diff --git a/apps/relayer/package.json b/apps/relayer/package.json
index 649a03e07..b5aa86a57 100644
--- a/apps/relayer/package.json
+++ b/apps/relayer/package.json
@@ -41,6 +41,7 @@
     "hardhat": "^2.22.15",
     "helmet": "^8.0.0",
     "maci-contracts": "workspace:^2.5.0",
+    "maci-domainobjs": "workspace:^2.5.0",
     "mustache": "^4.2.0",
     "reflect-metadata": "^0.2.0",
     "rxjs": "^7.8.1",
diff --git a/apps/relayer/tests/messages.test.ts b/apps/relayer/tests/messages.test.ts
new file mode 100644
index 000000000..72d59ac63
--- /dev/null
+++ b/apps/relayer/tests/messages.test.ts
@@ -0,0 +1,89 @@
+import { HttpStatus, ValidationPipe, type INestApplication } from "@nestjs/common";
+import { Test } from "@nestjs/testing";
+import { ZeroAddress } from "ethers";
+import { Keypair } from "maci-domainobjs";
+import request from "supertest";
+
+import type { App } from "supertest/types";
+
+import { AppModule } from "../ts/app.module";
+
+describe("e2e messages", () => {
+  let app: INestApplication;
+
+  beforeAll(async () => {
+    const moduleFixture = await Test.createTestingModule({
+      imports: [AppModule],
+    }).compile();
+
+    app = moduleFixture.createNestApplication();
+    app.useGlobalPipes(new ValidationPipe({ transform: true }));
+    await app.listen(3001);
+  });
+
+  afterAll(async () => {
+    await app.close();
+  });
+
+  describe("/v1/messages/publish", () => {
+    const keypair = new Keypair();
+
+    const defaultSaveMessagesArgs = {
+      maciContractAddress: ZeroAddress,
+      poll: 0,
+      messages: [
+        {
+          data: ["0", "1", "2", "3", "4", "5", "6", "7", "8", "9"],
+          publicKey: keypair.pubKey.serialize(),
+        },
+      ],
+    };
+
+    test("should throw an error if dto is invalid", async () => {
+      const result = await request(app.getHttpServer() as App)
+        .post("/v1/messages/publish")
+        .send({
+          maciContractAddress: "invalid",
+          poll: "-1",
+          messages: [],
+        })
+        .expect(HttpStatus.BAD_REQUEST);
+
+      expect(result.body).toStrictEqual({
+        error: "Bad Request",
+        statusCode: HttpStatus.BAD_REQUEST,
+        message: [
+          "poll must not be less than 0",
+          "poll must be an integer number",
+          "maciContractAddress must be an Ethereum address",
+          "messages must contain at least 1 elements",
+        ],
+      });
+    });
+
+    test("should throw an error if messages dto is invalid", async () => {
+      const result = await request(app.getHttpServer() as App)
+        .post("/v1/messages/publish")
+        .send({
+          ...defaultSaveMessagesArgs,
+          messages: [{ data: [], publicKey: "invalid" }],
+        })
+        .expect(HttpStatus.BAD_REQUEST);
+
+      expect(result.body).toStrictEqual({
+        error: "Bad Request",
+        statusCode: HttpStatus.BAD_REQUEST,
+        message: ["messages.0.data must contain at least 10 elements", "messages.0.Public key (invalid) is invalid"],
+      });
+    });
+
+    test("should publish user messages properly", async () => {
+      const result = await request(app.getHttpServer() as App)
+        .post("/v1/messages/publish")
+        .send(defaultSaveMessagesArgs)
+        .expect(HttpStatus.CREATED);
+
+      expect(result.status).toBe(HttpStatus.CREATED);
+    });
+  });
+});
diff --git a/apps/relayer/ts/app.module.ts b/apps/relayer/ts/app.module.ts
index b1a904677..fdc8e1fa6 100644
--- a/apps/relayer/ts/app.module.ts
+++ b/apps/relayer/ts/app.module.ts
@@ -1,6 +1,8 @@
 import { Module } from "@nestjs/common";
 import { ThrottlerModule } from "@nestjs/throttler";
 
+import { MessageModule } from "./message/message.module";
+
 @Module({
   imports: [
