diff --git a/Backend.Tests/Controllers/LiftControllerTests.cs b/Backend.Tests/Controllers/LiftControllerTests.cs
index 530e618a80..a2c7c5ccf6 100644
--- a/Backend.Tests/Controllers/LiftControllerTests.cs
+++ b/Backend.Tests/Controllers/LiftControllerTests.cs
@@ -314,8 +314,8 @@ public async Task TestDeletedWordsExportToLift()
             word.Id = "";
             word.Vernacular = "updated";
 
-            await _wordService.Update(_projId, wordToUpdate.Id, word);
-            await _wordService.DeleteFrontierWord(_projId, wordToDelete.Id);
+            await _wordService.Update(_projId, UserId, wordToUpdate.Id, word);
+            await _wordService.DeleteFrontierWord(_projId, UserId, wordToDelete.Id);
 
             await _liftController.CreateLiftExportThenSignal(_projId, UserId);
             var text = await DownloadAndReadLift(_liftController, _projId);
diff --git a/Backend.Tests/Controllers/WordControllerTests.cs b/Backend.Tests/Controllers/WordControllerTests.cs
index bc0226c802..a62c7c07a4 100644
--- a/Backend.Tests/Controllers/WordControllerTests.cs
+++ b/Backend.Tests/Controllers/WordControllerTests.cs
@@ -49,36 +49,6 @@ public void Setup()
             _projId = _projRepo.Create(new Project { Name = "WordControllerTests" }).Result!.Id;
         }
 
-        [Test]
-        public async Task TestDeleteAllWords()
-        {
-            await _wordRepo.Create(Util.RandomWord(_projId));
-            await _wordRepo.Create(Util.RandomWord(_projId));
-            const string diffProjId = "OTHER_PROJECT";
-            await _wordRepo.Create(Util.RandomWord(diffProjId));
-
-            await _wordController.DeleteProjectWords(_projId);
-            Assert.That(await _wordRepo.GetAllWords(_projId), Is.Empty);
-            Assert.That(await _wordRepo.GetFrontier(_projId), Is.Empty);
-            Assert.That(await _wordRepo.GetAllWords(diffProjId), Has.Count.EqualTo(1));
-            Assert.That(await _wordRepo.GetFrontier(diffProjId), Has.Count.EqualTo(1));
-        }
-
-        [Test]
-        public async Task TestDeleteAllWordsNoPermission()
-        {
-            _wordController.ControllerContext.HttpContext = PermissionServiceMock.UnauthorizedHttpContext();
-            var result = await _wordController.DeleteProjectWords(_projId);
-            Assert.That(result, Is.InstanceOf<ForbidResult>());
-        }
-
-        [Test]
-        public async Task TestDeleteAllWordsMissingProject()
-        {
-            var result = await _wordController.DeleteProjectWords(MissingId);
-            Assert.That(result, Is.InstanceOf<NotFoundObjectResult>());
-        }
-
         [Test]
         public async Task TestDeleteFrontierWord()
         {
@@ -275,7 +245,8 @@ public async Task TestUpdateDuplicate()
             var dupWord = origWord.Clone();
             dupWord.Flag = new Flag("New Flag");
             var expectedWord = dupWord.Clone();
-            var id = (string)((ObjectResult)await _wordController.UpdateDuplicate(_projId, origWord.Id, "", dupWord)).Value!;
+            var result = (ObjectResult)await _wordController.UpdateDuplicate(_projId, origWord.Id, dupWord);
+            var id = (string)result.Value!;
             var updatedWord = await _wordRepo.GetWord(_projId, id);
             Assert.That(expectedWord.ContentEquals(updatedWord!), Is.True);
         }
@@ -286,7 +257,7 @@ public async Task TestUpdateDuplicateNoPermission()
             _wordController.ControllerContext.HttpContext = PermissionServiceMock.UnauthorizedHttpContext();
 
             var word = await _wordRepo.Create(Util.RandomWord(_projId));
-            var result = await _wordController.UpdateDuplicate(_projId, word.Id, "", word);
+            var result = await _wordController.UpdateDuplicate(_projId, word.Id, word);
             Assert.That(result, Is.InstanceOf<ForbidResult>());
         }
 
@@ -294,7 +265,7 @@ public async Task TestUpdateDuplicateNoPermission()
         public async Task TestUpdateDuplicateMissingProject()
         {
             var word = await _wordRepo.Create(Util.RandomWord(_projId));
-            var result = await _wordController.UpdateDuplicate(MissingId, word.Id, "", word);
+            var result = await _wordController.UpdateDuplicate(MissingId, word.Id, word);
             Assert.That(result, Is.InstanceOf<NotFoundObjectResult>());
         }
 
@@ -302,7 +273,7 @@ public async Task TestUpdateDuplicateMissingProject()
         public async Task TestUpdateDuplicateMissingWord()
         {
             var word = Util.RandomWord(_projId);
-            var result = await _wordController.UpdateDuplicate(_projId, MissingId, "", word);
+            var result = await _wordController.UpdateDuplicate(_projId, MissingId, word);
             Assert.That(result, Is.InstanceOf<NotFoundObjectResult>());
         }
 
@@ -312,7 +283,7 @@ public async Task TestUpdateDuplicateNonDuplicate()
             var origWord = await _wordRepo.Create(Util.RandomWord(_projId));
             var nonDup = origWord.Clone();
             nonDup.Vernacular = "differentVern";
-            var result = await _wordController.UpdateDuplicate(_projId, origWord.Id, "", nonDup);
+            var result = await _wordController.UpdateDuplicate(_projId, origWord.Id, nonDup);
             Assert.That(result, Is.InstanceOf<ConflictResult>());
         }
 
diff --git a/Backend.Tests/Mocks/WordRepositoryMock.cs b/Backend.Tests/Mocks/WordRepositoryMock.cs
index fad84be28d..49a6ecaa1b 100644
--- a/Backend.Tests/Mocks/WordRepositoryMock.cs
+++ b/Backend.Tests/Mocks/WordRepositoryMock.cs
@@ -65,6 +65,11 @@ public Task<bool> IsFrontierNonempty(string projectId)
             return Task.FromResult(_frontier.Find(w => w.ProjectId == projectId) is not null);
         }
 
