Booking NL

Backend Software Engineer (For independent contractors)

Posted Feb 6, 2026
Project ID: 11116-1
Location
Amsterdam, NH
Hours/week
40 hrs/week
Timeline
11 months
Starts: Feb 6, 2026
Ends: Jan 8, 2027
Payrate range
50 - 100 €/hr

A Software Engineer II is responsible for designing, testing, and maintaining Java-based applications, primarily focusing on backend services, web, and mobile solutions. They translate user requirements into efficient, scalable code using Java frameworks like Spring and Hibernate, while conducting debugging, unit testing, and collaborating with cross-functional teams in agile environments. They will be required to develop and maintain backend services, RESTful APIs, and integrate with relational (MySQL) or NoSQL (Cassandra) databases.

Key Responsibilities


Building software applications

  • Is responsible to build software applications by using relevant development languages and applying knowledge of systems, services and tools appropriate for the business area

  • Is responsible to write readable and reusable code by applying standard patterns and using standard libraries

  • Is responsible to refactor and simplify code by introducing design patterns when necessary

  • Is responsible to ensure the quality of the application by following standard testing techniques and methods that adhere to the test strategy

  • Is responsible to maintain data security, integrity and quality by effectively following company standards and best practices

End to End System Ownership

  • Has sufficient knowledge to own a service end to end by actively monitoring application health and performance, setting and monitoring relevant metrics and act accordingly when violated

  • Has sufficient knowledge to reduce business continuity risks and bus factor by applying state-of-the-art practices and tools, and writing the appropriate documentation such as runbooks and OpDocs

  • Has sufficient knowledge to reduce risk and obtain customer feedback by using continuous delivery and experimentation frameworks

  • Has sufficient knowledge to independently manage an application or service by working through deployment and operations in production

Technical Incident Management

  • Is responsible to address and resolve live production issues by mitigating the customer impact within SLA

  • Is responsible to improve the overall reliability of systems by producing long term solutions through root cause analysis

  • Is responsible to keep track of incidents by contributing to postmortem processes and logging live issues

Architectural Guidance

  • Has basic knowledge to advise product teams towards a technical solution that meets the functional, nonfunctional & architectural requirements by challenging the rationale for an application design and providing context in the wider architectural landscape

  • Has basic knowledge to set a clear direction for a technical capability by evaluating and aligning the target architecture improvements, reframing architectural designs and decisions for varied stakeholder

Software Systems Design

  • Has sufficient knowledge to evaluate possible architecture solutions by taking into account cost, business requirements, technology requirements and emerging technologies

  • Has sufficient knowledge to describe the implications of changing an existing system or adding a new system to a specific area, by having a broad, high-level understanding of the infrastructure and architecture of our systems

  • Has sufficient knowledge to help grow the business and/or accelerate software development by applying engineering techniques (e.g. prototyping, spiking and vendor evaluation) and standards

  • Has sufficient knowledge to meet business needs by designing solutions that meet current requirements and are adaptable for future enhancements


Critical Thinking

  • Is responsible to systematically identify patterns and underlying issues in complex situations, and to find solutions by applying logical and analytical thinking.

  • Is responsible to constructively evaluate and develop ideas, plans and solutions by reviewing them, objectively taking into account external knowledge, initiating 'SMART' improvements and articulating their rationale.

Continuous Quality and Process Improvement

  • Has sufficient knowledge to identify opportunities for process, system and structural improvements (i.e performance gains) by examining and evaluating current process flows, methods and standards.

  • Has sufficient knowledge to design and implement relevant improvements by defining adapted/new process flows, standards, and practices that enable business performance.

  • Is responsible to maintain data security, integrity and quality by effectively following company standards and best practices, guiding more junior members of the team in this topic


Effective Communication

  • Is responsible to deliver clear, well-structured, and meaningful information to a target audience by using suitable communication mediums and language tailored to the audience

  • Is responsible to achieve mutually agreeable solutions by staying adaptable, communicating ideas in clear coherent language and practising active listening

  • Is responsible to ask relevant (follow-up) questions to properly engage with the speaker and really understand what they are saying, by applying listening and reflection techniques

Special knowledge/skills

  • Proficient at building software applications

  • Experience in End to End System Ownership

  • Experience in Software Systems Design

  • Familiar with Architectural Guidance

  • Experience in Technical Incident Management

  • Experience in Technical Leadership

  • Experience in effective Communication

  • Experience in continuous quality improvement

  • Proficient in critical thinking

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