Senior Developer

The United Nations Environment Programme (UN Environment) is the leading global environmental authority that sets the world's environmental agenda, promotes the coherent implementation of the environmental dimension of sustainable development within the United Nations system and serves as an authoritative advocate for the environment.

The consultant will:

• Provide senior technical advice and troubleshooting for complex issues affecting the corporate website, Starter Kit and priority web-platform migrations.
• Review architecture, code, configurations and implementation approaches for significant or high-risk changes and advise developers on required corrective action.
• Support technical readiness of major releases and migrations, with particular attention to dependencies, security, performance, integrations and rollback requirements.
• Provide specialist support, where required, on Drupal architecture, reusable components, React/Next.js integrations, APIs, OpenSearch and related platform functionality.
• Advise on technical standards and reusable implementation patterns that support maintainability and consistency across UNEP web platforms
• Support resolution of priority production issues that require senior developer expertise.
• Coach the designated replacement through practical review of the principal systems, repositories, development workflows, deployment processes, architecture and outstanding technical issues.
• Develop a practical Drupal technical training and operations manual for use by UNEP developers and the designated replacement, covering development workflows, administration, deployment, maintenance, upgrades and troubleshooting.
• Develop and maintain comprehensive technical documentation for UNEP’s Drupal environment, including architecture, modules, themes, configurations, reusable components, integrations, APIs, search, deployment processes, dependencies, maintenance and troubleshooting procedures.

Qualifications/special skills

• A master’s degree in computer science, information systems, software engineering or other related field is required.
• A first-level university degree in combination with two additional years of qualifying experience may be accepted in lieu of the master’s degree.
• A minimum of five years of progressively responsible professional experience in web development, including substantial senior-level experience with PHP and Drupal is required.
• Demonstrated experience providing technical leadership for complex websites or multi-site digital platforms is required.
• Strong experience with Drupal architecture, themes, modules, configuration, reusable components, website migrations and modernization of enterprise web platforms is required.
• Experience with JavaScript and modern front-end technologies, preferably React and Next.js. is required.
• Experience designing and integrating APIs and working with enterprise search technologies such as Elasticsearch or OpenSearch is required. Strong knowledge of Git, code review and CI/CD deployment workflows is required.
• Experience applying security, accessibility, performance and maintainability standards to web platforms is required.
• Demonstrated experience reviewing the work of other developers, providing senior technical guidance, producing technical documentation and training materials and transferring technical responsibilities to other technical staff or successor personnel is required.
• Strong communication skills and the ability to work effectively in a multicultural and international environment is desirable.

Deadline : Oct 20, 2026

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