+        public Task<bool> IsInFrontier(string projectId, string wordId)
+        {
+            return Task.FromResult(_frontier.Find(w => w.ProjectId == projectId && w.Id == wordId) is not null);
+        }
+
         public Task<List<Word>> GetFrontier(string projectId)
         {
             return Task.FromResult(_frontier.Where(w => w.ProjectId == projectId).Select(w => w.Clone()).ToList());
diff --git a/Backend.Tests/Services/MergeServiceTests.cs b/Backend.Tests/Services/MergeServiceTests.cs
index c5373b552f..ab25ee2739 100644
--- a/Backend.Tests/Services/MergeServiceTests.cs
+++ b/Backend.Tests/Services/MergeServiceTests.cs
@@ -44,7 +44,7 @@ public void MergeWordsOneChildTest()
                 }
             };
 
-            var newWords = _mergeService.Merge(ProjId, new List<MergeWords> { mergeObject }).Result;
+            var newWords = _mergeService.Merge(ProjId, UserId, new List<MergeWords> { mergeObject }).Result;
 
             // There should only be 1 word added and it should be identical to what we passed in
             Assert.That(newWords, Has.Count.EqualTo(1));
@@ -76,7 +76,7 @@ public void MergeWordsDeleteTest()
                 DeleteOnly = true
             };
 
-            var newWords = _mergeService.Merge(ProjId, new List<MergeWords> { mergeObject }).Result;
+            var newWords = _mergeService.Merge(ProjId, UserId, new List<MergeWords> { mergeObject }).Result;
 
             // There should be no word added and no words left in the frontier.
             Assert.That(newWords, Is.Empty);
@@ -100,7 +100,7 @@ public void MergeWordsMultiChildTest()
             Assert.That(_wordRepo.GetFrontier(ProjId).Result, Has.Count.EqualTo(numberOfChildren));
 
             var mergeWordsList = new List<MergeWords> { mergeWords };
-            var newWords = _mergeService.Merge(ProjId, mergeWordsList).Result;
+            var newWords = _mergeService.Merge(ProjId, UserId, mergeWordsList).Result;
 
             // Check for correct history length.
             var dbParent = newWords.First();
@@ -117,7 +117,7 @@ public void MergeWordsMultipleTest()
             int wordCount = 100;
             var randWords = Util.RandomWordList(wordCount, ProjId);
             var mergeWordsList = randWords.Select(word => new MergeWords { Parent = word }).ToList();
-            var newWords = _mergeService.Merge(ProjId, mergeWordsList).Result;
+            var newWords = _mergeService.Merge(ProjId, UserId, mergeWordsList).Result;
 
             Assert.That(newWords, Has.Count.EqualTo(wordCount));
             Assert.That(newWords.First().Id, Is.Not.EqualTo(newWords.Last().Id));
@@ -144,7 +144,7 @@ public void UndoMergeOneChildTest()
                 }
             };
 
-            var newWords = _mergeService.Merge(ProjId, new List<MergeWords> { mergeObject }).Result;
+            var newWords = _mergeService.Merge(ProjId, UserId, new List<MergeWords> { mergeObject }).Result;
 
             // There should only be 1 word added and it should be identical to what we passed in
             Assert.That(newWords, Has.Count.EqualTo(1));
@@ -153,7 +153,7 @@ public void UndoMergeOneChildTest()
             var childIds = mergeObject.Children.Select(word => word.SrcWordId).ToList();
             var parentIds = new List<string> { newWords[0].Id };
             var mergedWord = new MergeUndoIds(parentIds, childIds);
-            var undo = _mergeService.UndoMerge(ProjId, mergedWord).Result;
+            var undo = _mergeService.UndoMerge(ProjId, UserId, mergedWord).Result;
             Assert.That(undo, Is.True);
 
             var frontierWords = _wordRepo.GetFrontier(ProjId).Result;
@@ -179,14 +179,14 @@ public void UndoMergeMultiChildTest()
             Assert.That(_wordRepo.GetFrontier(ProjId).Result, Has.Count.EqualTo(numberOfChildren));
 
             var mergeWordsList = new List<MergeWords> { mergeWords };
-            var newWords = _mergeService.Merge(ProjId, mergeWordsList).Result;
+            var newWords = _mergeService.Merge(ProjId, UserId, mergeWordsList).Result;
 
             Assert.That(_wordRepo.GetFrontier(ProjId).Result, Has.Count.EqualTo(1));
 
             var childIds = mergeWords.Children.Select(word => word.SrcWordId).ToList();
             var parentIds = new List<string> { newWords[0].Id };
             var mergedWord = new MergeUndoIds(parentIds, childIds);
-            var undo = _mergeService.UndoMerge(ProjId, mergedWord).Result;
+            var undo = _mergeService.UndoMerge(ProjId, UserId, mergedWord).Result;
             Assert.That(undo, Is.True);
 
             var frontierWords = _wordRepo.GetFrontier(ProjId).Result;
diff --git a/Backend.Tests/Services/WordServiceTests.cs b/Backend.Tests/Services/WordServiceTests.cs
index 2a01fbfbca..9d1ae31861 100644
--- a/Backend.Tests/Services/WordServiceTests.cs
+++ b/Backend.Tests/Services/WordServiceTests.cs
@@ -14,6 +14,8 @@ public class WordServiceTests
         private IWordService _wordService = null!;
 
         private const string ProjId = "WordServiceTestProjId";
+        private const string UserId = "WordServiceTestUserId";
+        private const string WordId = "WordServiceTestWordId";
 
