diff --git a/src/app/features/collections/components/add-to-collection/project-contributors-step/project-contributors-step.component.ts b/src/app/features/collections/components/add-to-collection/project-contributors-step/project-contributors-step.component.ts
index 35af2dc55..6fcba6f9a 100644
--- a/src/app/features/collections/components/add-to-collection/project-contributors-step/project-contributors-step.component.ts
+++ b/src/app/features/collections/components/add-to-collection/project-contributors-step/project-contributors-step.component.ts
@@ -37,7 +37,6 @@ import { CustomConfirmationService } from '@osf/shared/services/custom-confirmat
 import { CustomDialogService } from '@osf/shared/services/custom-dialog.service';
 import { ToastService } from '@osf/shared/services/toast.service';
 import {
-  AddContributor,
   BulkAddContributors,
   BulkUpdateContributors,
   ContributorsSelectors,
@@ -92,7 +91,6 @@ export class ProjectContributorsStepComponent {
   contributorsSaved = output<void>();
 
   actions = createDispatchMap({
-    addContributor: AddContributor,
     bulkAddContributors: BulkAddContributors,
     bulkUpdateContributors: BulkUpdateContributors,
     deleteContributor: DeleteContributor,
@@ -207,7 +205,7 @@ export class ProjectContributorsStepComponent {
         } else {
           const params = { name: res.data[0].fullName };
 
-          this.actions.addContributor(this.selectedProject()?.id, ResourceType.Project, res.data[0]).subscribe({
+          this.actions.bulkAddContributors(this.selectedProject()?.id, ResourceType.Project, res.data).subscribe({
             next: () => this.toastService.showSuccess('project.contributors.toastMessages.addSuccessMessage', params),
           });
         }
diff --git a/src/app/features/contributors/contributors.component.ts b/src/app/features/contributors/contributors.component.ts
index 8c2ef4b23..118d380f1 100644
--- a/src/app/features/contributors/contributors.component.ts
+++ b/src/app/features/contributors/contributors.component.ts
@@ -45,7 +45,6 @@ import { LoaderService } from '@osf/shared/services/loader.service';
 import { ToastService } from '@osf/shared/services/toast.service';
 import {
   AcceptRequestAccess,
-  AddContributor,
   BulkAddContributors,
   BulkAddContributorsFromParentProject,
   BulkUpdateContributors,
@@ -176,7 +175,6 @@ export class ContributorsComponent implements OnInit, OnDestroy {
     bulkUpdateContributors: BulkUpdateContributors,
     bulkAddContributors: BulkAddContributors,
     bulkAddContributorsFromParentProject: BulkAddContributorsFromParentProject,
-    addContributor: AddContributor,
     createViewOnlyLink: CreateViewOnlyLink,
     deleteViewOnlyLink: DeleteViewOnlyLink,
     getRequestAccessContributors: GetRequestAccessContributors,
@@ -327,7 +325,7 @@ export class ContributorsComponent implements OnInit, OnDestroy {
 
   private addContributorsToComponents(result: ContributorDialogAddModel): void {
     this.actions
-      .bulkAddContributors(this.resourceId(), this.resourceType(), result.data, result.childNodeIds)
+      .bulkAddContributors(this.resourceId(), this.resourceType(), result.data)
       .pipe(takeUntilDestroyed(this.destroyRef))
       .subscribe(() => this.toastService.showSuccess('project.contributors.toastMessages.multipleAddSuccessMessage'));
   }
@@ -355,7 +353,7 @@ export class ContributorsComponent implements OnInit, OnDestroy {
         } else {
           const params = { name: res.data[0].fullName };
 
