diff --git a/src/ssb.js.c b/src/ssb.js.c
index 9b306604..3b9b62fb 100644
--- a/src/ssb.js.c
+++ b/src/ssb.js.c
@@ -108,13 +108,60 @@ static JSValue _tf_ssb_createIdentity(JSContext* context, JSValueConst this_val,
 	return result;
 }
 
+typedef struct _add_identity_t
+{
+	uint8_t key[crypto_sign_SECRETKEYBYTES / 2];
+	bool added;
+	JSValue promise[2];
+	char user[];
+} add_identity_t;
+
+static void _tf_ssb_add_identity_work(tf_ssb_t* ssb, void* user_data)
+{
+	add_identity_t* work = user_data;
+	uint8_t public_key[crypto_sign_PUBLICKEYBYTES];
+	unsigned char seed[crypto_sign_SEEDBYTES];
+	uint8_t secret_key[crypto_sign_SECRETKEYBYTES] = { 0 };
+	memcpy(secret_key, work->key, sizeof(secret_key) / 2);
+	if (crypto_sign_ed25519_sk_to_seed(seed, secret_key) == 0 && crypto_sign_seed_keypair(public_key, secret_key, seed) == 0)
+	{
+		char public_key_b64[512];
+		tf_base64_encode(public_key, sizeof(public_key), public_key_b64, sizeof(public_key_b64));
+		snprintf(public_key_b64 + strlen(public_key_b64), sizeof(public_key_b64) - strlen(public_key_b64), ".ed25519");
+
+		uint8_t combined[crypto_sign_SECRETKEYBYTES];
+		memcpy(combined, work->key, sizeof(work->key));
+		memcpy(combined + sizeof(work->key), public_key, sizeof(public_key));
+		char combined_b64[512];
+		tf_base64_encode(combined, sizeof(combined), combined_b64, sizeof(combined_b64));
+		snprintf(combined_b64 + strlen(combined_b64), sizeof(combined_b64) - strlen(combined_b64), ".ed25519");
+
+		work->added = tf_ssb_db_identity_add(ssb, work->user, public_key_b64, combined_b64);
+	}
+}
+
+static void _tf_ssb_add_identity_after_work(tf_ssb_t* ssb, int status, void* user_data)
+{
+	add_identity_t* work = user_data;
+	JSContext* context = tf_ssb_get_context(ssb);
+	JSValue result = work->added ? JS_TRUE : JS_UNDEFINED;
+	JSValue error = JS_Call(context, work->promise[0], JS_UNDEFINED, 1, &result);
+	JS_FreeValue(context, result);
+	tf_util_report_error(context, error);
+	JS_FreeValue(context, error);
+	JS_FreeValue(context, work->promise[0]);
+	JS_FreeValue(context, work->promise[1]);
+	tf_free(work);
+}
+
 static JSValue _tf_ssb_addIdentity(JSContext* context, JSValueConst this_val, int argc, JSValueConst* argv)
 {
 	tf_ssb_t* ssb = JS_GetOpaque(this_val, _tf_ssb_classId);
 	JSValue result = JS_UNDEFINED;
 	if (ssb)
 	{
-		const char* user = JS_ToCString(context, argv[0]);
+		size_t user_length = 0;
+		const char* user = JS_ToCStringLen(context, &user_length, argv[0]);
 
 		JSValue buffer = JS_UNDEFINED;
 		size_t length = 0;
@@ -134,50 +181,25 @@ static JSValue _tf_ssb_addIdentity(JSContext* context, JSValueConst this_val, in
 		{
 			if (length == crypto_sign_SECRETKEYBYTES / 2)
 			{
-				uint8_t public_key[crypto_sign_PUBLICKEYBYTES];
-				unsigned char seed[crypto_sign_SEEDBYTES];
-				uint8_t secret_key[crypto_sign_SECRETKEYBYTES] = { 0 };
-				memcpy(secret_key, array, sizeof(secret_key) / 2);
-				if (crypto_sign_ed25519_sk_to_seed(seed, secret_key) == 0 && crypto_sign_seed_keypair(public_key, secret_key, seed) == 0)
-				{
-					char public_key_b64[512];
-					tf_base64_encode(public_key, sizeof(public_key), public_key_b64, sizeof(public_key_b64));
-					snprintf(public_key_b64 + strlen(public_key_b64), sizeof(public_key_b64) - strlen(public_key_b64), ".ed25519");
-
-					uint8_t combined[crypto_sign_SECRETKEYBYTES];
-					memcpy(combined, array, length);
-					memcpy(combined + length, public_key, sizeof(public_key));
-					char combined_b64[512];
-					tf_base64_encode(combined, sizeof(combined), combined_b64, sizeof(combined_b64));
-					snprintf(combined_b64 + strlen(combined_b64), sizeof(combined_b64) - strlen(combined_b64), ".ed25519");
-
-					if (tf_ssb_db_identity_add(ssb, user, public_key_b64, combined_b64))
-					{
-						result = JS_TRUE;
-					}
-					else
-					{
-						tf_printf("Unable to add the identity.");
-					}
-				}
+				add_identity_t* work = tf_malloc(sizeof(add_identity_t) + user_length + 1);
+				*work = (add_identity_t) { 0 };
+				memcpy(work->key, array, sizeof(work->key));
+				memcpy(work->user, user, user_length + 1);
+				result = JS_NewPromiseCapability(context, work->promise);
+				tf_ssb_run_work(ssb, _tf_ssb_add_identity_work, _tf_ssb_add_identity_after_work, work);
 			}
 			else
 			{
-				tf_printf("Unexpected private key size: %zd vs. %d\n", length, crypto_sign_SECRETKEYBYTES);
+				result = JS_ThrowInternalError(context, "Unexpected private key size: %zd vs. %d\n", length, crypto_sign_SECRETKEYBYTES);
 			}
 		}
 		else
 		{
-			tf_printf("didn't find array\n");
+			result = JS_ThrowInternalError(context, "Expected array argument.");
 		}
 		JS_FreeValue(context, buffer);
-
 		JS_FreeCString(context, user);
 	}
-	else
-	{
-		tf_printf("no ssb\n");
-	}
 	return result;
 }