diff --git a/lib/deserializer.js b/lib/deserializer.js
index 0b22eb2..bc1cceb 100644
--- a/lib/deserializer.js
+++ b/lib/deserializer.js
@@ -24,14 +24,14 @@ function defaultAfterDeserialize (options, cb) {
 module.exports = function deserializer (options, cb) {
   var model = options.model
 
-  var beforeDeserialize = (typeof model.beforeJsonApiDeserialize === 'function') ?
-    model.beforeJsonApiDeserialize : defaultBeforeDeserialize
+  var beforeDeserialize = (typeof model.beforeJsonApiDeserialize === 'function')
+    ? model.beforeJsonApiDeserialize : defaultBeforeDeserialize
 
-  var deserialize = (typeof model.jsonApiDeserialize === 'function') ?
-    model.jsonApiDeserialize : defaultDeserialize
+  var deserialize = (typeof model.jsonApiDeserialize === 'function')
+    ? model.jsonApiDeserialize : defaultDeserialize
 
-  var afterDeserialize = (typeof model.afterJsonApiDeserialize === 'function') ?
-    model.afterJsonApiDeserialize : defaultAfterDeserialize
+  var afterDeserialize = (typeof model.afterJsonApiDeserialize === 'function')
+    ? model.afterJsonApiDeserialize : defaultAfterDeserialize
 
   var deserializeOptions = _.cloneDeep(options)
 
diff --git a/lib/relationships.js b/lib/relationships.js
index 0d3375c..fb3999f 100644
--- a/lib/relationships.js
+++ b/lib/relationships.js
@@ -2,6 +2,7 @@
 
 var _ = require('lodash')
 var utils = require('./utils')
+var debug = require('debug')('loopback-component-jsonapi')
 
 module.exports = function (app, options) {
   // get remote methods.
@@ -100,6 +101,40 @@ function relationships (id, data, model) {
 
