Senior Frontend Performance Engineer – TypeScript / JavaScript / C++ / Java / C#
On site
London, United Kingdom
£ 200,000 / year
Freelance
17-03-2025
Job Specifications
Senior Frontend Performance Engineer – TypeScript / JavaScript / C++ / Java / C#
Location: London (Hybrid – 2 days WFH)
Salary: £150,000 - £200,000 (Permanent)pension, private healthcare, gym membership, 25 days + 8 BH holiday allowance, tech/hardware budget.
Join a fast-growing tech company developing cutting-edge UI solutions used at scale by some of the world's largest enterprises, financial institutions, and tech businesses. With over a million weekly downloads, this product powers real-time, high-performance applications relied upon by 90% of the Fortune 500.
They seek senior engineers who thrive on solving complex technical challenges, optimising performance, and working on large-scale data visualisation and UI frameworks.
What you'll be doing
Optimising front-end performance for real-time, data-intensive applications.
Developing and enhancing a highly optimised, scalable UI framework used by thousands of global enterprises.
Deep diving into JavaScript, TypeScript, and rendering performance to push browser limits.
Solving algorithmic and architectural challenges, ensuring the UI handles millions of data points seamlessly.
Taking complete ownership of features, from ideation to implementation, shaping a product used by millions worldwide.
What you'll bring
Deep Expertise in vanilla / pure JavaScript and TypeScript, with additional experience in C++, Java, C#, or Python.
A strong grasp of data structures, algorithms, and front-end performance optimisation.
Hands-on experience with React, Angular, or Vue, including a deep understanding of DOM rendering.
A problem-solving mindset with the ability to diagnose and fix performance bottlenecks, memory leaks, and rendering inefficiencies.
A passion for building scalable, high-performance UI components.
Why join?
Make an impact by working on a globally used product that powers some of the most demanding applications.
Tackle deep technical challenges at the intersection of front-end performance, data visualisation, and scalability.
Competitive salary of £150,000 - £200,000 plus benefits.
Engineering-first culture where your contributions truly matter.
Hybrid working with two days per week from home.
This is an opportunity to shape the future of high-performance UI. If you're ready to work on cutting-edge technology at massive scale, I'd love to hear from you.
Apply now!
About the Company
Welcome to techstack Recruitment: a digital technology recruitment business for high-growth disruptors and innovators. Our bespoke, high-end recruitment solutions empower our clients to excel in the talent acquisition battle. With our agile, consultative, white-glove approach, we set a new standard in executive search and technical talent acquisition. Through our smart, ethical, and relentless approach to finding talent, we've solved the unique hiring challenges of countless early and growth-stage companies. We are known t... Know more
Related Jobs
- Company Name
- Square One Resources
- Job Title
- Treasury Systems Application Support Engineer
- Job Description
- Job Title: Treasury Systems Application Support Engineer Location: Manchester Salary/Rate: Up to £414 per day INSIDE IR35 Start Date: 31/03/2025 Job Type: Contract Company Introduction We have an exciting opportunity now available with one of our sector-leading financial services clients! They are currently looking for a skilled Treasury Systems Application Support Engineer to join their team for a contract until September Job Responsibilities/Objectives Provide IT application support for Treasury Systems to meet business operational requirements and deliver project and build activity. Provide IT support for all Treasury applications to ensure maximum service availability. Occasional out of hours support to ensure business critical and regulatory tasks are completed. Working as part of a team or on an individual basis, assist with the delivery of strategic projects. Help to deliver BAU small changes and service improvements highlighting associated benefits and key risks as appropriate. Liaise with suppliers and business partners to ensure effective and rapid resolution of technical issues and to deliver all agreed commitments. Engage with Major Incident Managers and Problem Managers in the event of high severity failures and for root cause analysis when requested. Required Skills/Experience The ideal candidate will have the following: Technical and/or functional knowledge of some (not necessarily all) of the following Treasury IT systems. Most valuable would be Swift and/or Kondor+ or an equivalent Treasury Management System. SWIFT and Swift Webaccess services eg. RTGS/Enquiry Link, Bottomline GTX, Bottomline MMCF, Easyway, Crest, Kondor+, Refinitiv real time feed, Bloomberg Unix knowledge Database development skills, particularly SQL or Sybase Other skills: Incident management experience, IT troubleshooting skills Familiarity with call logging systems eg. SMAX Experience of dealing with business customers in an IT service delivery environment If you are interested in this opportunity, please apply now with your updated CV in Microsoft Word/PDF format. Disclaimer Notwithstanding any guidelines given to level of experience sought, we will consider candidates from outside this range if they can demonstrate the necessary competencies. Square One is acting as both an employment agency and an employment business, and is an equal opportunities recruitment business. Square One embraces diversity and will treat everyone equally. Please see our website for our full diversity statement.