         [SetUp]
         public void Setup()
@@ -22,6 +24,80 @@ public void Setup()
             _wordService = new WordService(_wordRepo);
         }
 
+        [Test]
+        public void TestCreateAddsUserId()
+        {
+            var word = _wordService.Create(UserId, new Word { EditedBy = new List<string> { "other" } }).Result;
+            Assert.That(word.EditedBy, Has.Count.EqualTo(2));
+            Assert.That(word.EditedBy.Last(), Is.EqualTo(UserId));
+        }
+
+        [Test]
+        public void TestCreateDoesNotAddDuplicateUserId()
+        {
+            var word = _wordService.Create(UserId, new Word { EditedBy = new List<string> { UserId } }).Result;
+            Assert.That(word.EditedBy, Has.Count.EqualTo(1));
+        }
+
+        [Test]
+        public void TestCreateMultipleWords()
+        {
+            _ = _wordService.Create(
+                UserId, new List<Word> { new() { ProjectId = ProjId }, new() { ProjectId = ProjId } }).Result;
+            Assert.That(_wordRepo.GetAllWords(ProjId).Result, Has.Count.EqualTo(2));
+            Assert.That(_wordRepo.GetFrontier(ProjId).Result, Has.Count.EqualTo(2));
+        }
+
+        [Test]
+        public void TestUpdateNotInFrontierFalse()
+        {
+            Assert.That(_wordService.Update(ProjId, UserId, WordId, new Word()).Result, Is.False);
+        }
+
+        [Test]
+        public void TestUpdateReplacesFrontierWord()
+        {
+            var word = _wordRepo.AddFrontier(new Word { ProjectId = ProjId }).Result;
+            Assert.That(word, Is.Not.Null);
+            var oldId = word.Id;
+            word.Vernacular = "NewVern";
+            Assert.That(_wordService.Update(ProjId, UserId, oldId, word).Result, Is.True);
+            var frontier = _wordRepo.GetFrontier(ProjId).Result;
+            Assert.That(frontier, Has.Count.EqualTo(1));
+            var newWord = frontier.First();
+            Assert.That(newWord.Id, Is.Not.EqualTo(oldId));
+            Assert.That(newWord.History.Last(), Is.EqualTo(oldId));
+        }
+
+        [Test]
+        public void TestRestoreFrontierWordsMissingWordFalse()
+        {
+            var word = _wordRepo.Add(new Word { ProjectId = ProjId }).Result;
+            Assert.That(_wordService.RestoreFrontierWords(
+                ProjId, new List<string> { "NotAnId", word.Id }).Result, Is.False);
+        }
+
+        [Test]
+        public void TestRestoreFrontierWordsFrontierWordFalse()
+        {
+            var wordNoFrontier = _wordRepo.Add(new Word { ProjectId = ProjId }).Result;
+            var wordYesFrontier = _wordRepo.Create(new Word { ProjectId = ProjId }).Result;
+            Assert.That(_wordRepo.GetFrontier(ProjId).Result, Has.Count.EqualTo(1));
+            Assert.That(_wordService.RestoreFrontierWords(
+                ProjId, new List<string> { wordNoFrontier.Id, wordYesFrontier.Id }).Result, Is.False);
+        }
+
+        [Test]
+        public void TestRestoreFrontierWordsTrue()
+        {
+            var word1 = _wordRepo.Add(new Word { ProjectId = ProjId }).Result;
+            var word2 = _wordRepo.Add(new Word { ProjectId = ProjId }).Result;
+            Assert.That(_wordRepo.GetFrontier(ProjId).Result, Is.Empty);
+            Assert.That(_wordService.RestoreFrontierWords(
+                ProjId, new List<string> { word1.Id, word2.Id }).Result, Is.True);
+            Assert.That(_wordRepo.GetFrontier(ProjId).Result, Has.Count.EqualTo(2));
+        }
+
         [Test]
         public void TestFindContainingWordNoFrontier()
         {
diff --git a/Backend/Controllers/AudioController.cs b/Backend/Controllers/AudioController.cs
index 9a04ed8325..4ccd93df5e 100644
--- a/Backend/Controllers/AudioController.cs
+++ b/Backend/Controllers/AudioController.cs
@@ -74,6 +74,7 @@ public async Task<IActionResult> UploadAudioFile(string projectId, string wordId
             {
                 return Forbid();
             }
+            var userId = _permissionService.GetUserId(HttpContext);
 
             // sanitize user input
             try
@@ -117,7 +118,7 @@ public async Task<IActionResult> UploadAudioFile(string projectId, string wordId
             word.Audio.Add(Path.GetFileName(fileUpload.FilePath));
 
             // Update the word with new audio file
-            await _wordService.Update(projectId, wordId, word);
+            await _wordService.Update(projectId, userId, wordId, word);
 
             return Ok(word.Id);
         }
@@ -131,6 +132,7 @@ public async Task<IActionResult> DeleteAudioFile(string projectId, string wordId
             {
                 return Forbid();
             }
+            var userId = _permissionService.GetUserId(HttpContext);
 
             // sanitize user input
             try
@@ -144,7 +146,7 @@ public async Task<IActionResult> DeleteAudioFile(string projectId, string wordId
                 return new UnsupportedMediaTypeResult();
             }
 
