diff --git a/packages/hydrooj/src/model/contest.ts b/packages/hydrooj/src/model/contest.ts
index b1275d5f6..769755406 100644
--- a/packages/hydrooj/src/model/contest.ts
+++ b/packages/hydrooj/src/model/contest.ts
@@ -12,6 +12,7 @@ import {
     ScoreboardNode, ScoreboardRow, Tdoc,
     Udict,
 } from '../interface';
+import * as bus from '../service/bus';
 import * as misc from '../lib/misc';
 import ranked from '../lib/rank';
 
@@ -402,7 +403,7 @@ function _getStatusJournal(tsdoc) {
     return tsdoc.journal.sort((a, b) => (a.rid.generationTime - b.rid.generationTime));
 }
 
-export function add(
+export async function add(
     domainId: string, title: string, content: string, owner: number,
     rule: string, beginAt = new Date(), endAt = new Date(), pids: ProblemId[] = [],
     rated = false, data: Partial<Tdoc> = {}, type: Type = document.TYPE_CONTEST,
@@ -413,9 +414,12 @@ export function add(
         content, owner, title, rule, beginAt, endAt, pids, attend: 0,
     });
     this.RULES[rule].check(data);
-    return document.add(domainId, content, owner, type, null, null, null, {
+    await bus.serial('contest/before-add', data);
+    const res = await document.add(domainId, content, owner, type, null, null, null, {
         ...data, title, rule, beginAt, endAt, pids, attend: 0, rated,
     });
+    await bus.serial('contest/add', data, res);
+    return res;
 }
 
 export async function edit(
diff --git a/packages/hydrooj/src/service/bus.ts b/packages/hydrooj/src/service/bus.ts
index af32a0233..e204f8d22 100644
--- a/packages/hydrooj/src/service/bus.ts
+++ b/packages/hydrooj/src/service/bus.ts
@@ -2,13 +2,15 @@
 import cluster from 'cluster';
 import serialize from 'serialize-javascript';
 import cac from 'cac';
-import type { Db, FilterQuery, OnlyFieldsOfType } from 'mongodb';
+import type {
+    Db, FilterQuery, ObjectID, OnlyFieldsOfType,
+} from 'mongodb';
 import type { Handler } from './server';
 import { Logger } from '../logger';
 import type {
     MessageDoc, ProblemDoc, RecordDoc,
     TrainingDoc, User, DiscussionDoc,
-    DomainDoc, FileInfo,
+    DomainDoc, FileInfo, Tdoc,
 } from '../interface';
 import type { DocType } from '../model/document';
 import type { ProblemSolutionHandler } from '../handler/problem';
@@ -89,6 +91,9 @@ export interface EventMap extends Record<string, any> {
     'problem/addAdditionalFile': (domainId: string, docId: number, name: string, payload: Omit<FileInfo, '_id'>) => VoidReturn
     'problem/delAdditionalFile': (domainId: string, docId: number, name: string[]) => VoidReturn
 
+    'contest/before-add': (payload: Partial<Tdoc>) => VoidReturn
+    'contest/add': (payload: Partial<Tdoc>, id: ObjectID) => VoidReturn
+
     'training/list': (query: FilterQuery<TrainingDoc>, handler: any) => VoidReturn
     'training/get': (tdoc: TrainingDoc, handler: any) => VoidReturn