Thank you guys for the help. I've included the code that you guys have helped me with so it can be of help for those in the future.   Note about the api_key. Looking at the java sample that is posted to follow I see/saw no mention of even needing/using the api-key. I was just throwing everything I could think of at this and figured since the Bearer code went in the http header that maybe the api_key should also since it didn't appear to be needed. Although I do have to say I may have had it in the right place but had something else wrong at one point in all the tries I went thru before asking for help.     Either way I would like to thank you for the support.     VB.net VS 2010, framework 3.5   Imports  System.IO Imports  System.Text Imports  System.Collections.Specialized Private   Sub  FileUpload()          Dim  filename  As   String  =  ""          ' Added -- to boundary for simplicity          Dim  boundary  As   String  =  "--"  &  Guid .NewGuid().ToString()          ' The API key needs to be appended to the request URI          Dim  request  As   HttpWebRequest  =  TryCast ( HttpWebRequest .Create( "https://api.constantcontact.com/v2/activities/addcontacts?api_key=APIKEYHERE" ),  HttpWebRequest )         request.Method =  "POST"         request.ContentType =  String .Format( "multipart/form-data" )         request.Accept =  "application/json"          'request.PreAuthenticate = True         request.Headers.Add( "Authorization:  Bearer BEARERTOKEN" )  ' Add your Access Token here          ' I Also changed from AppendFormat for all lines to simply using AppendLine to shorten the content.           ' Feel free to change it back where you want to merge variables.         filename =  "C:\Development\constantcontact\emailkust.csv"          ' In order to get the request right, there are three request parts to add:          ' file_name - The filename          ' lists - comma separated list of list IDs          ' data - The actual file data          Dim  sb  As   New   StringBuilder ()         sb.AppendLine(boundary)         sb.AppendLine( "content-disposition: form-data; name=""file_name""" )         sb.AppendLine()         sb.AppendLine( "emailkust.csv" )  'filename         sb.AppendLine(boundary)         sb.AppendLine( "content-disposition: form-data; name=""lists""" )         sb.AppendLine()         sb.AppendLine( "1" )  ' List Number         sb.AppendLine(boundary)         sb.AppendLine( "content-disposition: file; name=""data"" filename=""emailkust.csv""" )         sb.AppendLine( "Content-Type: text/csv" )         sb.AppendLine()          Using  fs  As   New   FileStream (filename,  FileMode .Open,  FileAccess .Read)              Dim  contents  As   Byte () =  New   Byte (fs.Length - 1) {}             fs.Read(contents, 0, contents.Length)             sb.Append( Encoding .[Default].GetString(contents))          End   Using         sb.AppendLine(boundary &  "--" )          Dim  fulldata  As   Byte () =  Encoding .[Default].GetBytes(sb.ToString())          ' Uncomment the next line to dump the multipart request contents to a file for debugging.          ' My.Computer.FileSystem.WriteAllText("C:\constantcontact\test.txt", sb.ToString(), True)         request.ContentLength = fulldata.Length          Using  sw  As   Stream  = request.GetRequestStream()             sw.Write(fulldata, 0, fulldata.Length)          End   Using          ' Exception Handling was added so that I could display the error           Try              Dim  response  As   HttpWebResponse  =  TryCast (request.GetResponse(),  HttpWebResponse )              Using  sr  As   New   StreamReader (response.GetResponseStream())                  MessageBox .Show(sr.ReadToEnd())              End   Using          Catch  e  As   WebException              Using  sr  As   New   StreamReader (e.Response.GetResponseStream())                  MessageBox .Show( "Error Message:"  & e.Message & vbCr & vbLf &  "Error Body: "  & sr.ReadToEnd(),  "Web Error" ,  MessageBoxButtons .OK,  MessageBoxIcon .Error)              End   Using          End   Try      End   Sub   ... View more

