diff --git a/server/models/Team.ts b/server/models/Team.ts
index f26248247b60..b09aa1a5d77a 100644
--- a/server/models/Team.ts
+++ b/server/models/Team.ts
@@ -16,6 +16,8 @@ import {
   Is,
   DataType,
   IsUUID,
+  IsUrl,
+  AllowNull,
 } from "sequelize-typescript";
 import { getBaseDomain, RESERVED_SUBDOMAINS } from "@shared/utils/domains";
 import env from "@server/env";
@@ -82,6 +84,8 @@ class Team extends ParanoidModel {
   @Column(DataType.UUID)
   defaultCollectionId: string | null;
 
+  @AllowNull
+  @IsUrl
   @Length({ max: 255, msg: "avatarUrl must be 255 characters or less" })
   @Column
   avatarUrl: string | null;
diff --git a/server/models/User.ts b/server/models/User.ts
index aae09cecb05e..7459dab27db3 100644
--- a/server/models/User.ts
+++ b/server/models/User.ts
@@ -18,6 +18,8 @@ import {
   HasMany,
   Scopes,
   IsDate,
+  IsUrl,
+  AllowNull,
 } from "sequelize-typescript";
 import { languages } from "@shared/i18n";
 import { stringToColor } from "@shared/utils/color";
@@ -154,6 +156,8 @@ class User extends ParanoidModel {
   @Column
   language: string;
 
+  @AllowNull
+  @IsUrl
   @Length({ max: 1000, msg: "avatarUrl must be less than 1000 characters" })
   @Column(DataType.STRING)
   get avatarUrl() {
diff --git a/server/routes/api/attachments.ts b/server/routes/api/attachments.ts
index 8959bf8f6a00..4ae074f19026 100644
--- a/server/routes/api/attachments.ts
+++ b/server/routes/api/attachments.ts
@@ -51,10 +51,11 @@ router.post("attachments.create", auth(), async (ctx) => {
   const acl =
     isPublic === undefined ? AWS_S3_ACL : isPublic ? "public-read" : "private";
   const bucket = acl === "public-read" ? "public" : "uploads";
-  const key = `${bucket}/${user.id}/${s3Key}/${name}`;
+  const keyPrefix = `${bucket}/${user.id}/${s3Key}`;
+  const key = `${keyPrefix}/${name}`;
   const presignedPost = await getPresignedPost(key, acl, contentType);
   const endpoint = publicS3Endpoint();
-  const url = `${endpoint}/${key}`;
+  const url = `${endpoint}/${keyPrefix}/${encodeURIComponent(name)}`;
 
   if (documentId !== undefined) {
     assertUuid(documentId, "documentId must be a uuid");