-            var newWord = await _wordService.Delete(projectId, wordId, fileName);
+            var newWord = await _wordService.Delete(projectId, userId, wordId, fileName);
             if (newWord is not null)
             {
                 return Ok(newWord.Id);
diff --git a/Backend/Controllers/MergeController.cs b/Backend/Controllers/MergeController.cs
index 09b46c1468..2abd23d0bc 100644
--- a/Backend/Controllers/MergeController.cs
+++ b/Backend/Controllers/MergeController.cs
@@ -36,10 +36,11 @@ public async Task<IActionResult> MergeWords(
             {
                 return Forbid();
             }
+            var userId = _permissionService.GetUserId(HttpContext);
 
             try
             {
-                var newWords = await _mergeService.Merge(projectId, mergeWordsList);
+                var newWords = await _mergeService.Merge(projectId, userId, mergeWordsList);
                 return Ok(newWords.Select(w => w.Id).ToList());
             }
             catch
@@ -59,8 +60,9 @@ public async Task<IActionResult> UndoMerge(string projectId, [FromBody, BindRequ
             {
                 return Forbid();
             }
+            var userId = _permissionService.GetUserId(HttpContext);
 
-            var undo = await _mergeService.UndoMerge(projectId, merge);
+            var undo = await _mergeService.UndoMerge(projectId, userId, merge);
             return Ok(undo);
         }
 
diff --git a/Backend/Controllers/WordController.cs b/Backend/Controllers/WordController.cs
index 388506dc58..0f6db9917f 100644
--- a/Backend/Controllers/WordController.cs
+++ b/Backend/Controllers/WordController.cs
@@ -28,24 +28,6 @@ public WordController(IWordRepository repo, IWordService wordService, IProjectRe
             _wordService = wordService;
         }
 
-        /// <summary> Deletes all <see cref="Word"/>s for specified <see cref="Project"/>. </summary>
-        /// <returns> true: if success, false: if there were no words </returns>
-        [HttpDelete(Name = "DeleteProjectWords")]
-        [ProducesResponseType(StatusCodes.Status200OK, Type = typeof(bool))]
-        public async Task<IActionResult> DeleteProjectWords(string projectId)
-        {
-            if (!await _permissionService.HasProjectPermission(HttpContext, Permission.Archive, projectId))
-            {
-                return Forbid();
-            }
-            var proj = await _projRepo.GetProject(projectId);
-            if (proj is null)
-            {
-                return NotFound(projectId);
-            }
-            return Ok(await _wordRepo.DeleteAllWords(projectId));
-        }
-
         /// <summary> Deletes specified Frontier <see cref="Word"/>. </summary>
         [HttpDelete("frontier/{wordId}", Name = "DeleteFrontierWord")]
         [ProducesResponseType(StatusCodes.Status200OK, Type = typeof(string))]
@@ -60,7 +42,8 @@ public async Task<IActionResult> DeleteFrontierWord(string projectId, string wor
             {
                 return NotFound(projectId);
             }
-            var id = await _wordService.DeleteFrontierWord(projectId, wordId);
+            var userId = _permissionService.GetUserId(HttpContext);
+            var id = await _wordService.DeleteFrontierWord(projectId, userId, wordId);
             if (id is null)
             {
                 return NotFound(wordId);
@@ -169,7 +152,7 @@ public async Task<IActionResult> GetDuplicateId(string projectId, [FromBody, Bin
         [HttpPost("{dupId}", Name = "UpdateDuplicate")]
         [ProducesResponseType(StatusCodes.Status200OK, Type = typeof(string))]
         public async Task<IActionResult> UpdateDuplicate(
-            string projectId, string dupId, string? userId, [FromBody, BindRequired] Word word)
+            string projectId, string dupId, [FromBody, BindRequired] Word word)
         {
             if (!await _permissionService.HasProjectPermission(HttpContext, Permission.WordEntry, projectId))
             {
@@ -188,16 +171,13 @@ public async Task<IActionResult> UpdateDuplicate(
                 return NotFound(dupId);
             }
 
-            if (string.IsNullOrEmpty(userId))
-            {
-                userId = "";
-            }
+            var userId = _permissionService.GetUserId(HttpContext);
             if (!duplicatedWord.AppendContainedWordContents(word, userId))
             {
                 return Conflict();
             }
 
-            await _wordService.Update(duplicatedWord.ProjectId, duplicatedWord.Id, duplicatedWord);
+            await _wordService.Update(duplicatedWord.ProjectId, userId, duplicatedWord.Id, duplicatedWord);
 
             return Ok(duplicatedWord.Id);
         }
@@ -218,9 +198,8 @@ public async Task<IActionResult> CreateWord(string projectId, [FromBody, BindReq
                 return NotFound(projectId);
             }
             word.ProjectId = projectId;
-
-            await _wordRepo.Create(word);
-            return Ok(word.Id);
+            var userId = _permissionService.GetUserId(HttpContext);
+            return Ok((await _wordService.Create(userId, word)).Id);
         }
 
         /// <summary> Updates a <see cref="Word"/>. </summary>
@@ -247,7 +226,8 @@ public async Task<IActionResult> UpdateWord(
 
