context *context, const char *name)
 		i.vhost_name = pol->trust_store->name;
 		lwsl_debug("%s: %s\n", __func__, i.vhost_name);
 		i.client_ssl_ca_mem = pol->trust_store->ssx509[0]->ca_der;
-		i.client_ssl_ca_mem_len = pol->trust_store->ssx509[0]->ca_der_len;
+		i.client_ssl_ca_mem_len = (unsigned int)
+				pol->trust_store->ssx509[0]->ca_der_len;
 		i.port = CONTEXT_PORT_NO_LISTEN;
 		lwsl_info("%s: %s trust store initial '%s'\n", __func__,
 			  i.vhost_name, pol->trust_store->ssx509[0]->vhost_name);
diff --git a/lib/secure-streams/policy-json.c b/lib/secure-streams/policy-json.c
index 49eb0e5ed..51c05f1a8 100644
--- a/lib/secure-streams/policy-json.c
+++ b/lib/secure-streams/policy-json.c
@@ -365,7 +365,7 @@ lws_ss_policy_parser_cb(struct lejp_ctx *ctx, char reason)
 		lws_b64_decode_stateful(&a->b64, ctx->buf, &inl,
 					a->p + a->count, &outl,
 					reason == LEJPCB_VAL_STR_END);
-		a->count += outl;
+		a->count += (int)outl;
 		if (inl != ctx->npos) {
 			lwsl_err("%s: b64 decode fail\n", __func__);
 			goto oom;
@@ -766,7 +766,7 @@ lws_ss_policy_parse(struct lws_context *context, const uint8_t *buf, size_t len)
 	struct policy_cb_args *args = (struct policy_cb_args *)context->pol_args;
 	int m;
 
-	m = (int)(signed char)lejp_parse(&args->jctx, buf, len);
+	m = (int)(signed char)lejp_parse(&args->jctx, buf, (int)len);
 	if (m == LEJP_CONTINUE || m >= 0)
 		return m;
 
diff --git a/lib/secure-streams/private-lib-secure-streams.h b/lib/secure-streams/private-lib-secure-streams.h
index 514307f7f..02e607f65 100644
--- a/lib/secure-streams/private-lib-secure-streams.h
+++ b/lib/secure-streams/private-lib-secure-streams.h
@@ -92,10 +92,19 @@ typedef struct lws_ss_handle {
 
 			union {
 				struct { /* LWSSSP_H1 */
+#if defined(WIN32)
+					uint8_t dummy;
+#endif
 				} h1;
 				struct { /* LWSSSP_H2 */
+#if defined(WIN32)
+					uint8_t dummy;
+#endif
 				} h2;
 				struct { /* LWSSSP_WS */
+#if defined(WIN32)
+					uint8_t dummy;
+#endif
 				} ws;
 			} u;
 		} http;
@@ -132,6 +141,10 @@ typedef struct lws_ss_handle {
 union lws_ss_contemp {
 #if defined(LWS_ROLE_MQTT)
 	lws_mqtt_client_connect_param_t ccp;
+#else
+#if defined(WIN32)
+	uint8_t	dummy;
+#endif
 #endif
 };
 
@@ -363,9 +376,9 @@ struct ss_pcols {
 	const char					*name;
 	const char					*alpn;
 	const char					*protocol_name;
-	const secstream_protocol_connect_munge_t	munge;
-	const secstream_protocol_add_txcr_t		tx_cr_add;
-	const secstream_protocol_get_txcr_t		tx_cr_est;
+	secstream_protocol_connect_munge_t		munge;
+	secstream_protocol_add_txcr_t			tx_cr_add;
+	secstream_protocol_get_txcr_t			tx_cr_est;
 };
 
 extern const struct ss_pcols ss_pcol_h1;
diff --git a/lib/secure-streams/protocols/ss-h1.c b/lib/secure-streams/protocols/ss-h1.c
index 81065a334..2daf8747f 100644
--- a/lib/secure-streams/protocols/ss-h1.c
+++ b/lib/secure-streams/protocols/ss-h1.c
@@ -272,7 +272,8 @@ secstream_h1(struct lws *wsi, enum lws_callback_reasons reason, void *user,
 					lws_strnncpy(h->u.http.boundary + 4,
 						     ts.token, ts.token_len,
 						     sizeof(h->u.http.boundary) - 4);
-					h->u.http.boundary_len = ts.token_len + 4;
+					h->u.http.boundary_len =
+						(uint8_t)(ts.token_len + 4);
 					h->u.http.boundary_seq = 2;
 					h->u.http.boundary_dashes = 0;
 				}
@@ -334,7 +335,7 @@ malformed:
 
 			if (lws_add_http_header_by_name(wsi,
 					 (uint8_t *)h->policy->u.http.blob_header[m],
-					 buf, buflen + o, p, end))
+					 buf, (int)(buflen + o), p, end))
 				return -1;
 		}
 
@@ -357,7 +358,7 @@ malformed:
 				if (lws_add_http_header_by_name(wsi,
 						polmd->value,
 						h->metadata[m].value,
-						h->metadata[m].length, p, end))
+						(int)h->metadata[m].length, p, end))
 				return -1;
 			}
 		}
diff --git a/lib/secure-streams/system/auth-api.amazon.com/auth.c b/lib/secure-streams/system/auth-api.amazon.com/auth.c
index 697ae77b4..7e3d6d4e1 100644
--- a/lib/secure-streams/system/auth-api.amazon.com/auth.c
+++ b/lib/secure-streams/system/auth-api.amazon.com/auth.c
@@ -126,7 +126,7 @@ ss_api_amazon_auth_rx(void *userobj, const uint8_t *buf, size_t len, int flags)
 			lws_system_blob_heap_empty(ab);
 		}
 
-		n = (int)(signed char)lejp_parse(&m->jctx, buf, len);
+		n = (int)(signed char)lejp_parse(&m->jctx, buf, (int)len);
 		if (n < 0) {
 			lejp_destruct(&m->jctx);
 			lws_system_blob_destroy(
@@ -205,7 +205,7 @@ ss_api_amazon_auth_state(void *userobj, void *sh, lws_ss_constate_t state,
 		s = lws_system_blob_get_size(
 			lws_system_get_blob(context, LWS_SYSBLOB_TYPE_AUTH,
 					    AUTH_IDX_ROOT));
-		lws_ss_request_tx_len(m->ss, s);
+		lws_ss_request_tx_len(m->ss, (unsigned long)s);
 		m->pos = 0;
 		break;