     ThrottlerModule.forRoot([
@@ -9,6 +11,7 @@ import { ThrottlerModule } from "@nestjs/throttler";
         limit: Number(process.env.LIMIT),
       },
     ]),
+    MessageModule,
   ],
 })
 export class AppModule {}
diff --git a/apps/relayer/ts/message/__tests__/message.controller.test.ts b/apps/relayer/ts/message/__tests__/message.controller.test.ts
new file mode 100644
index 000000000..2451685a8
--- /dev/null
+++ b/apps/relayer/ts/message/__tests__/message.controller.test.ts
@@ -0,0 +1,55 @@
+import { HttpException, HttpStatus } from "@nestjs/common";
+import { Test } from "@nestjs/testing";
+
+import { MessageController } from "../message.controller";
+import { MessageService } from "../message.service";
+
+import { defaultSaveMessagesArgs } from "./utils";
+
+describe("MessageController", () => {
+  let controller: MessageController;
+
+  const mockMessageService = {
+    saveMessages: jest.fn(),
+    merge: jest.fn(),
+  };
+
+  beforeEach(async () => {
+    const app = await Test.createTestingModule({
+      controllers: [MessageController],
+    })
+      .useMocker((token) => {
+        if (token === MessageService) {
+          mockMessageService.saveMessages.mockResolvedValue(true);
+
+          return mockMessageService;
+        }
+
+        return jest.fn();
+      })
+      .compile();
+
+    controller = app.get<MessageController>(MessageController);
+  });
+
+  afterEach(() => {
+    jest.clearAllMocks();
+  });
+
+  describe("v1/messages/publish", () => {
+    test("should publish user messages properly", async () => {
+      const data = await controller.publish(defaultSaveMessagesArgs);
+
+      expect(data).toBe(true);
+    });
+
+    test("should throw an error if messages saving is failed", async () => {
+      const error = new Error("error");
+      mockMessageService.saveMessages.mockRejectedValue(error);
+
+      await expect(controller.publish(defaultSaveMessagesArgs)).rejects.toThrow(
+        new HttpException(error.message, HttpStatus.BAD_REQUEST),
+      );
+    });
+  });
+});
diff --git a/apps/relayer/ts/message/__tests__/message.service.test.ts b/apps/relayer/ts/message/__tests__/message.service.test.ts
new file mode 100644
index 000000000..114b8d326
--- /dev/null
+++ b/apps/relayer/ts/message/__tests__/message.service.test.ts
@@ -0,0 +1,21 @@
+import { MessageService } from "../message.service";
+
+import { defaultSaveMessagesArgs } from "./utils";
+
+describe("MessageService", () => {
+  test("should save messages properly", async () => {
+    const service = new MessageService();
+
+    const result = await service.saveMessages(defaultSaveMessagesArgs);
+
+    expect(result).toBe(true);
+  });
+
+  test("should publish messages properly", async () => {
+    const service = new MessageService();
+
+    const result = await service.publishMessages(defaultSaveMessagesArgs);
+
+    expect(result).toStrictEqual({ hash: "", ipfsHash: "" });
+  });
+});
diff --git a/apps/relayer/ts/message/__tests__/utils.ts b/apps/relayer/ts/message/__tests__/utils.ts
new file mode 100644
index 000000000..3852210ea
--- /dev/null
+++ b/apps/relayer/ts/message/__tests__/utils.ts
@@ -0,0 +1,15 @@
+import { ZeroAddress } from "ethers";
+import { Keypair } from "maci-domainobjs";
+
+const keypair = new Keypair();
+
+export const defaultSaveMessagesArgs = {
+  maciContractAddress: ZeroAddress,
+  poll: 0,
+  messages: [
+    {
+      data: ["0", "1", "2", "3", "4", "5", "6", "7", "8", "9"],
+      publicKey: keypair.pubKey.serialize(),
+    },
+  ],
+};
diff --git a/apps/relayer/ts/message/__tests__/validation.test.ts b/apps/relayer/ts/message/__tests__/validation.test.ts
new file mode 100644
index 000000000..fe7e72671
--- /dev/null
+++ b/apps/relayer/ts/message/__tests__/validation.test.ts
