Technical Leadership Jobs in London

1 to 25 of 329 Technical Leadership Jobs in London

Software Engineering Manager (2 vacancies)

London, United Kingdom
Hybrid / WFH Options
Low Carbon Contracts Company
Summary: Responsible for leading LCCC talented engineers in designing, developing, and delivering high-quality software solutions. You will play a pivotal role in fostering an innovative engineering culture, ensuring technical excellence, and aligning development efforts with business goals. Key Responsibilities Lead, mentor, and manage a medium-sized team of 12 software engineers through project lifecycles, from planning to deployment. … Own resource management process providing practical and effective capacity assessments. Own the technical roadmap, architecture decisions, and code quality for your team. Collaborate cross-functionally with product managers, designers, and other stakeholders to define technical requirements and deliver solutions. Drive best practices in software development, including code reviews, CI/CD, testing, and documentation. Monitor performance metrics and … Identify opportunities for continuous improvement in tools, processes, and performance. Skills Knowledge and Expertise Essential: Software Engineering Background: Strong background in software development with hands-on experience delivering complex technical solutions. Technical Leadership: Ability to define and own the engineering roadmap, drive technical strategy, and ensure system performance, scalability, and stability. People Management: Proven experience leading More ❯
Employment Type: Permanent
Salary: GBP Annual
Posted:

Senior Software Engineer

London, United Kingdom
Global Processing Services
process. Optimize applications for maximum speed, scalability, and security. Stay abreast of emerging trends and technologies in cloud computing and issuer processing to drive continuous innovation and improvement. Provide technical leadership and mentorship to junior engineers, promoting best practices in software development. Troubleshoot, debug, and upgrade existing systems, ensuring high performance and responsiveness to requests. Participate in code … reviews, contributing to the maintenance of high coding standards and improving the overall quality of the codebase. Technical Skills and Experience Needed Proven experience with cloud-based technology, and services, preferably within AWS. Expertise in both Frontend and Backend software solution development Experience with Agile development methodologies and SecDevOps practices. Excellent knowledge of secure coding practices inline. Strong knowledge … data structures and algorithms. Excellent problem-solving skills and the ability to work in a fast-paced, evolving environment. Strong communication and collaboration skills, with the ability to articulate technical concepts to non-technical stakeholders. A commitment to continuous learning and improvement, both in personal capacity and within the context of the team. Prior experience with payment systems More ❯
Employment Type: Permanent
Salary: GBP Annual
Posted:

Java Technical Lead

London Area, United Kingdom
Ascendion
About the Role: We are seeking an experienced and visionary Technical Lead with deep expertise in Java Spring Boot, microservices architecture, and solution design to lead the backend engineering efforts of our enterprise platforms. This role requires strong architectural acumen, hands-on coding capability, and a leadership mindset to guide teams across the full software development lifecycle. Exposure … and JWT. • Collaborate with mobile app teams to ensure backend services are optimized for mobile-specific use cases such as performance, caching, and offline access. • Own end-to-end technical delivery, including code quality, performance optimization, security best practices, and CI/CD integration. • Perform code and design reviews, define technical standards, and mentor developers across the team. … Required Qualifications: • Bachelor’s or Master’s degree in computer science, Engineering, or related field. • 10+ years of professional experience in backend development, with at least 3+ years in technical leadership or solution design roles. • Strong expertise in Java, Spring Boot, and the Spring ecosystem (Spring MVC, Data, Security). • Proven experience architecting and deploying microservices-based systems More ❯
Posted:

Java Technical Lead

City of London, London, United Kingdom
Ascendion
About the Role: We are seeking an experienced and visionary Technical Lead with deep expertise in Java Spring Boot, microservices architecture, and solution design to lead the backend engineering efforts of our enterprise platforms. This role requires strong architectural acumen, hands-on coding capability, and a leadership mindset to guide teams across the full software development lifecycle. Exposure … and JWT. • Collaborate with mobile app teams to ensure backend services are optimized for mobile-specific use cases such as performance, caching, and offline access. • Own end-to-end technical delivery, including code quality, performance optimization, security best practices, and CI/CD integration. • Perform code and design reviews, define technical standards, and mentor developers across the team. … Required Qualifications: • Bachelor’s or Master’s degree in computer science, Engineering, or related field. • 10+ years of professional experience in backend development, with at least 3+ years in technical leadership or solution design roles. • Strong expertise in Java, Spring Boot, and the Spring ecosystem (Spring MVC, Data, Security). • Proven experience architecting and deploying microservices-based systems More ❯
Posted:

