diff --git a/assets/openapi.json b/assets/openapi.json
index d20ef2fb8..5a81a5de1 100644
Binary files a/assets/openapi.json and b/assets/openapi.json differ
diff --git a/assets/schemas.json b/assets/schemas.json
index bfe3de68c..e092a919f 100644
Binary files a/assets/schemas.json and b/assets/schemas.json differ
diff --git a/src/api/routes/channels/#channel_id/messages/index.ts b/src/api/routes/channels/#channel_id/messages/index.ts
index d399e53af..8790241d8 100644
--- a/src/api/routes/channels/#channel_id/messages/index.ts
+++ b/src/api/routes/channels/#channel_id/messages/index.ts
@@ -18,7 +18,6 @@
 
 import { handleMessage, postHandleMessage, route } from "@spacebar/api";
 import {
-	ApiError,
 	Attachment,
 	AutomodRule,
 	AutomodTriggerTypes,
@@ -39,9 +38,9 @@ import {
 	Relationship,
 	Rights,
 	Snowflake,
+	stringGlobToRegexp,
 	uploadFile,
 	User,
-	stringGlobToRegexp,
 } from "@spacebar/util";
 import { Request, Response, Router } from "express";
 import { HTTPError } from "lambert-server";
@@ -49,6 +48,7 @@ import multer from "multer";
 import { FindManyOptions, FindOperator, LessThan, MoreThan, MoreThanOrEqual } from "typeorm";
 import { URL } from "url";
 import {
+	AcknowledgeDeleteSchema,
 	AutomodCustomWordsRule,
 	AutomodRuleActionType,
 	AutomodRuleEventType,
@@ -57,6 +57,7 @@ import {
 	MessageCreateCloudAttachment,
 	MessageCreateSchema,
 	Reaction,
+	ReadStateType,
 	RelationshipType,
 } from "@spacebar/schemas";
 
@@ -532,4 +533,28 @@ router.post(
 	},
 );
 
+router.delete(
+	"/ack",
+	route({
+		requestBody: "AcknowledgeDeleteSchema",
+		responses: {
+			204: {},
+		},
+	}),
+	async (req: Request, res: Response) => {
+		const { channel_id } = req.params; // not really a channel id if read_state_type != CHANNEL
+		const body = req.body as AcknowledgeDeleteSchema;
+		if (body.version != 2) return res.status(204).send();
+		// TODO: handle other read state types
+		if (body.read_state_type != ReadStateType.CHANNEL) return res.status(204).send();
+
+		const readState = await ReadState.findOne({where: {channel_id}});
+		if (readState) {
+			await readState.remove();
+		}
+
+		res.status(204).send();
+	},
+);
+
 export default router;
diff --git a/src/schemas/uncategorised/MessageAcknowledgeSchema.ts b/src/schemas/uncategorised/MessageAcknowledgeSchema.ts
index 3ba716491..891ccc903 100644
--- a/src/schemas/uncategorised/MessageAcknowledgeSchema.ts
+++ b/src/schemas/uncategorised/MessageAcknowledgeSchema.ts
@@ -19,7 +19,27 @@
 export interface MessageAcknowledgeSchema {
 	manual?: boolean;
 	mention_count?: number;
-	flags?: number;
+	flags?: ReadStateFlags;
 	last_viewed?: number;
 	token?: string;
 }
+
+export interface AcknowledgeDeleteSchema {
+	read_state_type?: ReadStateType;
+	version?: number;
+}
+
+export enum ReadStateType {
+	CHANNEL = 0,
+	GUILD_EVENT = 1,
+	NOTIFICATION_CENTER = 2,
+	GUILD_HOME = 3,
+	GUILD_ONBOARDING_QUESTION = 4,
+	MESSAGE_REQUESTS = 5,
+}
+
+export enum ReadStateFlags {
+	IS_GUILD_CHANNEL = 1 << 0,
+	IS_THREAD = 1 << 1,
+	IS_MENTION_LOW_IMPORTANCE = 1 << 2,
+}
\ No newline at end of file