-          this.actions.addContributor(this.resourceId(), this.resourceType(), res.data[0]).subscribe({
+          this.actions.bulkAddContributors(this.resourceId(), this.resourceType(), res.data).subscribe({
             next: () => this.toastService.showSuccess('project.contributors.toastMessages.addSuccessMessage', params),
           });
         }
diff --git a/src/app/features/metadata/dialogs/contributors-dialog/contributors-dialog.component.ts b/src/app/features/metadata/dialogs/contributors-dialog/contributors-dialog.component.ts
index 896cbae48..f9a6d0b3d 100644
--- a/src/app/features/metadata/dialogs/contributors-dialog/contributors-dialog.component.ts
+++ b/src/app/features/metadata/dialogs/contributors-dialog/contributors-dialog.component.ts
@@ -36,7 +36,6 @@ import { CustomConfirmationService } from '@osf/shared/services/custom-confirmat
 import { CustomDialogService } from '@osf/shared/services/custom-dialog.service';
 import { ToastService } from '@osf/shared/services/toast.service';
 import {
-  AddContributor,
   BulkAddContributors,
   BulkUpdateContributors,
   ContributorsSelectors,
@@ -96,7 +95,6 @@ export class ContributorsDialogComponent implements OnInit {
     updatePermissionFilter: UpdatePermissionFilter,
     updateBibliographyFilter: UpdateBibliographyFilter,
     deleteContributor: DeleteContributor,
-    addContributor: AddContributor,
     bulkAddContributors: BulkAddContributors,
     bulkUpdateContributors: BulkUpdateContributors,
     loadMoreContributors: LoadMoreContributors,
@@ -178,7 +176,7 @@ export class ContributorsDialogComponent implements OnInit {
         } else {
           const params = { name: res.data[0].fullName };
 
-          this.actions.addContributor(this.resourceId, this.resourceType, res.data[0]).subscribe({
+          this.actions.bulkAddContributors(this.resourceId, this.resourceType, res.data).subscribe({
             next: () => {
               this.changesMade.set(true);
               this.toastService.showSuccess('project.contributors.toastMessages.addSuccessMessage', params);
diff --git a/src/app/features/preprints/components/stepper/preprints-metadata-step/preprints-contributors/preprints-contributors.component.ts b/src/app/features/preprints/components/stepper/preprints-metadata-step/preprints-contributors/preprints-contributors.component.ts
index e54f8787d..3fbfa30d6 100644
--- a/src/app/features/preprints/components/stepper/preprints-metadata-step/preprints-contributors/preprints-contributors.component.ts
+++ b/src/app/features/preprints/components/stepper/preprints-metadata-step/preprints-contributors/preprints-contributors.component.ts
@@ -36,7 +36,6 @@ import { CustomConfirmationService } from '@osf/shared/services/custom-confirmat
 import { CustomDialogService } from '@osf/shared/services/custom-dialog.service';
 import { ToastService } from '@osf/shared/services/toast.service';
 import {
-  AddContributor,
   BulkAddContributors,
   BulkUpdateContributors,
   ContributorsSelectors,
@@ -84,7 +83,6 @@ export class PreprintsContributorsComponent implements OnInit {
     deleteContributor: DeleteContributor,
     bulkUpdateContributors: BulkUpdateContributors,
     bulkAddContributors: BulkAddContributors,
-    addContributor: AddContributor,
     loadMoreContributors: LoadMoreContributors,
   });
 
@@ -157,7 +155,7 @@ export class PreprintsContributorsComponent implements OnInit {
         } else {
           const params = { name: res.data[0].fullName };
 
