gRPC body messae is being altered using postman

Postman is altering the request body

I’m using postman to test a gRPC API and I’m using a nested json object like this:

"data": {
            "fields": [
                {
                    "key": "general_key",
                    "value": {
                        "struct_value": {
                            "list_keys": [
                                {
                                    "key": "key 1",
                                    "value": {
                                        "string_value": "1"
                                    }
                                }
                            ]
                        }
                    }
                }
            ]
        }

However, the server what is receiving is a wrong value for “list_keys” list. Instead of receiving a list of JSON documents (key 1, and key2), I’m getting a dictionary:

  data {
    fields {
      key: "list_keys"
      value {
        struct_value {
          fields {
            key: "0"
            value {
            }
          }
        }
      }
    }
  }

I’ve confirmed that this is happening only with Postman, with other applications, I get the correct JSON document in the backend:

document_data {
    fields {
      key: "general_key"
      value {
        list_value {
          values {
            struct_value {
              fields {
                key: "key"
                value {
                  string_value: "list_keys"
                }
              }
              fields {
                key: "value"
                value {
                  struct_value {
                    fields {
                      key: "struct_value"
                      value {
                        struct_value {
                          fields {
                            key: "fields"
                            value {
                              list_value {
                                values {
                                  struct_value {
                                    fields {
                                      key: "key"
                                      value {
                                        string_value: "key 1"
                                      }
                                    }
                                    fields {
                                      key: "value"
                                      value {
                                        struct_value {
                                          fields {
                                            key: "string_value"
                                            value {
                                              string_value: "1"
                                            }
                                          }
                                        }
                                      }
                                    }
                                  }
                                }
                              }
                            }
                          }
                        }
                      }
                    }
                  }
                }
              }
            }
          }
        }
      }
    }
  }

Does anyone have an idea of why postman is altering the request body?

–Thanks