@@ -0,0 +1,30 @@
+import { Keypair } from "maci-domainobjs";
+
+import { PublicKeyValidator } from "../validation";
+
+describe("PublicKeyValidator", () => {
+  test("should validate valid public key", () => {
+    const keypair = new Keypair();
+    const validator = new PublicKeyValidator();
+
+    const result = validator.validate(keypair.pubKey.serialize());
+
+    expect(result).toBe(true);
+  });
+
+  test("should validate invalid public key", () => {
+    const validator = new PublicKeyValidator();
+
+    const result = validator.validate("invalid");
+
+    expect(result).toBe(false);
+  });
+
+  test("should return default message properly", () => {
+    const validator = new PublicKeyValidator();
+
+    const result = validator.defaultMessage();
+
+    expect(result).toBe("Public key ($value) is invalid");
+  });
+});
diff --git a/apps/relayer/ts/message/dto.ts b/apps/relayer/ts/message/dto.ts
new file mode 100644
index 000000000..a5e25e701
--- /dev/null
+++ b/apps/relayer/ts/message/dto.ts
@@ -0,0 +1,88 @@
+import { ApiProperty } from "@nestjs/swagger";
+import { Type } from "class-transformer";
+import {
+  IsEthereumAddress,
+  IsInt,
+  Min,
+  Validate,
+  IsArray,
+  ArrayMinSize,
+  ArrayMaxSize,
+  ValidateNested,
+} from "class-validator";
+import { Message } from "maci-domainobjs";
+
+import { PublicKeyValidator } from "./validation";
+
+/**
+ * Max messages per batch
+ */
+const MAX_MESSAGES = 20;
+
+/**
+ * Data transfer object for user message
+ */
+export class MessageContractParamsDto {
+  /**
+   * Message data
+   */
+  @ApiProperty({
+    description: "Message data",
+    type: [String],
+  })
+  @IsArray()
+  @ArrayMinSize(Message.DATA_LENGTH)
+  @ArrayMaxSize(Message.DATA_LENGTH)
+  data!: string[];
+
+  /**
+   * Public key
+   */
+  @ApiProperty({
+    description: "Public key",
+    type: String,
+  })
+  @Validate(PublicKeyValidator)
+  publicKey!: string;
+}
+
+/**
+ * Data transfer object for publish messages
+ */
+export class PublishMessagesDto {
+  /**
+   * Poll id
+   */
+  @ApiProperty({
+    description: "Poll id",
+    minimum: 0,
+    type: Number,
+  })
+  @IsInt()
+  @Min(0)
+  poll!: number;
+
+  /**
+   * Maci contract address
+   */
+  @ApiProperty({
+    description: "MACI contract address",
+    type: String,
+  })
+  @IsEthereumAddress()
+  maciContractAddress!: string;
+
+  /**
+   * Messages
+   */
+  @ApiProperty({
+    description: "User messages with public key",
+    type: [MessageContractParamsDto],
+  })
+  @IsArray()
+  @ArrayMinSize(1)
+  @ArrayMaxSize(MAX_MESSAGES)
+  @ValidateNested({ each: true })
+  @Type(() => MessageContractParamsDto)
+  messages!: MessageContractParamsDto[];
+}
diff --git a/apps/relayer/ts/message/message.controller.ts b/apps/relayer/ts/message/message.controller.ts
new file mode 100644
index 000000000..1f2da30dc
--- /dev/null
+++ b/apps/relayer/ts/message/message.controller.ts
@@ -0,0 +1,41 @@
+/* eslint-disable @typescript-eslint/no-shadow */
+import { Body, Controller, HttpException, HttpStatus, Logger, Post } from "@nestjs/common";
+import { ApiBearerAuth, ApiBody, ApiResponse, ApiTags } from "@nestjs/swagger";
+
+import { PublishMessagesDto } from "./dto";
+import { MessageService } from "./message.service";
+
+@ApiTags("v1/messages")
+@ApiBearerAuth()
+@Controller("v1/messages")
+export class MessageController {
+  /**
+   * Logger
+   */
+  private readonly logger = new Logger(MessageController.name);
+
+  /**
+   * Initialize MessageController
+   *
+   */
+  constructor(private readonly messageService: MessageService) {}
+
+  /**
+   * Publish user messages api method.
+   * Saves messages batch and then send them onchain by calling `publishMessages` method via cron job.