             // Add the found id to the updated word.
             word.Id = document.Id;
-            await _wordService.Update(projectId, wordId, word);
+            var userId = _permissionService.GetUserId(HttpContext);
+            await _wordService.Update(projectId, userId, wordId, word);
             return Ok(word.Id);
         }
     }
diff --git a/Backend/Interfaces/IMergeService.cs b/Backend/Interfaces/IMergeService.cs
index 40beae11b5..223a6a91f0 100644
--- a/Backend/Interfaces/IMergeService.cs
+++ b/Backend/Interfaces/IMergeService.cs
@@ -6,8 +6,8 @@ namespace BackendFramework.Interfaces
 {
     public interface IMergeService
     {
-        Task<List<Word>> Merge(string projectId, List<MergeWords> mergeWordsList);
-        Task<bool> UndoMerge(string projectId, MergeUndoIds ids);
+        Task<List<Word>> Merge(string projectId, string userId, List<MergeWords> mergeWordsList);
+        Task<bool> UndoMerge(string projectId, string userId, MergeUndoIds ids);
         Task<MergeWordSet> AddToMergeBlacklist(string projectId, string userId, List<string> wordIds);
         Task<MergeWordSet> AddToMergeGraylist(string projectId, string userId, List<string> wordIds);
         Task<bool> RemoveFromMergeGraylist(string projectId, string userId, List<string> wordIds);
diff --git a/Backend/Interfaces/IWordRepository.cs b/Backend/Interfaces/IWordRepository.cs
index 1f2db182f7..342970e443 100644
--- a/Backend/Interfaces/IWordRepository.cs
+++ b/Backend/Interfaces/IWordRepository.cs
@@ -13,6 +13,7 @@ public interface IWordRepository
         Task<Word> Add(Word word);
         Task<bool> DeleteAllWords(string projectId);
         Task<bool> IsFrontierNonempty(string projectId);
+        Task<bool> IsInFrontier(string projectId, string wordId);
         Task<List<Word>> GetFrontier(string projectId);
         Task<Word> AddFrontier(Word word);
         Task<List<Word>> AddFrontier(List<Word> words);
diff --git a/Backend/Interfaces/IWordService.cs b/Backend/Interfaces/IWordService.cs
index 7df1234dd9..e8b9ddd557 100644
--- a/Backend/Interfaces/IWordService.cs
+++ b/Backend/Interfaces/IWordService.cs
@@ -1,14 +1,18 @@
-using System.Threading.Tasks;
+using System.Collections.Generic;
+using System.Threading.Tasks;
 using BackendFramework.Models;
 
 namespace BackendFramework.Interfaces
 {
     public interface IWordService
     {
-        Task<bool> Update(string projectId, string wordId, Word word);
-        Task<bool> Delete(string projectId, string wordId);
+        Task<Word> Create(string userId, Word word);
+        Task<List<Word>> Create(string userId, List<Word> words);
+        Task<bool> Update(string projectId, string userId, string wordId, Word word);
+        Task<bool> Delete(string projectId, string userId, string wordId);
+        Task<Word?> Delete(string projectId, string userId, string wordId, string fileName);
+        Task<string?> DeleteFrontierWord(string projectId, string userId, string wordId);
+        Task<bool> RestoreFrontierWords(string projectId, List<string> wordIds);
         Task<string?> FindContainingWord(Word word);
-        Task<Word?> Delete(string projectId, string wordId, string fileName);
-        Task<string?> DeleteFrontierWord(string projectId, string wordId);
     }
 }
diff --git a/Backend/Repositories/WordRepository.cs b/Backend/Repositories/WordRepository.cs
index 0423ff8a5d..95259027e4 100644
--- a/Backend/Repositories/WordRepository.cs
+++ b/Backend/Repositories/WordRepository.cs
@@ -131,6 +131,14 @@ public async Task<bool> IsFrontierNonempty(string projectId)
             return word is not null;
         }
 
+        /// <summary> Checks if specified word is in Frontier for specified <see cref="Project"/> </summary>
+        public async Task<bool> IsInFrontier(string projectId, string wordId)
+        {
+            var word = await _wordDatabase.Frontier
+                .Find(w => w.ProjectId == projectId && w.Id == wordId).FirstOrDefaultAsync();
+            return word is not null;
+        }
+
         /// <summary> Finds all <see cref="Word"/>s in the Frontier for specified <see cref="Project"/> </summary>
         public async Task<List<Word>> GetFrontier(string projectId)
         {
@@ -196,22 +204,5 @@ public async Task<bool> UpdateFrontier(Word word)
             }
             return deleted;
         }
-
-        /// <summary> Updates <see cref="Word"/> in the Words collection with same wordId and projectId </summary>
-        /// <returns> A bool: success of operation </returns>
-        private async Task<bool> UpdateWord(Word word)
-        {
-            var filterDef = new FilterDefinitionBuilder<Word>();
-            var filter = filterDef.And(
-                filterDef.Eq(x => x.ProjectId, word.ProjectId),
-                filterDef.Eq(x => x.Id, word.Id));
-
-            var deleted = (await _wordDatabase.Words.DeleteOneAsync(filter)).DeletedCount > 0;
-            if (deleted)
-            {
-                await Add(word);
-            }
-            return deleted;
-        }
     }
 }
diff --git a/Backend/Services/MergeService.cs b/Backend/Services/MergeService.cs
index 01be6ef365..c045745a71 100644
--- a/Backend/Services/MergeService.cs
+++ b/Backend/Services/MergeService.cs
@@ -52,11 +52,6 @@ private async Task<Word> MergePrepParent(string projectId, MergeWords mergeWords
             // Remove duplicates.
             parent.Audio = parent.Audio.Distinct().ToList();
             parent.History = parent.History.Distinct().ToList();
-
-            // Clear fields to be automatically regenerated.
-            parent.Id = "";
-            parent.Modified = "";
-
             return parent;
         }
 
@@ -73,17 +68,17 @@ private async Task<long> MergeDeleteChildren(string projectId, MergeWords mergeW
         /// from the frontier, and adds the new words to the database.
         /// </summary>
         /// <returns> List of new words added. </returns>
-        public async Task<List<Word>> Merge(string projectId, List<MergeWords> mergeWordsList)
+        public async Task<List<Word>> Merge(string projectId, string userId, List<MergeWords> mergeWordsList)
         {
             var keptWords = mergeWordsList.Where(m => !m.DeleteOnly);
             var newWords = keptWords.Select(m => MergePrepParent(projectId, m).Result).ToList();
             await Task.WhenAll(mergeWordsList.Select(m => MergeDeleteChildren(projectId, m)));
-            return await _wordRepo.Create(newWords);
+            return await _wordService.Create(userId, newWords);
         }
 