-          this.actions.addContributor(this.preprintId(), ResourceType.Preprint, res.data[0]).subscribe({
+          this.actions.bulkAddContributors(this.preprintId(), ResourceType.Preprint, res.data).subscribe({
             next: () => this.toastService.showSuccess('project.contributors.toastMessages.addSuccessMessage', params),
           });
         }
diff --git a/src/app/features/registries/components/registries-metadata-step/registries-contributors/registries-contributors.component.ts b/src/app/features/registries/components/registries-metadata-step/registries-contributors/registries-contributors.component.ts
index 9423f6a95..c69bc4e41 100644
--- a/src/app/features/registries/components/registries-metadata-step/registries-contributors/registries-contributors.component.ts
+++ b/src/app/features/registries/components/registries-metadata-step/registries-contributors/registries-contributors.component.ts
@@ -37,7 +37,6 @@ import { CustomConfirmationService } from '@osf/shared/services/custom-confirmat
 import { CustomDialogService } from '@osf/shared/services/custom-dialog.service';
 import { ToastService } from '@osf/shared/services/toast.service';
 import {
-  AddContributor,
   BulkAddContributors,
   BulkUpdateContributors,
   ContributorsSelectors,
@@ -90,7 +89,6 @@ export class RegistriesContributorsComponent implements OnInit, OnDestroy {
     deleteContributor: DeleteContributor,
     bulkUpdateContributors: BulkUpdateContributors,
     bulkAddContributors: BulkAddContributors,
-    addContributor: AddContributor,
     loadMoreContributors: LoadMoreContributors,
     resetContributorsState: ResetContributorsState,
   });
@@ -176,7 +174,7 @@ export class RegistriesContributorsComponent implements OnInit, OnDestroy {
         } else {
           const params = { name: res.data[0].fullName };
 
-          this.actions.addContributor(this.draftId(), ResourceType.DraftRegistration, res.data[0]).subscribe({
+          this.actions.bulkAddContributors(this.draftId(), ResourceType.DraftRegistration, res.data).subscribe({
             next: () => this.toastService.showSuccess('project.contributors.toastMessages.addSuccessMessage', params),
           });
         }
diff --git a/src/app/shared/components/contributors/add-contributor-dialog/add-contributor-dialog.component.ts b/src/app/shared/components/contributors/add-contributor-dialog/add-contributor-dialog.component.ts
index fd4d1dd00..dd6c908a5 100644
--- a/src/app/shared/components/contributors/add-contributor-dialog/add-contributor-dialog.component.ts
+++ b/src/app/shared/components/contributors/add-contributor-dialog/add-contributor-dialog.component.ts
@@ -85,8 +85,12 @@ export class AddContributorDialogComponent implements OnInit, OnDestroy {
   readonly isSearchState = computed(() => this.currentState() === AddDialogState.Search);
   readonly isDetailsState = computed(() => this.currentState() === AddDialogState.Details);
   readonly isComponentsState = computed(() => this.currentState() === AddDialogState.Components);
-  readonly hasComponents = computed(() => this.components().length > 0);
-  readonly buttonLabel = computed(() => (this.isComponentsState() ? 'common.buttons.done' : 'common.buttons.next'));
+  readonly hasComponents = computed(() => this.components().length > 1);
+  readonly buttonLabel = computed(() =>
+    (this.isDetailsState() && !this.hasComponents()) || this.isComponentsState()
+      ? 'common.buttons.done'
+      : 'common.buttons.next'
+  );
 
   constructor() {
     this.setupEffects();
diff --git a/src/app/shared/mappers/contributors/contributors.mapper.ts b/src/app/shared/mappers/contributors/contributors.mapper.ts
index b0546f98e..97f400f7d 100644
--- a/src/app/shared/mappers/contributors/contributors.mapper.ts
+++ b/src/app/shared/mappers/contributors/contributors.mapper.ts
@@ -110,4 +110,25 @@ export class ContributorsMapper {
       };
     }
   }
+
+  static toContributorUpdateRequest(model: ContributorModel): ContributorAddRequestModel {
+    return {
+      id: model.id,
+      type: 'contributors',
+      attributes: {
+        bibliographic: model.isBibliographic,
+        permission: model.permission,
+        index: model.index,
+        id: model.userId,
+      },
+      relationships: {
+        users: {
+          data: {
+            id: model.id,
+            type: 'users',
+          },
+        },
+      },
+    };
+  }
 }
diff --git a/src/app/shared/models/contributors/contributor-response-json-api.model.ts b/src/app/shared/models/contributors/contributor-response-json-api.model.ts
index 295d8608c..72f5fc024 100644
--- a/src/app/shared/models/contributors/contributor-response-json-api.model.ts
+++ b/src/app/shared/models/contributors/contributor-response-json-api.model.ts
@@ -33,6 +33,7 @@ export interface ContributorEmbedsJsonApi {
 
