A Spring Boot service that converts an amount from one cryptocurrency to another using CoinMarketCap (CMC), persists each conversion as a history record, and exposes pageable search & discovery endpoints. All responses are wrapped in CustomResponse<T>; paged payloads use CustomPagingResponse<T>.

• Client sends POST /api/convert with ConvertRequest: { from, to, amount } (e.g., BTC → ARB, amount=100).
• Service fetches the conversion rate from CMC, computes convertedAmount, and persists a record:
  • transactionId (UUID)
  • createdAt (ISO-8601)
  • from, to, amount, convertedAmount
• Returns 201 Created with CustomResponse<CryptoConvert> containing the saved record.

POST /api/convert/history accepts FilterServicePagingRequest and returns CustomPagingResponse<CryptoConvertResponse>. Filtering supports:

• from, to (symbols)
• amount range: minAmount .. maxAmount
• convertedAmount range: minConvertedAmount .. maxConvertedAmount
• createdAt range: createdAtFrom .. createdAtTo
• transactionIdContains (substring)

Pagination & sorting are provided in the request (e.g., pageNumber, pageSize, sortBy, sortDirection).

• GET /api/convert/map returns a paged list of cryptocurrencies (name & symbol) via CMC /v1/cryptocurrency/map.
• Query params:
  • page (1-based, default 1, min 1)
  • size (default 20, range 1..5000)
• Response: CustomPagingResponse<CryptoNameSymbolResponse> with standard paging metadata.

• 201 Created — Successful conversion persisted (/api/convert)
• 200 OK — Successful paged responses (/history, /map)
• 400 Bad Request — Validation errors (invalid symbols, amounts, or paging inputs)
• 502 Bad Gateway — Upstream CMC call failed or unavailable (convert/map)

CMC results are cached to reduce latency and request volume. Cache eviction runs on a fixed schedule configured via cmc.cache-ttl and a lifecycle hook (@PostConstruct) to ensure fresh state on startup.

The controller is annotated with detailed @Operation and @ApiResponse metadata. Explore at: http://localhost:1927/swagger-ui/index.html (port configurable).

Endpoints Summary

• Java 25
• Spring Boot 3.0
• Restful API
• Open Api (Swagger)
• Maven
• Junit5
• Mockito
• Integration Tests
• Mapstruct
• Resilience4j
• Resilience4j Rate Limiter
• Resilience4j Retry
• Resilience4j Circuit Breaker
• Spring Cache
• Docker
• Docker Compose
• CI/CD (Github Actions)
• Postman
• Prometheus
• Grafana
• Kubernetes
• JaCoCo (Test Report)
• AOP
• Jenkins

Import postman collection under postman_collection folder 

MONGO_DB_HOST=localhost MONGO_DB_PORT=27017 MONGO_DB_NAME=cryptoexchangedatabase COIN_MARKET_CAP_API_KEY={YOUR_COIN_MARKET_CAP_API_KEY} 

http://localhost:1927/swagger-ui/index.html 

After the command named mvn clean install completes, the JaCoCo report will be available at:

target/site/jacoco/index.html 

Navigate to the target/site/jacoco/ directory.

Open the index.html file in your browser to view the detailed coverage report.

To build and run the application with Maven, please follow the directions shown below;

$ git clone https://github.com/Rapter1990/cryptoexchangeapi.git $ cd cryptoexchangeapi $ mvn clean install $ mvn spring-boot:run

The application can be built and run by the Docker engine. The Dockerfile has multistage build, so you do not need to build and run separately.

Please follow directions shown below in order to build and run the application with Docker Compose file;

$ cd cryptoexchangeapi $ docker-compose up -d

If you change anything in the project and run it on Docker, you can also use this command shown below

$ cd cryptoexchangeapi $ docker-compose up --build

To monitor the application, you can use the following tools:

• Prometheus:
  Open in your browser at http://localhost:9090
  Prometheus collects and stores application metrics.

• Grafana:
  Open in your browser at http://localhost:3000
  Grafana provides a dashboard for visualizing the metrics.
  Default credentials:

  • Username: admin
  • Password: admin

Define prometheus data source url, use this link shown below

http://prometheus:9090 

To run the application, please follow the directions shown below;

• Start Minikube

$ minikube start

• Open Minikube Dashboard

$ minikube dashboard

• Revise CMC_API_KEY in cryptoexchangeapi-secrets.yml according to your usage

• To deploy the application on Kubernetes, apply the Kubernetes configuration file underneath k8s folder

$ kubectl apply -f k8s

• To open Prometheus, click tunnel url link provided by the command shown below to reach out Prometheus

minikube service prometheus-service

• To open Grafana, click tunnel url link provided by the command shown below to reach out Prometheus

minikube service grafana-service

• Define prometheus data source url, use this link shown below

http://prometheus-service.default.svc.cluster.local:9090 

https://hub.docker.com/repository/docker/noyandocker/cryptoexchangeapi/general https://hub.docker.com/repository/docker/noyandocker/cryptoexchangeapi-jenkins/general 

• Go to jenkins folder
• Run docker-compose up -d
• Open Jenkins in the browser via localhost:8080
• Define credentials for Github General token used by GIT_REPO_ID and docker-hub-credentials for Docker Username and Password
• Go to pipeline named cryptoexchangeapi
• Run Pipeline
• Show Pipeline Step to verify if it succeeded or failed

Click here to show the screenshots of project

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Figure 14

Figure 15

Figure 16

Figure 17

• Sercan Noyan Germiyanoğlu