         /// <summary> Undo merge </summary>
         /// <returns> True if merge was successfully undone </returns>
-        public async Task<bool> UndoMerge(string projectId, MergeUndoIds ids)
+        public async Task<bool> UndoMerge(string projectId, string userId, MergeUndoIds ids)
         {
             foreach (var parentId in ids.ParentIds)
             {
@@ -94,25 +89,15 @@ public async Task<bool> UndoMerge(string projectId, MergeUndoIds ids)
                 }
             }
 
-            var childWords = new List<Word>();
-            foreach (var childId in ids.ChildIds)
+            // If children are not restorable, return without any undo.
+            if (!await _wordService.RestoreFrontierWords(projectId, ids.ChildIds))
             {
-                var childWord = await _wordRepo.GetWord(projectId, childId);
-                if (childWord is null)
-                {
-                    return false;
-                }
-                childWords.Add(childWord);
-            }
-
-
-            // Separate foreach loop for deletion to prevent partial undos
+                return false;
+            };
             foreach (var parentId in ids.ParentIds)
             {
-                await _wordService.DeleteFrontierWord(projectId, parentId);
+                await _wordService.DeleteFrontierWord(projectId, userId, parentId);
             }
-
-            await _wordRepo.AddFrontier(childWords);
             return true;
         }
 
diff --git a/Backend/Services/WordService.cs b/Backend/Services/WordService.cs
index d089a59c6e..15ce094eb3 100644
--- a/Backend/Services/WordService.cs
+++ b/Backend/Services/WordService.cs
@@ -1,4 +1,5 @@
 using System.Collections.Generic;
+using System.Linq;
 using System.Threading.Tasks;
 using BackendFramework.Interfaces;
 using BackendFramework.Models;
@@ -15,9 +16,45 @@ public WordService(IWordRepository wordRepo)
             _wordRepo = wordRepo;
         }
 
+        /// <summary>
+        /// Clear the given word's Id and Metadata to be generated by the word repo,
+        /// and add the given userId to EditedBy if it's not already last on the list.
+        /// </summary>
+        private static Word PrepEditedData(string userId, Word word)
+        {
+            word.Id = "";
+            word.Modified = "";
+            if (!string.IsNullOrWhiteSpace(userId) && userId != word.EditedBy.LastOrDefault(""))
+            {
+                word.EditedBy.Add(userId);
+            }
+            return word;
+        }
+
+        /// <summary> Creates a new word with updated edited data. </summary>
+        /// <returns> The created word </returns>
+        public async Task<Word> Create(string userId, Word word)
+        {
+            return await _wordRepo.Create(PrepEditedData(userId, word));
+        }
+
+        /// <summary> Creates new words with updated edited data. </summary>
+        /// <returns> The created word </returns>
+        public async Task<List<Word>> Create(string userId, List<Word> words)
+        {
+            return await _wordRepo.Create(words.Select(w => PrepEditedData(userId, w)).ToList());
+        }
+
+        /// <summary> Adds a new word with updated edited data. </summary>
+        /// <returns> The added word </returns>
+        private async Task<Word> Add(string userId, Word word)
+        {
+            return await _wordRepo.Add(PrepEditedData(userId, word));
+        }
+
         /// <summary> Makes a new word in Frontier that has deleted tag on each sense </summary>
         /// <returns> A bool: success of operation </returns>
-        public async Task<bool> Delete(string projectId, string wordId)
+        public async Task<bool> Delete(string projectId, string userId, string wordId)
         {
             var wordIsInFrontier = await _wordRepo.DeleteFrontier(projectId, wordId);
 
@@ -33,8 +70,7 @@ public async Task<bool> Delete(string projectId, string wordId)
                 return false;
             }
 
-            wordToDelete.Id = "";
-            wordToDelete.Modified = "";
+            wordToDelete.EditedBy = new List<string>();
             wordToDelete.History = new List<string> { wordId };
             wordToDelete.Accessibility = Status.Deleted;
 
@@ -43,14 +79,14 @@ public async Task<bool> Delete(string projectId, string wordId)
                 senseAcc.Accessibility = Status.Deleted;
             }
 
-            await _wordRepo.Create(wordToDelete);
+            await Create(userId, wordToDelete);
 
             return wordIsInFrontier;
         }
 
-        /// <summary> Removes audio with specified Id from a word </summary>
+        /// <summary> Removes audio with specified fileName from a word </summary>
         /// <returns> New word </returns>
-        public async Task<Word?> Delete(string projectId, string wordId, string fileName)
+        public async Task<Word?> Delete(string projectId, string userId, string wordId, string fileName)
         {
             var wordWithAudioToDelete = await _wordRepo.GetWord(projectId, wordId);
             if (wordWithAudioToDelete is null)
@@ -67,21 +103,14 @@ public async Task<bool> Delete(string projectId, string wordId)
             }
 
             wordWithAudioToDelete.Audio.Remove(fileName);
-            wordWithAudioToDelete.Id = "";
-            wordWithAudioToDelete.Modified = "";
-            wordWithAudioToDelete.ProjectId = projectId;
-
-            // Keep track of the old word, adding it to the history.
             wordWithAudioToDelete.History.Add(wordId);
 
-            wordWithAudioToDelete = await _wordRepo.Create(wordWithAudioToDelete);
-
-            return wordWithAudioToDelete;
+            return await Create(userId, wordWithAudioToDelete);
         }
 