 export interface ContributorAddRequestModel {
   type: 'contributors';
+  id?: string;
   attributes: {
     bibliographic: boolean;
     permission: string;
diff --git a/src/app/shared/services/contributors.service.ts b/src/app/shared/services/contributors.service.ts
index c441b9ca0..df2af3cf0 100644
--- a/src/app/shared/services/contributors.service.ts
+++ b/src/app/shared/services/contributors.service.ts
@@ -1,4 +1,4 @@
-import { forkJoin, map, Observable, of } from 'rxjs';
+import { map, Observable, of } from 'rxjs';
 
 import { inject, Injectable } from '@angular/core';
 
@@ -10,11 +10,7 @@ import { ContributorsMapper } from '../mappers/contributors';
 import { ResponseJsonApi } from '../models/common/json-api.model';
 import { ContributorModel } from '../models/contributors/contributor.model';
 import { ContributorAddModel } from '../models/contributors/contributor-add.model';
-import {
-  ContributorDataJsonApi,
-  ContributorResponseJsonApi,
-  ContributorsResponseJsonApi,
-} from '../models/contributors/contributor-response-json-api.model';
+import { ContributorsResponseJsonApi } from '../models/contributors/contributor-response-json-api.model';
 import { PaginatedData } from '../models/paginated-data.model';
 import { UserDataJsonApi } from '../models/user/user-json-api.model';
 
@@ -110,25 +106,19 @@ export class ContributorsService {
       return of([]);
     }
 
-    const updateRequests = contributors.map((contributor) =>
-      this.updateContributor(resourceType, resourceId, contributor)
-    );
-
-    return forkJoin(updateRequests);
-  }
+    const baseUrl = `${this.getBaseUrl(resourceType, resourceId)}/`;
 
-  updateContributor(
-    resourceType: ResourceType,
-    resourceId: string,
-    data: ContributorModel
-  ): Observable<ContributorModel> {
-    const baseUrl = `${this.getBaseUrl(resourceType, resourceId)}/${data.userId}/`;
+    const contributorData = {
+      data: contributors.map((contributor) => ContributorsMapper.toContributorUpdateRequest(contributor)),
+    };
 
-    const contributorData = { data: ContributorsMapper.toContributorAddRequest(data) };
+    const headers = {
+      'Content-Type': 'application/vnd.api+json; ext=bulk',
+    };
 
     return this.jsonApiService
-      .patch<ContributorDataJsonApi>(baseUrl, contributorData)
-      .pipe(map((contributor) => ContributorsMapper.getContributor(contributor)));
+      .patch<ContributorsResponseJsonApi>(baseUrl, contributorData, undefined, headers)
+      .pipe(map((response) => ContributorsMapper.getContributors(response.data)));
   }
 
   bulkAddContributors(
@@ -141,27 +131,22 @@ export class ContributorsService {
       return of([]);
     }
 
-    const addRequests = contributors.map((contributor) =>
-      this.addContributor(resourceType, resourceId, contributor, childNodeIds)
-    );
-
-    return forkJoin(addRequests);
-  }
-
-  addContributor(
-    resourceType: ResourceType,
-    resourceId: string,
-    data: ContributorAddModel,
-    childNodeIds?: string[]
-  ): Observable<ContributorModel> {
     const baseUrl = `${this.getBaseUrl(resourceType, resourceId)}/`;
-    const type = data.id ? AddContributorType.Registered : AddContributorType.Unregistered;
 
-    const contributorData = { data: ContributorsMapper.toContributorAddRequest(data, type, childNodeIds) };
+    const contributorData = {
+      data: contributors.map((contributor) => {
+        const type = contributor.id ? AddContributorType.Registered : AddContributorType.Unregistered;
+        return ContributorsMapper.toContributorAddRequest(contributor, type, childNodeIds);
+      }),
+    };
+
+    const headers = {
+      'Content-Type': 'application/vnd.api+json; ext=bulk',
+    };
 
