Backend Engineer

Calyptus
Madrid, Spain
24 days ago
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Role details

Contract type
Permanent contract
Employment type
Full-time (> 32 hours)
Experience required
2 years minimum
Working hours
Regular working hours

Tech stack

Java (Programming Language) Application Programming Interfaces (APIs) Artificial Intelligence Amazon Web Services Amazon Elastic Compute Cloud Amazon S3 Cloud Engineering Code Review Databases Database Schema Software Debugging Linux
+19 more
Elasticsearch Fault Tolerance MongoDB MySQL NoSQL Query Optimization Software Engineering SQL Stored Procedures Spring-boot Caching Backend Amazon Relational Database Service Information Technology Low Latency Functional Programming Api Design Api Gateway Data Pipelines Microservices

Job description

Want to put your job search on autopilot?Join our platform, complete a 6-minute AI screening interview, and get auto-applied to 100s of high-paying roles.Sign up now at and let the opportunities come to you.The RoleWe are seeking an experienced Backend Engineer who is excited to build the technical backbone of a new generation travel platform.You’ll work with Java and Spring Boot to design and implement scalable, resilient backend services, and use databases like MySQL, MongoDB, and ElasticSearch to power search, personalization, and booking flows.Familiarity with Linux systems, AWS, and microservices architecture will help you ship reliable systems at scale.Core ResponsibilitiesDesign, develop, and scale backend systems using Java and Spring Boot.Create low-latency search infrastructure (ElasticSearch, caching, query optimization).Build and maintain supplier integrations across hotels, chains, and experiences, ensuring stability and fault tolerance.Implement real-time personalization and ranking logic to improve customer discovery and booking conversion.Enable AI-powered experiences by building APIs, data pipelines, and scalable systems that support recommendations, personalization, and conversational interfaces.Develop and maintain database schemas, queries, and stored procedures (MySQL, MongoDB, ElasticSearch).Deploy and optimize services on Linux and AWS environments (EC2, S3, RDS, Lambda, API Gateway).Implement and evolve microservices architecture; design APIs for communication between services.Monitor backend systems in production, troubleshoot issues, and deliver timely fixes.Collaborate with product, growth, and engineering peers to translate customer needs into backend solutions.Participate in code reviews, debugging, and documentation to ensure quality and maintainability.Stay current with new backend and AI technologies, bringing forward ideas for innovation and scale.Candidate RequirementsBachelor’s or Master’s degree in Computer Science, Software Engineering, or a related field.2-5 years of backend development experience with Java and Spring Boot.Strong knowledge of relational and NoSQL databases (MySQL, MongoDB) and ability to design efficient schemas, queries, and stored procedures.Familiarity with ElasticSearch and interest in building low-latency search systems.Hands-on experience with Linux systems and deploying/maintaining backend services in production.Experience with AWS services (EC2, S3, RDS, Lambda, API Gateway) and cloud-native deployments.Understanding of microservices architecture and proven experience designing and implementing APIs for service communication.Strong problem-solving and analytical skills with a focus on scalability, reliability, and performance.Excitement to work in an AI-first company, building systems that power personalization, recommendations, and AI-driven experiences at scale.Excellent communication skills and the ability to collaborate effectively across product, growth, and engineering teams.Disclaimer: Calyptus uses an automated assessment tool that scores applicants.#J-*****-Ljbffr

Requirements

Bachelor’s or Master’s degree in Computer Science, Software Engineering, or a related field. 2-5 years of backend development experience with Java and Spring Boot. Strong knowledge of relational and NoSQL databases (MySQL, MongoDB) and ability to design efficient schemas, queries, and stored procedures. Familiarity with ElasticSearch and interest in building low-latency search systems. Hands-on experience with Linux systems and deploying/maintaining backend services in production. Experience with AWS services (EC2, S3, RDS, Lambda, API Gateway) and cloud-native deployments. Understanding of microservices architecture and proven experience designing and implementing APIs for service communication. Strong problem-solving and analytical skills with a focus on scalability, reliability, and performance. Excitement to work in an AI-first company, building systems that power personalization, recommendations, and AI-driven experiences at scale. Excellent communication skills and the ability to collaborate effectively across product, growth, and engineering teams. Disclaimer: Calyptus uses an automated assessment tool that scores applicants. #J-*****-Ljbffr

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Good distractions

Talks and stories from around this role — technically off-topic, practically not.

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Comparing traditional SQL tables versus NoSQL non-tabular databases

Stanimira Vlaeva · JS Congress

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Simulating a Linux terminal and running Spring Boot

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Terminology differences between relational and NoSQL databases

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