EBank Microservices

Spring Cloud banking platform: customers, accounts, service discovery, an API gateway, a Spring AI chatbot (REST, Discord, Telegram), MCP tools, and an Angular operations console.

The Angular app talks only to the Gateway. Discord and Telegram talk to EBank Bot directly.

Contents

• Architecture
• Services
• Prerequisites
• Run the platform
• Angular frontend
• Service APIs
• EBank Bot
• Project structure
• Tech stack
• How to verify

Architecture

[ Angular / Telegram / Discord ]
          |
          v
   gateway-service          (Angular only; Discord/Telegram skip Gateway)
          |
          v
  discovery-service (Eureka)
          |
   +------+------+
   |             |
   v             v
customer-service  ebank-service
   |             |
   +------+------+
          |
     OpenFeign + Circuit Breaker (EBank → Customer)
          ^
          |
      ebank-bot  (ChatClient + MCP clients → both services)

• Gateway (9999) routes by Eureka service id: /CUSTOMER-SERVICE/**, /EBANK-SERVICE/**, /EBANK-BOT/**.
• EBank Service loads customers with OpenFeign (CUSTOMER-SERVICE) and a Resilience4j Circuit Breaker (customerService) on account list and by-id lookup. Fallback customer: name Not Available, email not available.
• Customer Service and EBank Service expose MCP Streamable HTTP at /mcp. EBank Bot uses those tools through Spring AI ChatClient.
• OpenFeign and Circuit Breaker are implemented. Retry, RateLimiter, Bulkhead, and TimeLimiter are not used.
• Later stages: Config Server, Keycloak, Docker.

Services

Service	Port	Role
discovery-service	8761	Eureka registry
customer-service	8056	Customer REST + MCP (/mcp)
ebank-service	8057	Account REST + MCP (/mcp) + Feign to customers
ebank-bot	8058	Chat REST, Discord, Telegram → EBankAgent
gateway-service	9999	Single HTTP entry; Eureka Discovery Locator
angular-front	4200	Accounts, Customers, Bot UI via Gateway

Prerequisites

• JDK 21 (JAVA_HOME must point to JDK 21)
• Apache Maven 3.9+
• Node.js 24+ and npm (for angular-front)
• OPENAI_API_KEY for live chatbot answers (not stored in the repository)

Run the platform

Start order: Discovery → Customer → EBank → EBank Bot → Gateway → Angular.

From the repository root:

mvn -pl discovery-service spring-boot:run
mvn -pl customer-service spring-boot:run
mvn -pl ebank-service spring-boot:run
mvn -pl ebank-bot spring-boot:run
mvn -pl gateway-service spring-boot:run

cd angular-front
npm start

Open http://localhost:4200 (redirects to /accounts).

Angular frontend

CSS, no SSR. HttpClient uses http://localhost:9999 only. Gateway CORS allows Origin http://localhost:4200.

Page	URL	Backend
Accounts	http://localhost:4200/accounts	GET /EBANK-SERVICE/accounts (includes customer name/email)
Customers	http://localhost:4200/customers	GET /CUSTOMER-SERVICE/customers
Bot	http://localhost:4200/bot	GET /EBANK-BOT/chat/stream (Ask). GET /EBANK-BOT/chat remains in code

Use Refresh on Accounts and Customers after the bot creates data. Click an account ID to copy it for bot questions.

Service APIs

Customer Service

mvn -pl customer-service spring-boot:run

Resource	URL
List customers	GET http://localhost:8056/customers
Get customer by ID	GET http://localhost:8056/customers/{id}
Create customer	POST http://localhost:8056/customers
MCP Streamable HTTP	http://localhost:8056/mcp
Health	GET http://localhost:8056/actuator/health
Swagger UI	http://localhost:8056/swagger-ui.html
H2 console	http://localhost:8056/h2-console (JDBC URL jdbc:h2:mem:customerdb)

MCP tools wrap the existing service methods: getAllCustomers, getCustomerById, saveCustomer. REST is unchanged.

EBank Service

mvn -pl ebank-service spring-boot:run

Resource	URL
List accounts	GET http://localhost:8057/accounts
Get account by ID	GET http://localhost:8057/accounts/{id}
Create account	POST http://localhost:8057/accounts
MCP Streamable HTTP	http://localhost:8057/mcp
Health	GET http://localhost:8057/actuator/health
Swagger UI	http://localhost:8057/swagger-ui.html
H2 console	http://localhost:8057/h2-console (JDBC URL jdbc:h2:mem:ebankdb)

BankAccount.customerId is a Long. Nested customer is @Transient (not stored in H2). List and by-id load the customer through CustomerLookupService → Feign CUSTOMER-SERVICE behind the customerService circuit breaker. POST /accounts still validates the customer through Feign with no fallback.

MCP tools: getAllBankAccounts, getBankAccountById, saveBankAccount. Account type is CURRENT or SAVING. There is no by-customer query API; list and filter by customerId.

Discovery Service

mvn -pl discovery-service spring-boot:run

Resource	URL
Eureka dashboard	http://localhost:8761
Health	GET http://localhost:8761/actuator/health

Standalone Eureka Server (register-with-eureka=false, fetch-registry=false). Customer, EBank, Gateway, and EBank Bot register as clients.