+   *
+   * @param args - publish messages dto
+   * @returns success or not
+   */
+  @ApiBody({ type: PublishMessagesDto })
+  @ApiResponse({ status: HttpStatus.CREATED, description: "The messages have been successfully accepted" })
+  @ApiResponse({ status: HttpStatus.FORBIDDEN, description: "Forbidden" })
+  @ApiResponse({ status: HttpStatus.BAD_REQUEST, description: "BadRequest" })
+  @Post("publish")
+  async publish(@Body() args: PublishMessagesDto): Promise<boolean> {
+    return this.messageService.saveMessages(args).catch((error: Error) => {
+      this.logger.error(`Error:`, error);
+      throw new HttpException(error.message, HttpStatus.BAD_REQUEST);
+    });
+  }
+}
diff --git a/apps/relayer/ts/message/message.module.ts b/apps/relayer/ts/message/message.module.ts
new file mode 100644
index 000000000..d24abda23
--- /dev/null
+++ b/apps/relayer/ts/message/message.module.ts
@@ -0,0 +1,10 @@
+import { Module } from "@nestjs/common";
+
+import { MessageController } from "./message.controller";
+import { MessageService } from "./message.service";
+
+@Module({
+  controllers: [MessageController],
+  providers: [MessageService],
+})
+export class MessageModule {}
diff --git a/apps/relayer/ts/message/message.service.ts b/apps/relayer/ts/message/message.service.ts
new file mode 100644
index 000000000..c554f6a62
--- /dev/null
+++ b/apps/relayer/ts/message/message.service.ts
@@ -0,0 +1,37 @@
+import { Injectable, Logger } from "@nestjs/common";
+
+import type { PublishMessagesDto } from "./dto";
+import type { IPublishMessagesReturn } from "./types";
+
+/**
+ * MessageService is responsible for saving message batches and send them onchain
+ */
+@Injectable()
+export class MessageService {
+  /**
+   * Logger
+   */
+  private readonly logger: Logger = new Logger(MessageService.name);
+
+  /**
+   * Save messages batch
+   *
+   * @param args - publish messages dto
+   * @returns success or not
+   */
+  async saveMessages(args: PublishMessagesDto): Promise<boolean> {
+    this.logger.log("Save messages", args);
+    return Promise.resolve(true);
+  }
+
+  /**
+   * Publish messages onchain
+   *
+   * @param args - publish messages dto
+   * @returns transaction and ipfs hashes
+   */
+  async publishMessages(args: PublishMessagesDto): Promise<IPublishMessagesReturn> {
+    this.logger.log("Publish messages", args);
+    return Promise.resolve({ hash: "", ipfsHash: "" });
+  }
+}
diff --git a/apps/relayer/ts/message/types.ts b/apps/relayer/ts/message/types.ts
new file mode 100644
index 000000000..cd15824c2
--- /dev/null
+++ b/apps/relayer/ts/message/types.ts
@@ -0,0 +1,13 @@
+/**
+ * Publish messages return type
+ */
+export interface IPublishMessagesReturn {
+  /**
+   * Transaction hash
+   */
+  hash: string;
+  /**
+   * IPFS hash for messages batch
+   */
+  ipfsHash: string;
+}
diff --git a/apps/relayer/ts/message/validation.ts b/apps/relayer/ts/message/validation.ts
new file mode 100644
index 000000000..598910ddf
--- /dev/null
+++ b/apps/relayer/ts/message/validation.ts
@@ -0,0 +1,32 @@
+import { ValidatorConstraint, ValidatorConstraintInterface } from "class-validator";
+import { PubKey } from "maci-domainobjs";
+
+/**
+ * Validate public key
+ */
+@ValidatorConstraint({ name: "publicKey", async: false })
+export class PublicKeyValidator implements ValidatorConstraintInterface {
+  /**
+   * Try to deserialize public key from text and return status of validation
+   *
+   * @param text - text to validate
+   * @returns status of validation
+   */
+  validate(text: string): boolean {
+    try {
+      const [x, y] = PubKey.deserialize(text).asArray();
+      return Boolean(new PubKey([x, y]));
+    } catch (error) {
+      return false;
+    }
+  }
+
+  /**
+   * Return default validation message
+   *
+   * @returns default validation message
+   */
+  defaultMessage(): string {
+    return "Public key ($value) is invalid";
+  }
+}
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index ca2d6a5b6..fe81febef 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -149,6 +149,9 @@ importers:
       maci-contracts:
         specifier: workspace:^2.5.0
         version: link:../../packages/contracts
+      maci-domainobjs:
+        specifier: workspace:^2.5.0
+        version: link:../../packages/domainobjs
       mustache:
         specifier: ^4.2.0
         version: 4.2.0