AFNetworking and NSMutableURLRequest generate a request with params.

requestwithafnetworking.m

/*
Generate a request with params.

POST /post/url
Host: www.example.com
Content-Type: application/x-www-form-urlencoded; charset=utf-8

uuid=12345-ABC-9876-XYZ&first_name=john&last_name=doe
*/

NSString *urlString = @"http://www.example.com/post/url";
NSURL *baseURL = [NSURL URLWithString:urlString];

AFHTTPClient *httpClient = [[AFHTTPClient alloc] initWithBaseURL:baseURL];
[httpClient defaultValueForHeader:@"Accept"];

NSDictionary *params = [NSDictionary dictionaryWithObjectsAndKeys:
                                @"12345-ABC-9876-XYZ", @"uuid",
                                @"john", @"first_name",
                                @"doe", @"last_name",
                                nil];

NSMutableURLRequest *request = [httpClient requestWithMethod: @"POST" path: urlString parameters: params];
NSLog(@"%@", [request description]);

AFHTTPRequestOperation *operation = [[AFHTTPRequestOperation alloc] initWithRequest: request];
[httpClient registerHTTPOperationClass:[AFHTTPRequestOperation class]];
[operation setCompletionBlockWithSuccess: ^(AFHTTPRequestOperation *operation, id responseObject) {
    NSString *response = [operation responseString];
    NSLog(@"response: [%@]", response);
    // Manage response from server here.
} failure:^(AFHTTPRequestOperation *operation, NSError *error) {
	NSLog(@"error: %@", [operation error]);
}];

[operation start];