         /// <summary> Deletes word in frontier collection and adds word with deleted tag in word collection </summary>
         /// <returns> A string: id of new word </returns>
-        public async Task<string?> DeleteFrontierWord(string projectId, string wordId)
+        public async Task<string?> DeleteFrontierWord(string projectId, string userId, string wordId)
         {
             var wordIsInFrontier = await _wordRepo.DeleteFrontier(projectId, wordId);
             if (!wordIsInFrontier)
@@ -95,21 +124,34 @@ public async Task<bool> Delete(string projectId, string wordId)
                 return null;
             }
 
-            word.Id = "";
-            word.Modified = "";
             word.ProjectId = projectId;
             word.Accessibility = Status.Deleted;
-
-            // Keep track of the old word, adding it to the history.
             word.History.Add(wordId);
 
-            var deletedWord = await _wordRepo.Add(word);
-            return deletedWord.Id;
+            return (await Add(userId, word)).Id;
+        }
+
+        /// <summary> Restores words to the Frontier </summary>
+        /// <returns> A bool: true if successful, false if any don't exist or are already in the Frontier. </returns>
+        public async Task<bool> RestoreFrontierWords(string projectId, List<string> wordIds)
+        {
+            var words = new List<Word>();
+            foreach (var id in wordIds)
+            {
+                var word = await _wordRepo.GetWord(projectId, id);
+                if (word is null || await _wordRepo.IsInFrontier(projectId, id))
+                {
+                    return false;
+                }
+                words.Add(word);
+            }
+            await _wordRepo.AddFrontier(words);
+            return true;
         }
 
         /// <summary> Makes a new word in the Frontier with changes made </summary>
         /// <returns> A bool: success of operation </returns>
-        public async Task<bool> Update(string projectId, string wordId, Word word)
+        public async Task<bool> Update(string projectId, string userId, string wordId, Word word)
         {
             var wordIsInFrontier = await _wordRepo.DeleteFrontier(projectId, wordId);
 
@@ -119,14 +161,10 @@ public async Task<bool> Update(string projectId, string wordId, Word word)
                 return wordIsInFrontier;
             }
 
-            word.Id = "";
             word.ProjectId = projectId;
-            word.Modified = "";
-
-            // Keep track of the old word, adding it to the history.
             word.History.Add(wordId);
 
-            await _wordRepo.Create(word);
+            await Create(userId, word);
 
             return wordIsInFrontier;
         }
diff --git a/src/api/api/word-api.ts b/src/api/api/word-api.ts
index cf0b8e3a41..ce1bbdedec 100644
--- a/src/api/api/word-api.ts
+++ b/src/api/api/word-api.ts
@@ -150,51 +150,6 @@ export const WordApiAxiosParamCreator = function (
         options: localVarRequestOptions,
       };
     },
-    /**
-     *
-     * @param {string} projectId
-     * @param {*} [options] Override http request option.
-     * @throws {RequiredError}
-     */
-    deleteProjectWords: async (
-      projectId: string,
-      options: any = {}
-    ): Promise<RequestArgs> => {
-      // verify required parameter 'projectId' is not null or undefined
-      assertParamExists("deleteProjectWords", "projectId", projectId);
-      const localVarPath = `/v1/projects/{projectId}/words`.replace(
-        `{${"projectId"}}`,
-        encodeURIComponent(String(projectId))
-      );
-      // use dummy base URL string because the URL constructor only accepts absolute URLs.
-      const localVarUrlObj = new URL(localVarPath, DUMMY_BASE_URL);
-      let baseOptions;
-      if (configuration) {
-        baseOptions = configuration.baseOptions;
-      }
-
-      const localVarRequestOptions = {
-        method: "DELETE",
-        ...baseOptions,
-        ...options,
-      };
-      const localVarHeaderParameter = {} as any;
-      const localVarQueryParameter = {} as any;
-
-      setSearchParams(localVarUrlObj, localVarQueryParameter, options.query);
-      let headersFromBaseOptions =
-        baseOptions && baseOptions.headers ? baseOptions.headers : {};
-      localVarRequestOptions.headers = {
-        ...localVarHeaderParameter,
-        ...headersFromBaseOptions,
-        ...options.headers,
-      };
-
-      return {
-        url: toPathString(localVarUrlObj),
-        options: localVarRequestOptions,
-      };
-    },
     /**
      *
      * @param {string} projectId
@@ -441,7 +396,6 @@ export const WordApiAxiosParamCreator = function (
      * @param {string} projectId
      * @param {string} dupId
      * @param {Word} word
-     * @param {string} [userId]
      * @param {*} [options] Override http request option.
      * @throws {RequiredError}
      */
@@ -449,7 +403,6 @@ export const WordApiAxiosParamCreator = function (
       projectId: string,
       dupId: string,
       word: Word,
-      userId?: string,
       options: any = {}
     ): Promise<RequestArgs> => {
       // verify required parameter 'projectId' is not null or undefined
@@ -476,10 +429,6 @@ export const WordApiAxiosParamCreator = function (
       const localVarHeaderParameter = {} as any;
       const localVarQueryParameter = {} as any;
 
