diff --git a/tests/runtime/in_http.c b/tests/runtime/in_http.c
index 85eef206e34..8e384908dbd 100644
--- a/tests/runtime/in_http.c
+++ b/tests/runtime/in_http.c
@@ -361,10 +361,84 @@ void flb_test_http_successful_response_code_204()
     flb_test_http_successful_response_code("204");    
 }
 
+void flb_test_http_tag_key()
+{
+    struct flb_lib_out_cb cb_data;
+    struct test_ctx *ctx;
+    struct flb_http_client *c;
+    int ret;
+    int num;
+    size_t b_sent;
+
+    char *buf = "{\"test\":\"msg\", \"tag\":\"new_tag\"}";
+
+    clear_output_num();
+
+    cb_data.cb = cb_check_result_json;
+    cb_data.data = "\"test\":\"msg\"";
+
+    ctx = test_ctx_create(&cb_data);
+    if (!TEST_CHECK(ctx != NULL)) {
+        TEST_MSG("test_ctx_create failed");
+        exit(EXIT_FAILURE);
+    }
+
+    ret = flb_input_set(ctx->flb, ctx->i_ffd,
+                        "tag_key", "tag",
+                        NULL);
+    TEST_CHECK(ret == 0);
+
+    ret = flb_output_set(ctx->flb, ctx->o_ffd,
+                         "match", "new_tag",
+                         "format", "json",
+                         NULL);
+    TEST_CHECK(ret == 0);
+
+    /* Start the engine */
+    ret = flb_start(ctx->flb);
+    TEST_CHECK(ret == 0);
+
+    ctx->httpc = http_client_ctx_create();
+    TEST_CHECK(ctx->httpc != NULL);
+
+    c = flb_http_client(ctx->httpc->u_conn, FLB_HTTP_POST, "/", buf, strlen(buf),
+                        "127.0.0.1", 9880, NULL, 0);
+    ret = flb_http_add_header(c, FLB_HTTP_HEADER_CONTENT_TYPE, strlen(FLB_HTTP_HEADER_CONTENT_TYPE),
+                              JSON_CONTENT_TYPE, strlen(JSON_CONTENT_TYPE));
+    TEST_CHECK(ret == 0);
+    if (!TEST_CHECK(c != NULL)) {
+        TEST_MSG("http_client failed");
+        exit(EXIT_FAILURE);
+    }
+
+    ret = flb_http_do(c, &b_sent);
+    if (!TEST_CHECK(ret == 0)) {
+        TEST_MSG("ret error. ret=%d\n", ret);
+    }
+    else if (!TEST_CHECK(b_sent > 0)){
+        TEST_MSG("b_sent size error. b_sent = %lu\n", b_sent);
+    }
+    else if (!TEST_CHECK(c->resp.status == 201)) {
+        TEST_MSG("http response code error. expect: 201, got: %d\n", c->resp.status);
+    }
+
+    /* waiting to flush */
+    flb_time_msleep(1500);
+
+    num = get_output_num();
+    if (!TEST_CHECK(num > 0))  {
+        TEST_MSG("no outputs");
+    }
+    flb_http_client_destroy(c);
+    flb_upstream_conn_release(ctx->httpc->u_conn);
+    test_ctx_destroy(ctx);
+}
+
 TEST_LIST = {
     {"http", flb_test_http},
     {"successful_response_code_200", flb_test_http_successful_response_code_200},
     {"successful_response_code_204", flb_test_http_successful_response_code_204},
+    {"tag_key", flb_test_http_tag_key},
     {NULL, NULL}
 };