- Company Name
- STATION F
- Job Title
- SALES DEVELOPMENT REPRESENTATIVE, UK MARKET
- Job Description
- About Greenly est une entreprise Tech certifiée B-corp fondée en 2019 par Alexis, Matthieu et Arnaud. Elle permet à chaque entreprise de suivre facilement son empreinte carbone, pour participer à la lutte contre le changement climatique. Plus de 2000 entreprises ont déjà fait confiance à Greenly pour réduire efficacement leurs émissions de gaz à effet de serre. Car avec Greenly, les entreprises mesurent précisément, réduisent durablement, contribuent intelligemment et rendent compte de leurs progrès. La plateforme de Greenly associe une collecte intelligente des données à des fonctionnalités avancées pour créer la solution de comptabilité carbone la plus intuitive au monde. Greenly offre également le soutien d'un expert climat tout au long du parcours du client. Job Description Greenly is a B corp certified SaaS company founded in 2019 by Alexis, Matthieu and Arnaud. Greenly is a climate suite that streamlines data collection and analysis through integrations, making the calculation of carbon emissions accurate, intuitive, and affordable. Every day, we work with the goal of enabling our clients to commit to an efficient carbon reduction trajectory and to engage their entire ecosystem (employees, clients, suppliers) around their climate strategy. Greenly supports clients within all industries. Currently working with over 2,500 clients, our assistance goes beyond basic carbon assessments by also including services such as Green IT, lifecycle analysis (LCA), and compliance with SBTi and CSRD initiatives. Our Values Ambition for climate : Minimize GHG emissions, maximize climate impact Agility : Work in small increments: fail fast, learn fast, win fast Ownership : Achieve outstanding results by showing initiative and accountability Feedback paves the way : Succeed as a team by helping others progress Curious to know more ? Take a look at our blog! The Team As part of the Sales Team, you will work alongside +35 talented & ambitious people with one goal in mind : converting as many prospects into customers taking part in our mission of reducing global emissions. Our team is divided by regions : France, UK, US and a Europe team that helps us cover other markets. We work closely with Account Executives but also Partnerships, Sales Operations, Sales Engineering and Marketing. The Role As SDRs, our role is to look for new prospects, reach out to them, and talk to them to understand their needs and know exactly how we can help. You will work hand-in-hand with our Account Executives, generating qualified leads for them, as well as your Team Leader & the rest of the SDR team who will be there to guide you and share best practices with you. Because this role requires feedback to be constant, the possibility to learn fast and grow fast is always present. Becoming an AE after 1,5/2 years is completely feasible, and mobility into other internal teams is too. The Goals Identify companies and people to target on the UK/Irish market. Use cold calling, e-mailing and other channels to reach out to your leads. Qualify these leads & pitch Greenly's value proposition. Follow up with your KPIs & leads. Take part in or lead internal projects in order to continuously improve our processes & ensure continuous growth. The required experience and skills to succeed in this role : A hunter's mindset - you are not afraid to pick up the phone You are autonomous, proactive & a great team player. You are passionate about continuous learning and a true believer in the power of constructive feedback. Are ambitious and you feel most excited when in dynamic and fast-paced environments. Extra Points Go For Candidates Who... Are familiar with lead qualification frameworks and argument management techniques. Have experience using Hubspot, Sales Navigator, Salesloft and/or Lusha. Have experience in entrepreneurship or the associative field. Please note that this role is based in London. We have a very flexible work from home policy, but candidates who are not based in the region will not be considered. The recruitment process Have an introduction call with Sabina, our Talent Acquisition Manager. Meet your future Team Lead for a technical interview. Meet Tom, our BDR/SDR Global Manager. Additional Information Contract Type: Full-Time Location: London Possible partial remote Salary: between 35000 and 45000 / year
- Company Name
- Zest
- Job Title
- Cloud Engineer
- Job Description