     return this.jsonApiService
-      .post<ContributorResponseJsonApi>(baseUrl, contributorData)
-      .pipe(map((contributor) => ContributorsMapper.getContributor(contributor.data)));
+      .post<ContributorsResponseJsonApi>(baseUrl, contributorData, undefined, headers)
+      .pipe(map((response) => ContributorsMapper.getContributors(response.data)));
   }
 
   addContributorsFromProject(resourceType: ResourceType, resourceId: string): Observable<void> {
diff --git a/src/app/shared/services/json-api.service.ts b/src/app/shared/services/json-api.service.ts
index 28fe82f87..09865805c 100644
--- a/src/app/shared/services/json-api.service.ts
+++ b/src/app/shared/services/json-api.service.ts
@@ -35,8 +35,13 @@ export class JsonApiService {
     return httpParams;
   }
 
-  post<T>(url: string, body?: unknown, params?: Record<string, unknown>): Observable<T> {
-    return this.http.post<T>(url, body, { params: this.buildHttpParams(params) });
+  post<T>(
+    url: string,
+    body?: unknown,
+    params?: Record<string, unknown>,
+    headers?: Record<string, string>
+  ): Observable<T> {
+    return this.http.post<T>(url, body, { params: this.buildHttpParams(params), headers });
   }
 
   patch<T>(
diff --git a/src/app/shared/stores/contributors/contributors.actions.ts b/src/app/shared/stores/contributors/contributors.actions.ts
index 2bb634cfc..470948c3a 100644
--- a/src/app/shared/stores/contributors/contributors.actions.ts
+++ b/src/app/shared/stores/contributors/contributors.actions.ts
@@ -33,16 +33,6 @@ export class UpdateBibliographyFilter {
   constructor(public bibliographyFilter: boolean | null) {}
 }
 
-export class AddContributor {
-  static readonly type = '[Contributors] Add Contributor';
-
-  constructor(
-    public resourceId: string | undefined | null,
-    public resourceType: ResourceType | undefined,
-    public contributor: ContributorAddModel
-  ) {}
-}
-
 export class BulkUpdateContributors {
   static readonly type = '[Contributors] Bulk Update Contributors';
 
diff --git a/src/app/shared/stores/contributors/contributors.state.ts b/src/app/shared/stores/contributors/contributors.state.ts
index 0e738afec..768983661 100644
--- a/src/app/shared/stores/contributors/contributors.state.ts
+++ b/src/app/shared/stores/contributors/contributors.state.ts
@@ -10,7 +10,6 @@ import { RequestAccessService } from '@osf/shared/services/request-access.servic
 
 import {
   AcceptRequestAccess,
-  AddContributor,
   BulkAddContributors,
   BulkAddContributorsFromParentProject,
   BulkUpdateContributors,
@@ -145,28 +144,6 @@ export class ContributorsState {
     );
   }
 
-  @Action(AddContributor)
-  addContributor(ctx: StateContext<ContributorsStateModel>, action: AddContributor) {
-    const state = ctx.getState();
-
-    if (!action.resourceId || !action.resourceType) {
-      return;
-    }
-
-    ctx.patchState({
-      contributorsList: { ...state.contributorsList, isLoading: true, error: null },
-    });
-
-    return this.contributorsService.addContributor(action.resourceType, action.resourceId, action.contributor).pipe(
-      tap(() => {
-        ctx.dispatch(
-          new GetAllContributors(action.resourceId, action.resourceType, 1, state.contributorsList.pageSize)
-        );
-      }),
-      catchError((error) => handleSectionError(ctx, 'contributorsList', error))
-    );
-  }
-
   @Action(BulkUpdateContributors)
   bulkUpdateContributors(ctx: StateContext<ContributorsStateModel>, action: BulkUpdateContributors) {
     const state = ctx.getState();
@@ -204,7 +181,7 @@ export class ContributorsState {
     });
 
     return this.contributorsService
-      .bulkAddContributors(action.resourceType, action.resourceId, action.contributors, action.childNodeIds)
+      .bulkAddContributors(action.resourceType, action.resourceId, action.contributors)
       .pipe(
         tap(() => {
           ctx.dispatch(