-      if (userId !== undefined) {
-        localVarQueryParameter["userId"] = userId;
-      }
-
       localVarHeaderParameter["Content-Type"] = "application/json";
 
       setSearchParams(localVarUrlObj, localVarQueryParameter, options.query);
@@ -623,27 +572,6 @@ export const WordApiFp = function (configuration?: Configuration) {
         configuration
       );
     },
-    /**
-     *
-     * @param {string} projectId
-     * @param {*} [options] Override http request option.
-     * @throws {RequiredError}
-     */
-    async deleteProjectWords(
-      projectId: string,
-      options?: any
-    ): Promise<
-      (axios?: AxiosInstance, basePath?: string) => AxiosPromise<boolean>
-    > {
-      const localVarAxiosArgs =
-        await localVarAxiosParamCreator.deleteProjectWords(projectId, options);
-      return createRequestFunction(
-        localVarAxiosArgs,
-        globalAxios,
-        BASE_PATH,
-        configuration
-      );
-    },
     /**
      *
      * @param {string} projectId
@@ -769,7 +697,6 @@ export const WordApiFp = function (configuration?: Configuration) {
      * @param {string} projectId
      * @param {string} dupId
      * @param {Word} word
-     * @param {string} [userId]
      * @param {*} [options] Override http request option.
      * @throws {RequiredError}
      */
@@ -777,7 +704,6 @@ export const WordApiFp = function (configuration?: Configuration) {
       projectId: string,
       dupId: string,
       word: Word,
-      userId?: string,
       options?: any
     ): Promise<
       (axios?: AxiosInstance, basePath?: string) => AxiosPromise<string>
@@ -786,7 +712,6 @@ export const WordApiFp = function (configuration?: Configuration) {
         projectId,
         dupId,
         word,
-        userId,
         options
       );
       return createRequestFunction(
@@ -871,20 +796,6 @@ export const WordApiFactory = function (
         .deleteFrontierWord(projectId, wordId, options)
         .then((request) => request(axios, basePath));
     },
-    /**
-     *
-     * @param {string} projectId
-     * @param {*} [options] Override http request option.
-     * @throws {RequiredError}
-     */
-    deleteProjectWords(
-      projectId: string,
-      options?: any
-    ): AxiosPromise<boolean> {
-      return localVarFp
-        .deleteProjectWords(projectId, options)
-        .then((request) => request(axios, basePath));
-    },
     /**
      *
      * @param {string} projectId
@@ -964,7 +875,6 @@ export const WordApiFactory = function (
      * @param {string} projectId
      * @param {string} dupId
      * @param {Word} word
-     * @param {string} [userId]
      * @param {*} [options] Override http request option.
      * @throws {RequiredError}
      */
@@ -972,11 +882,10 @@ export const WordApiFactory = function (
       projectId: string,
       dupId: string,
       word: Word,
-      userId?: string,
       options?: any
     ): AxiosPromise<string> {
       return localVarFp
-        .updateDuplicate(projectId, dupId, word, userId, options)
+        .updateDuplicate(projectId, dupId, word, options)
         .then((request) => request(axios, basePath));
     },
     /**
@@ -1042,20 +951,6 @@ export interface WordApiDeleteFrontierWordRequest {
   readonly wordId: string;
 }
 
-/**
- * Request parameters for deleteProjectWords operation in WordApi.
- * @export
- * @interface WordApiDeleteProjectWordsRequest
- */
-export interface WordApiDeleteProjectWordsRequest {
-  /**
-   *
-   * @type {string}
-   * @memberof WordApiDeleteProjectWords
-   */
-  readonly projectId: string;
-}
-
 /**
  * Request parameters for getDuplicateId operation in WordApi.
  * @export
@@ -1166,13 +1061,6 @@ export interface WordApiUpdateDuplicateRequest {
    * @memberof WordApiUpdateDuplicate
    */
   readonly word: Word;
-
-  /**
-   *
-   * @type {string}
-   * @memberof WordApiUpdateDuplicate
-   */
-  readonly userId?: string;
 }
 
 /**
@@ -1246,22 +1134,6 @@ export class WordApi extends BaseAPI {
       .then((request) => request(this.axios, this.basePath));
   }
 
-  /**
-   *
-   * @param {WordApiDeleteProjectWordsRequest} requestParameters Request parameters.
-   * @param {*} [options] Override http request option.
-   * @throws {RequiredError}
-   * @memberof WordApi
-   */
-  public deleteProjectWords(
-    requestParameters: WordApiDeleteProjectWordsRequest,
-    options?: any
-  ) {
-    return WordApiFp(this.configuration)
-      .deleteProjectWords(requestParameters.projectId, options)
-      .then((request) => request(this.axios, this.basePath));
-  }
-
   /**
    *
    * @param {WordApiGetDuplicateIdRequest} requestParameters Request parameters.
@@ -1359,7 +1231,6 @@ export class WordApi extends BaseAPI {
         requestParameters.projectId,
         requestParameters.dupId,
         requestParameters.word,
-        requestParameters.userId,
         options
       )
       .then((request) => request(this.axios, this.basePath));
diff --git a/src/backend/index.ts b/src/backend/index.ts
index c3266860a5..0ea96fb74a 100644
--- a/src/backend/index.ts
+++ b/src/backend/index.ts
@@ -709,15 +709,9 @@ export async function isFrontierNonempty(projectId?: string): Promise<boolean> {
 
 export async function updateDuplicate(
   dupId: string,
-  userId: string,
   word: Word
 ): Promise<Word> {
-  const params = {
-    projectId: LocalStorage.getProjectId(),
-    dupId,
-    userId,
-    word,
-  };
+  const params = { projectId: LocalStorage.getProjectId(), dupId, word };
   const resp = await wordApi.updateDuplicate(params, defaultOptions());
   return await getWord(resp.data);
 }
diff --git a/src/components/DataEntry/DataEntryTable/index.tsx b/src/components/DataEntry/DataEntryTable/index.tsx
index bfd161daff..5ebc1bc007 100644
--- a/src/components/DataEntry/DataEntryTable/index.tsx
+++ b/src/components/DataEntry/DataEntryTable/index.tsx
@@ -597,7 +597,7 @@ export default function DataEntryTable(
       state.recentWords.findIndex((w) => w.word.id === oldId) > -1;
 
     defunctWord(oldId);
-    const newWord = await backend.updateDuplicate(oldId, getUserId(), word);
+    const newWord = await backend.updateDuplicate(oldId, word);
     defunctWord(oldId, newWord.id);
 
     const newId = await addAudiosToBackend(newWord.id, audioURLs);