Gateway Service

Run after Discovery (8761) is up:

mvn -pl gateway-service spring-boot:run

Resource	URL
Customers via Gateway	GET http://localhost:9999/CUSTOMER-SERVICE/customers
Accounts via Gateway	GET http://localhost:9999/EBANK-SERVICE/accounts
Chat via Gateway	GET http://localhost:9999/EBANK-BOT/chat?query=bonjour
Streamed chat via Gateway	GET http://localhost:9999/EBANK-BOT/chat/stream?query=bonjour
Health	GET http://localhost:9999/actuator/health

Routes come from Eureka Discovery Locator. Static localhost:8056 / 8057 / 8058 routes are not used. The Gateway does not call OpenAI or MCP; it only forwards HTTP.

EBank Bot

Requires OPENAI_API_KEY. Discord and Telegram reuse that key through EBankAgent. Run after Discovery is up:

mvn -pl ebank-bot spring-boot:run

Resource	URL
Chat	GET http://localhost:8058/chat?query=bonjour
Chat (default query bonjour)	GET http://localhost:8058/chat
Chat with conversation	GET http://localhost:8058/chat?query=My%20name%20is%20Mohammed&conversationId=1
Chat via Gateway	GET http://localhost:9999/EBANK-BOT/chat?query=bonjour
Health	GET http://localhost:8058/actuator/health
Swagger UI	http://localhost:8058/swagger-ui.html

GET /chat returns text/plain. EBankAgent uses ChatClient with MessageChatMemoryAdvisor, in-memory ChatMemory, and MCP tools for both backend services. The same conversationId keeps prior messages; omit it to use default. Discord uses discord-{channelId} and Telegram uses telegram-{chatId}. Direct :8058/chat and Gateway /EBANK-BOT/chat both work.

telegrambots 6.9.7.1 brings Jersey onto the classpath. Eureka would otherwise pick an incomplete Jersey transport, so EBank Bot sets eureka.client.jersey.enabled=false and still registers as EBANK-BOT.

Tokens

Do not commit tokens. Supply them as environment variables or local overrides:

Variable / property	Purpose
OPENAI_API_KEY / spring.ai.openai.api-key	Required for live chatbot answers
DISCORD_TOKEN / discord.token	Optional; REST /chat starts without it
TELEGRAM_BOT_TOKEN / telegram.bot.token	Optional; omitted means Telegram is not started
TELEGRAM_BOT_USERNAME / telegram.bot.username	Defaults to EBANK-BOT if omitted

Manual Discord test

1. Create an application and bot in the Discord Developer Portal.
2. Enable the Message Content Intent on the bot.
3. Copy the bot token and set DISCORD_TOKEN (never commit it).
4. Invite the bot to a server with permission to read and send messages.
5. Start Discovery → Customer Service → EBank Service → EBank Bot. Gateway is not required.
6. Send a message such as List all customers.

Expected path: Discord → EBankAgent → ChatClient → OpenAI → Customer MCP → Customer Service → Discord.

Manual Telegram test

1. Open Telegram and start a chat with BotFather.
2. Send /newbot and choose a unique display name and a username that ends with bot.
3. Copy the token and set TELEGRAM_BOT_TOKEN (and optionally TELEGRAM_BOT_USERNAME). Never commit them.
4. Start Discovery → Customer Service → EBank Service → EBank Bot. Gateway is not required.
5. Send a message such as List all bank accounts.

Expected path: Telegram → EBankAgent → ChatClient → OpenAI → EBank MCP → EBank Service → Telegram.

Gateway examples (Discovery, Customer, EBank, Bot, and Gateway running, plus OPENAI_API_KEY):

GET http://localhost:9999/EBANK-BOT/chat?query=bonjour
GET http://localhost:9999/EBANK-BOT/chat?query=My%20name%20is%20Mohammed&conversationId=gateway-test
GET http://localhost:9999/EBANK-BOT/chat?query=What%20is%20my%20name%3F&conversationId=gateway-test
GET http://localhost:9999/EBANK-BOT/chat?query=List%20all%20customers&conversationId=gateway-test
GET http://localhost:9999/EBANK-BOT/chat?query=List%20all%20bank%20accounts&conversationId=gateway-test

Project structure

ebank-microservices/
├── customer-service/
├── ebank-service/
├── discovery-service/
├── gateway-service/
├── ebank-bot/
├── angular-front/
├── pom.xml
├── README.md
└── .gitignore

Each service is an independent Maven Spring Boot application. The root pom.xml is an aggregator only.

Tech stack

• Java 21
• Spring Boot 3.5.16
• Spring Cloud 2025.0.3
• Spring AI 1.1.5 (ebank-bot ChatClient + MCP client; customer-service and ebank-service MCP servers)
• Discord: com.zgamelogic:spring-boot-starter-discord 5.0.4
• Telegram: org.telegram:telegrambots 6.9.7.1
• Angular 21 (angular-front)
• Maven

How to verify

From the repository root:

mvn -q test

Or one service:

mvn -q -pl customer-service test

Angular:

cd angular-front
npx ng test