Contract Role: Senior Ember.js Engineer Outside IR35 Fully Remote

ZipRecruiter; London; Remote; GBP 125,000 - 150,000; Full time

Job summary

A well-established financial services firm is seeking a Senior Ember.js Engineer to upgrade legacy applications to Ember 6.x and Node.js v20+. You’ll work on modernizing the codebase within a monorepo, ensuring a smooth upgrade process, and maintaining test coverage. This remote role requires at least 5 years of experience in Ember.js and solid knowledge of Node.js.

Qualifications

• 5+ years of experience upgrading and maintaining Ember.js applications.
• Solid grasp of Node.js version migrations, especially v20+.
• Familiarity with monorepo structures.

Responsibilities

• Upgrade Ember.js from ~v3.20.5 to Ember 6.x.
• Maintain comprehensive test coverage.
• Identify and deprecate outdated libraries.

Skills

Upgrading Ember.js applications

Node.js environments

Monorepo structures

Ember Engines

Testing mindset

Good communication

Tools

Ember.js

Node.js

Lerna

Yarn Workspaces

AWS Amplify

QUnit

Job description

Job Description

• Location: Remote (UK)
• Duration: 2-3 months
• Start: 21st July 2025
• Engagement: Outside IR35
• 5 Years ember experience required (Minimum requirement)

The Opportunity

A well-established financial services product business is looking for a Senior Ember.js Engineer to lead a critical upgrade project across its legacy Ember applications. These applications are part of a wider FX payments back-office platform, with components that have not been updated in several versions and are now reliant on unsupported versions of Ember.js and Node.js.

This is a focused engineering engagement. You’ll work within a mono-repo ecosystem, modernising the codebase, resolving dependencies, and ensuring successful delivery of a clean, stable, and production-ready upgrade.

What is Required.

• Working closely with internal engineering leadership and DevOps support, you will:
• Upgrade Ember.js from ~v3.20.5 to Ember 6.x (Octane).
• Upgrade Node.js to v20+ across all associated packages.
• Migrate and validate shared packages within a monorepo (Lerna/Yarn Workspaces).
• Run and maintain comprehensive test coverage (unit, integration, and UAT).
• Identify and deprecate outdated libraries and plugins.
• Optionally consolidate “common” and “domain-common” packages into a single repo (without impacting delivery timelines)

Tech Stack:

• Frontend: Ember.js (Octane), Glimmer, Handlebars
• Tooling: Lerna, Yarn Workspaces, ESLint, Prettier
• Testing: QUnit, qunit-dom, ember-qunit
• CI/CD: AWS Amplify
• Auth: Keycloak (OAuth2 integration)
• : TypeScript, JavaScript
• Misc: Ember Engines, Babel, Sass, ember-auto-import, ember-fetc

Skill-Set

• Deep experience upgrading and maintaining Ember.js applications (ideally 3.x → 5.x/6.x).
• Solid grasp of Node.js environments and version migrations (especially v20+).
• Familiarity with monorepo structures, including Lerna and Yarn Workspaces.
• Experience working with Ember Engines and component libraries.
• Strong testing mindset – you’ve worked with QUnit or equivalent test runners in Ember.
• Good communicator – able to work autonomously and update stakeholders clearly.

Deliverables

• Technical Upgrade Plan
• Comprehensive Test Plan and Cases
• Clean builds and validated UAT release
• Post-upgrade performance and stability report