         updateRelation(modelTo, idToFind, where)
       })
+
+      if (serverRelation.modelThrough) {
+        var modelThrough = serverRelation.modelThrough
+        var key = keyByModel(modelThrough, modelTo)
+        var data = {}
+        data[fkName] = id
+        var stringIds = false
+
+        var payloadIds = _.map(relationship.data, function (item) {
+          if (typeof item.id === 'string') {
+            stringIds = true
+          }
+          return item.id
+        })
+
+        modelThrough.find({where: data, fields: key}, function(err, instances) {
+          if (err) return
+          var serverIds = _.map(instances, function(instance) {
+            return stringIds ? instance[key].toString() : instance[key]
+          })
+          // to delete
+          var toDelete = _.difference(serverIds, payloadIds)
+          _.each(toDelete, function (id) {
+            data[key] = id
+            modelThrough.destroyAll(data)
+          })
+          // new
+          var newAssocs = _.difference(payloadIds, serverIds)
+          _.each(newAssocs, function (id) {
+            data[key] = id
+            modelThrough.create(data)
+          })
+        })
+      }
     } else {
       if (relationship.data === null) {
         where[fkName] = null
@@ -132,3 +167,17 @@ function updateRelation (model, id, data) {
     }
   })
 }
+
+function keyByModel (assocModel, model) {
+  var key = null
+  _.each(assocModel.relations, function (relation) {
+    if (relation.modelTo.modelName === model.modelName) {
+      key = relation.keyFrom
+    }
+  })
+
+  if (key === null) {
+    debug('Can not find relation for ' + model.modelName)
+  }
+  return key
+}
diff --git a/package.json b/package.json
index d20e69b..1a1e2d4 100644
--- a/package.json
+++ b/package.json
@@ -6,7 +6,7 @@
     "test": "npm run lint && istanbul cover _mocha --report lcovonly --reporter=spec ./test/**/*.test.js && cat ./coverage/lcov.info | ./node_modules/coveralls/bin/coveralls.js && rm -rf ./coverage",
     "tester": "mocha --reporter=spec ./test/**/*.test.js",
     "coverage": "istanbul cover _mocha ./test/**/*.test.js",
-    "lint": "standard .",
+    "lint": "standard ./test/**/*.js ./lib/**/*.js --verbose | snazzy",
     "semantic-release": "semantic-release pre && npm publish && semantic-release post"
   },
   "repository": {
@@ -32,6 +32,7 @@
     "http-status-codes": "^1.0.5",
     "inflection": "^1.7.2",
     "lodash": "^4.17.1",
+    "snazzy": "^7.0.0",
     "type-is": "^1.6.14"
   },
   "devDependencies": {
diff --git a/test/hasManyThroughUpsert.test.js b/test/hasManyThroughUpsert.test.js
new file mode 100644
index 0000000..a6e7e88
--- /dev/null
+++ b/test/hasManyThroughUpsert.test.js
@@ -0,0 +1,205 @@
+/* global describe, beforeEach, it */
+
+var request = require('supertest')
+var loopback = require('loopback')
+var expect = require('chai').expect
+var JSONAPIComponent = require('../')
+var RSVP = require('rsvp')
+
+var app
+var Movie, Category, MovieCategoryAssoc
+
+describe('hasManyThrough upsert', function () {
+  beforeEach(function (done) {
+    app = loopback()
+    app.set('legacyExplorer', false)
+    var ds = loopback.createDataSource('memory')
+    // create models
+    Movie = ds.createModel('movie', {
+      id: { type: Number, id: true },
+      name: String
+    })
+
+    Category = ds.createModel('category', {
+      id: { type: Number, id: true },
+      name: String
+    })
+
+    MovieCategoryAssoc = ds.createModel('movieCategoryAssoc', {
+      id: { type: Number, id: true }
+    })
+
+    // add models
+    app.model(Movie)
+    app.model(Category)
+    app.model(MovieCategoryAssoc)
+
+    // set up relationships
+    Movie.hasMany(Category, { through: MovieCategoryAssoc })
+    Category.hasMany(Movie, { through: MovieCategoryAssoc })
+
+    MovieCategoryAssoc.belongsTo(Movie)
+    MovieCategoryAssoc.belongsTo(Category)
+    makeData()
+      .then(function () {
+        done()
+      })
+      .catch(function (err) {
+        done(err)
+      })
+    app.use(loopback.rest())
+    JSONAPIComponent(app, { restApiRoot: '' })
+  })
+
+  it('should make initial data', function (done) {
+    request(app).get('/movies/1/categories').end(function (err, res) {
+      expect(err).to.equal(null)
+      expect(res.body.data.length).to.equal(2)
+      expect(res.body.data[0].attributes.name).to.equal('Crime')
+      done(err)
+    })
+  })
+
+  it('should handle POST', function (done) {
+    var agent = request(app)
+    agent
+      .post('/movies')
+      .send({
+        data: {
+          type: 'movies',
+          attributes: {
+            name: 'Ace Ventura: Pet Detective'
+          },
+          relationships: {
+            categories: {
+              data: [{ type: 'categories', id: 4 }]
+            }
+          }
+        }
+      })
+      .end(function () {
+        agent.get('/movieCategoryAssocs').end(function (err, res) {
+          expect(err).to.equal(null)
+          expect(res.body.data.length).to.equal(3)
+          done()
+        })
+      })
+  })
+
+  it('should handle PATCH', function (done) {
+    var agent = request(app)
+    agent
+      .patch('/movies/1')
+      .send({
+        data: {
+          id: 1,
+          type: 'movies',
+          attributes: {
+            name: 'The Shawshank Redemption'
+          },
+          relationships: {
+            categories: {
+              data: [
+                { type: 'categories', id: 1 },
+                { type: 'categories', id: 2 },
+                { type: 'categories', id: 3 }
+              ]
+            }
+          }
+        }
+      })
+      .end(function () {
+        agent.get('/movieCategoryAssocs').end(function (err, res) {
+          expect(err).to.equal(null)
+          expect(res.body.data.length).to.equal(3)
+          done()
+        })
+      })
+  })
+
+  it('should handle string IDs', function (done) {
+    var agent = request(app)
+    agent
+      .patch('/movies/1')
+      .send({
+        data: {
+          id: '1',
+          type: 'movies',
+          attributes: {
+            name: 'The Shawshank Redemption'
+          },
+          relationships: {
+            categories: {
+              data: [{ type: 'categories', id: '1' }, { type: 'categories', id: '4' }]
+            }
+          }
+        }
+      })
+      .end(function () {
+        agent.get('/movieCategoryAssocs/1').end(function (err, res) {
+          expect(err).to.equal(null)
+          expect(res.body.data.id).to.equal('1')
+          done()
+        })
+      })
+  })
+
+  it('should handle PATCH with less assocs', function (done) {
+    var agent = request(app)
+    agent
+      .patch('/movies/1')
+      .send({
+        data: {
+          id: 1,
+          type: 'movies',
+          attributes: {
+            name: 'The Shawshank Redemption'
+          },
+          relationships: {
+            categories: {
+              data: [{ type: 'categories', id: 1 }, { type: 'categories', id: 4 }]
+            }
+          }
+        }
+      })
+      .end(function (err, res) {
+        expect(err).to.equal(null)
+        agent.get('/movieCategoryAssocs').end(function (err, res) {
+          expect(err).to.equal(null)
+          expect(res.body.data.length).to.equal(2)
+
+          agent.get('/movies/1/categories').end(function (err, res) {
+            expect(err).to.equal(null)
+            expect(res.body.data.length).to.equal(2)
+            expect(res.body.data[1].attributes.name).to.equal('Comedy')
+            done()
+          })
+        })
+      })
+  })
+})
+
+function makeData () {
+  var createMovie = denodeifyCreate(Movie)
+  var createCategory = denodeifyCreate(Category)
+  var createAssoc = denodeifyCreate(MovieCategoryAssoc)
+
+  return RSVP.hash({
+    movie: createMovie({ name: 'The Shawshank Redemption' }),
+    categories: RSVP.all([
+      createCategory({ name: 'Crime' }),
+      createCategory({ name: 'Drama' }),
+      createCategory({ name: 'History' }),
+      createCategory({ name: 'Comedy' })
+    ])
+  }).then(function (models) {
+    return RSVP.all([
+      createAssoc({ movieId: models.movie.id, categoryId: models.categories[0].id }),
+      createAssoc({ movieId: models.movie.id, categoryId: models.categories[2].id })
+    ])
+  })
+
+  function denodeifyCreate (Model) {
+    return RSVP.denodeify(Model.create.bind(Model))
+  }
+}