It's nice that you guys will be adding it to the Github repository but I was wondering if you could look at my code and see what I'm doing wrong. It's VB.net. I think it's the whole Oauth with passing in the http headers thats the problem. Thanks a head of time.   Imports System.IO Imports System.Text Imports System.Collections.Specialized   Private Sub tyrout()         Dim filename As String = ""         Dim boundary As String = Guid.NewGuid().ToString()         Dim request As HttpWebRequest = TryCast(HttpWebRequest.Create("https://api.constantcontact.com/v2/activities/addcontacts"), HttpWebRequest)         request.Method = "POST"          request.ContentType = String.Format("multipart/form-data")         request.Accept = "application/json"         'request.PreAuthenticate = True         Dim sb As New StringBuilder()         sb.AppendFormat("--{0}", boundary)         sb.AppendFormat(vbCr & vbLf)         filename = "C:\Development\constantcontact\emailkust.csv"         sb.AppendFormat("Content-Disposition: form-data; name=""media""; filename=""" & filename & """")         sb.AppendFormat(vbCr & vbLf)         sb.AppendFormat("Authorization:  Bearer ") 'place the key from oauth here is my guess         sb.AppendFormat(vbCr & vbLf)             sb.AppendFormat("content-Type:  multipart/form-data")         sb.AppendFormat(vbCr & vbLf)         sb.AppendFormat("lists:  75") 'list number I guess is where it should go         sb.AppendFormat(vbCr & vbLf)         sb.AppendFormat("api_key: ") 'place the api key here I think or should it go on the http path?         sb.AppendFormat(vbCr & vbLf)         Using fs As New FileStream(filename, FileMode.Open, FileAccess.Read)              Dim contents As Byte() = New Byte(fs.Length - 1) {}             fs.Read(contents, 0, contents.Length)             sb.Append(Encoding.[Default].GetString(contents))         End Using         sb.AppendFormat(vbCr & vbLf)         sb.AppendFormat("--{0}--", boundary)         Dim fulldata As Byte() = Encoding.[Default].GetBytes(sb.ToString())         request.ContentLength = fulldata.Length         Using sw As Stream = request.GetRequestStream()             sw.Write(fulldata, 0, fulldata.Length)         End Using          Dim response As HttpWebResponse = TryCast(request.GetResponse(), HttpWebResponse)         Using sr As New StreamReader(response.GetResponseStream())             MessageBox.Show(sr.ReadToEnd())          End Using     End Sub   The csv file looks like this "EMAIL","LAST NAME","FIRST NAME" "1@one.org","1","1" "2@two.org","2","2" "3@three.org","3","3" "4@four.org","4","4" ... View more

Could you provide me with a sample in either C# or VB.net? I'm working at integrating with my windows form application and have no exprience with Java and having a problem. I could send you guys my vb.net code if you would like to see what I'm doing.   I'm tryign to do the bulk import file upload as suggested.   Thanks a head of time. ... View more

Have sent it off to the email to  webservices@constantcontact.com Looking forward to seeing what is going on.   let me know if you need any more specifics off of me. ... View more

I have a simular problem. I am sending first name,last name, and email using the builk actitivies add contacts v2/activities/addcontacts and it works fine until I increase the number of contacts that I send. In my testing I can get around 2,000 clients (156281 characters once all the json items are added)  with no problem but as soon as I increase it I get json error messages.    error_key: json.payload.invalid, error_message: Exception with request to: class com.roving.platform.domain.activities.addcontactsactivity    I know that the size that I'm sending (with 20,000 contacts with the josn) is 1,357,263 characters so if I'm rembering correctly the actual size in bytes is then twice that which is 2,714,526 bytes (2.5 mb) which is less than the 4mb in the limitations.   I'm using the information from  http://developer.constantcontact.com/docs/bulk_activities_api/bulk-activities-add-contacts.html )   I'm currently looking at your suggested builk activites multipart- add contacts multipart api but I would rather not do file uploads with the layer of file managment that would then be needed.   In way of testing is there any way that I could see exactly what the api is receiving by way of some kind of bounce back or echo in the responce. So I can exactly see what is being received. I have checked my controls that I'm using and they say the have no limits on the size but still just looking for more way to touble shoot this.   Thanks ahead of time.   Also I just verified that once I get to 200,000 characters the error happens which is a little more than 2,600 contacts. ... View more