If you wish to access multiple attachments records you would normally use the attachmentslist model.

For more details about using models see Using data models

For activities two models are available:

attachmentslist
attachmentdetails

Parameter	Description	Example	More info
API	The API area	attachments.json
Action	Not required
General	Parameters described in overview	user=user&password=user&version=3.1	v3.1 Overview
Modelstructure	Name of model required	Modelstructure=attachmentsList	Using models & views
View	Stored filter applied	view=-1700	Using views
Filters	Filter by a key field	client=1/F667	Filters
Response	Returned data	A JSON string containing the data

Example

Request for data (list of records using specified model)

http://<SERVER>/jsonapi/attachments.json?company=1&version=3.1&user=user&password=user&style=modeldata&modelstructure=attachmentsList&rows=2&page=1

{
  "responsecode": 1,
  "responsestatus": "OK",
  "errorcode": 0,
  "errormessage": "",
  "totalrows": 2,
  "totalpages": 1,
  "responsemessage": "",
  "pagerows": 0,
  "pagenumber": 1,
  "success": true,
  "data": [
    {
      "attachmentUuid": "A25519AD6B32BA4A8AD0FC7F5B647E75",
      "attachmentTimestampModified": 1501072436,
      "attachmentRecordVersionNumber": 0,
      "attachmentCreatedDisplay": "Created by Mike Smith Dev on 26/07/2017 at 1:33pm",
      "attachmentS3UrlGet": "",
      "attachmentS3UrlPut": "",
      "attachmentClientName": "Smith & Co",
      "attachmentActivityID": 6957,
      "attachmentID": 5463,
      "attachmentDocumentName": "temp_5463.csv",
      "attachmentJobAndPhase": "",
      "attachmentDescription": "temp.csv",
      "attachmentExtension": "CSV",
      "attachmentContainer": "My Meeting notesa",
      "attachmentCreationDate": "2017-07-26",
      "attachmentCreationTime": "13:33:56",
      "attachmentCreatedByUserID": 5,
      "attachmentCreatedByFullName": "Mike Smith",
      "attachmentMode": "Browse"
    },
    {
      "attachmentUuid": "5337C90967F1D94C83607D2724F7FB82",
      "attachmentTimestampModified": 1501073898,
      "attachmentRecordVersionNumber": 0,
      "attachmentCreatedDisplay": "Created by Jon Brown on 26/07/2017 at 1:58pm",
      "attachmentS3UrlGet": "",
      "attachmentS3UrlPut": "",
      "attachmentClientName": "Smith & Co",
      "attachmentActivityID": 6957,
      "attachmentID": 5466,
      "attachmentDocumentName": "special_5466.pdf",
      "attachmentJobAndPhase": "",
      "attachmentDescription": "Special.pdf",
      "attachmentExtension": "PDF",
      "attachmentContainer": "My Meeting notesa",
      "attachmentCreationDate": "2017-07-26",
      "attachmentCreationTime": "13:58:18",
      "attachmentCreatedByUserID": 3,
      "attachmentCreatedByFullName": "Jon Brown",
      "attachmentMode": "API"
    }
  ]
}