- Purpose of job: Our aim is to become a market leader in the provision of Electric Vehicle charging solutions to Local Authorities and Businesses as part of our strategy to lead the transition to zero carbon. The goal is to undertake an ambitious electric vehicle charging installation program, deploying high volume and quality EV installations across the nation. The target areas will be public destination charging locations, primarily deploying fast-charging solution 7.4kW to 22kW with potential 50kW to 200kW rapid solution as and when required. Our aim is to make the world a better place, one charge point at a time. The Zest Platform team are highly skilled technical team providing secure and safe environments for our developers to work in. Our aim is to do everything we can to allow our Software Engineers to focus on delivering quality results cost effectively and following best practices. We work closely with the Software Engineers providing support on technical challenges and guidance to ensure optimised and well architected solutions. We are accountable for the infrastructure delivery across multiple projects providing standardised, centralised where appropriate and consistent results. We also provide a level of support for our production applications as well as administration of our tooling solutions. The Cloud Engineer needs to be self-motivated with strong resiliency and resourcefulness under pressure. They will be required to work closely with and support the Platform team to deliver solutions that make a difference to our IT objectives. They need a strong grounding in DevOps, SecOps and FinOps practices as well as technical skills in public cloud platforms including AWS, strong experience with IaC languages (e.g. Terraform, CDK, CloudFormation) and complex application support. They also need strong experience in observability tooling and configuration. Key Accountabilities: The role is responsible for the following: Design, build and documentation of platform configuration for automation and shared tooling. Monitoring platform security, stability, scalability, connectivity, cost and performance and acting on any findings. Develop and document improvements in platform tools, following the agile development processes through test and into live. Ensure that security standards and AWS architectural recommendations are considered as part of each deployment and built into the development solutions. Investigate and manage administration of new tools and processes for platform, and the IT development team to support improved and more efficient work e.g., backup, change, access requests etc. Understand projects across multiple teams to provide platform support on technical challenges, documenting detailed designs and technical breakdowns of solutions or processes. Any other duties required. Outcome, Results and Key performance indicators: Provision of secure working cloud environments Creation and documentation of reusable automation to support continuous delivery and integration Delivery of secure and cost performant solutions Delivery of high-quality project, solution and tooling documentation Development and delivery of infrastructure for projects as required Successfully meeting the goals of the IT team Key Relationships: Internal – Development Team, QA Team, Solution Architect, CTO, IT Service Team, Finance team, Data Analytics Team External – AWS Support, others as required Knowledge and Skills: At least 10 years public cloud experience Technical support background Experience of DevOps, FinOps and SecOps in Cloud environments Experience of Observability tools such as Promethius and New Relic Experience in alert writing and monitoring Experience of key AWS services such as Security Hub, Trusted Advisor, Cost Explorer, VPC, CloudWatch, EventBridge, Cloud Trail, Control Tower and Organisations Experience of systems administration across a multi-service environment including databases Understanding of AWS Best Practices and Well-Architected Framework Understanding of AWS pricing models Experience of Network design principles and implementation in AWS Experience in a range of programming languages to include: Python, CloudFormation, Terraform, Typescript, CDK and bash script Excellent skills in debugging and trouble shooting Excellent skills in technical writing Behaviours: Self-motivated professional Enthusiastic learner Excellent communication skills at all levels Negotiation and stake holder management skills Patient and adaptable to high pressure situations Approachable and supportive team player and mentor Analytical problem solving Good attention to detail Qualifications: AWS certification, desirable Contract: 6 Month initial contract Salary – up to £500 per day Zest is an equal opportunity employer, committed to the values and ultimately societal benefits of diversity, equity, and inclusion. Please note we will not be working with external agencies in recruitment for this role.
- Company Name
- Vallum Associates
- Job Title
- Program Director - Investment Bank
- Job Description
- We are looking for a Program Director for Investment Bank. Someone who has managed data and cyber security programs with Investment Banks. Required Skills & Experience: Proven experience managing high-value (£15M+) technology programs in global banking. Strong background in program governance, risk management, and agile methodologies. Expertise in handling complex technology transformations, including cloud, AI, data, or enterprise platforms. Exceptional leadership and stakeholder management skills, with experience working at C-suite and executive levels. Strong financial and budget management expertise, ensuring cost optimization and ROI-driven execution. Ability to navigate regulatory and compliance requirements in financial or enterprise environments.