diff --git a/spec-nylas/tasks/change-mail-task-spec.coffee b/spec-nylas/tasks/change-mail-task-spec.coffee
index 74044b86e..a786cc1aa 100644
--- a/spec-nylas/tasks/change-mail-task-spec.coffee
+++ b/spec-nylas/tasks/change-mail-task-spec.coffee
@@ -354,13 +354,67 @@ describe "ChangeMailTask", ->
           new Promise (resolve, reject) -> #noop
         spyOn(@task, '_removeLock')
         runs ->
-          @task.performRequests(Message, [@threadAMesage1])
+          @task.performRequests(Thread, [@threadAMesage1])
         waitsFor ->
           NylasAPI.makeRequest.callCount is 1
         runs ->
           NylasAPI.makeRequest.calls[0].args[0].beforeProcessing({})
           expect(@task._removeLock).toHaveBeenCalledWith(@threadAMesage1)
 
+      it "should make no more than 10 requests at once", ->
+        resolves = []
+        spyOn(@task, '_removeLock')
+        spyOn(NylasAPI, 'makeRequest').andCallFake ->
+          new Promise (resolve, reject) -> resolves.push(resolve)
+
+        threads = []
+        threads.push new Thread(id: "#{idx}", subject: idx) for idx in [0..100]
+        @task._restoreValues = _.map threads, (t) -> {some: 'data'}
+        @task.performRequests(Thread, threads)
+        advanceClock()
+        expect(resolves.length).toEqual(5)
+        advanceClock()
+        expect(resolves.length).toEqual(5)
+        resolves[0]()
+        resolves[1]()
+        advanceClock()
+        expect(resolves.length).toEqual(7)
+        resolves[idx]() for idx in [2...7]
+        advanceClock()
+        expect(resolves.length).toEqual(12)
+
+
+      it "should stop making requests after non-404 network errors", ->
+        resolves = []
+        rejects = []
+        spyOn(@task, '_removeLock')
+        spyOn(NylasAPI, 'makeRequest').andCallFake ->
+          new Promise (resolve, reject) ->
+            resolves.push(resolve)
+            rejects.push(reject)
+
+        threads = []
+        threads.push new Thread(id: "#{idx}", subject: idx) for idx in [0..100]
+        @task._restoreValues = _.map threads, (t) -> {some: 'data'}
+        @task.performRequests(Thread, threads)
+        advanceClock()
+        expect(resolves.length).toEqual(5)
+        resolves[idx]() for idx in [0...4]
+        advanceClock()
+        expect(resolves.length).toEqual(9)
+
+        # simulate request failure
+        reject = rejects[rejects.length - 1]
+        reject(new APIError(statusCode: 400))
+        advanceClock()
+
+        # simulate more requests succeeding
+        resolves[idx]() for idx in [5...9]
+        advanceClock()
+
+        # check that no more requests have been queued
+        expect(resolves.length).toEqual(9)
+
   describe "optimistic object locking", ->
     beforeEach ->
       @task = new ChangeMailTask()
diff --git a/src/flux/tasks/change-mail-task.coffee b/src/flux/tasks/change-mail-task.coffee
index 5a11a569f..1f5b5a121 100644
--- a/src/flux/tasks/change-mail-task.coffee
+++ b/src/flux/tasks/change-mail-task.coffee
@@ -7,6 +7,40 @@ DatabaseStore = require '../stores/database-store'
 AccountStore = require '../stores/account-store'
 {APIError} = require '../errors'
 
+# MapLimit is a small helper method that implements a promise version of
+# Async.mapLimit. It runs the provided fn on each item in the `input` array,
+# but only runs `numberInParallel` copies of `fn` at a time, resolving
+# with an output array, or rejecting with an error if any execution of
+# `fn` returns an error.
+mapLimit = (input, numberInParallel, fn) ->
+  new Promise (resolve, reject) ->
+    idx = 0
+    inflight = 0
+    output = []
+    outputError = null
+
+    startNext = ->
+      startIdx = idx
+      idx += 1
+      inflight += 1
+      fn(input[startIdx])
+      .then (result) =>
+        output[startIdx] = result
+        return if outputError
+
+        inflight -= 1
+        if idx < input.length
+          startNext()
+        else if inflight is 0
+          resolve(output)
+
+      .catch (err) =>
+        outputError = err
+        reject(outputError)
+
+    numberInParallel = Math.min(numberInParallel, input.length)
+    startNext() for n in [0...numberInParallel]
+
 # The ChangeMailTask is a base class for all tasks that modify sets of threads or
 # messages. Subclasses implement `_changesToModel` and `_requestBodyForModel` to
 # define the specific transforms they provide, and override `performLocal` to
@@ -130,7 +164,7 @@ class ChangeMailTask extends Task
         return Promise.resolve(Task.Status.Retry)
 
   performRequests: (klass, models) ->
-    Promise.map models, (model) =>
+    mapLimit models, 5, (model) =>
       # Don't bother making a web request if performLocal didn't modify this model
       return Promise.resolve() unless @_restoreValues[model.id]