Engineering Manager (Full Stack) - Ethical Marketplace

London, United Kingdom
Hybrid / WFH Options
Wolf & Badger
across our web platform, with technologies including TypeScript with React on the front end and Python with Django on the back end. You will be responsible for setting the technical direction, overseeing architecture, and driving the implementation of scalable and user-centric features. You'll collaborate closely with product managers, designers, and engineers across the stack to deliver seamless … our beautiful office in Soho, Central London. Candidates must be based within a commutable distance of the office and be happy to commit to this requirement. Accountabilities and Responsibilities: Technical Leadership & Innovation: Lead and support a cross-functional engineering team, with hands-on knowledge of both front-end (TypeScript/React) and back-end (Python/Django) technologies. … engineers, and other cross-functional teams to define and execute on project goals. Ensure seamless communication across teams to ensure the back end vision aligns with product strategy and technical feasibility. Champion accessibility, usability, and performance as core principles in every design and implementation. Project Delivery & Quality Assurance: Manage timelines, set priorities, and allocate resources effectively to ensure timely More ❯
Employment Type: Permanent
Salary: GBP Annual
Posted:

Senior Full Stack Software Engineer

London, United Kingdom
Fasanara
Monitoring, and Treasury. Collaborate cross-functionally with investment, operations, and data teams to translate complex business workflows into efficient, maintainable software solutions. Drive the full software development lifecycle - from technical design and implementation to testing, deployment, and production monitoring. Contribute across the stack, including backend services, frontend interfaces, and data engineering pipelines as needed. Provide technical leadership and mentorship to more junior team members, fostering a culture of learning, accountability, and continuous improvement. A degree in Computer Science, Engineering, or a related technical field, or equivalent hands-on experience in a professional environment. Proven experience designing and developing robust APIs, microservices, and backend systems that power business-critical workflows. Experience with at least one of … cloud infrastructure, particularly AWS. Competency with standard development and collaboration tools (e.g., Git, GitLab, CI/CD workflows). Excellent communication and stakeholder management skills; you're comfortable discussing technical trade-offs with both engineers and non-technical colleagues. Bonus: A portfolio, GitHub profile, or examples of personal projects that showcase your technical abilities and creativity. Competitive More ❯
Employment Type: Permanent
Salary: GBP Annual
Posted:

Senior Site Reliability Engineer

London, United Kingdom
Hybrid / WFH Options
Stratospherec Ltd
Platforms teams with globally-dispersed Site Reliability and Platform Engineers in a "follow the sun" model to operate our products on a multi-region cloud platform. Role Responsibilities: Provide technical leadership and mentoring within the team through knowledge sharing sessions, pair programming, code reviews and solution design Identify and implement technical solutions to improve platform reliability, including More ❯
Employment Type: Permanent
Salary: £85000 - £90000/annum Excellent Benefits package
Posted:

Test Environment Lead Engineer (5+ Years Exp)

London, United Kingdom
Hybrid / WFH Options
Infuse Consulting Ltd
telco providers, retailers, finance houses, leading system integrators and Fintech companies. If you join Infuse, you will work across a variety of projects and domains learning and leveraging innovative technical solutions to help solve our clients' challenges and providing them with high quality software and real business benefits. We will support you every step of the way and have … seeking a highly skilled and experienced Test Environment Lead Engineer with minimum 5 years of experience who will be responsible for designing, establishing, and maintaining robust test environments. Your leadership, technical proficiency, and strategic thinking will be crucial in ensuring the quality and efficiency of our testing workflows. Key Responsibilities Test Environment Strategy and Leadership: Develop and … execute a comprehensive test environment strategy aligned with project objectives and quality standards. Lead a team of engineers, providing mentorship, guidance, and technical leadership in the field of test environment management. Environment Architecture and Setup: Architect complex and versatile testing environments that accurately emulate production configurations and scenarios. Oversee the setup, configuration, and maintenance of diverse environments, ensuring More ❯
Employment Type: Permanent
Salary: GBP Annual
Posted:

Application Architect - Risk Technology, Vice President

London, United Kingdom
Citigroup Inc
focus. Our users rely on the system for an integrated view of trades, collateral, market data, across many dozens of sources. Ideal Background Participates in architecture governance bodies. Provide technical leadership to the team of Software Engineers/Analyst. Ensure application design adheres to the appropriate architectural and design patterns in the systems. Executes creative architecture solutions, design … development, and technical troubleshooting with ability to think beyond routine or conventional approaches to build solutions and break down technical problems. Identifies opportunities to eliminate or automate remediation of recurring issues to improve overall operational stability of software applications and systems. Design & develop scalable micro-services to build a functional component that will support Risk Management functions. Partner … Jenkins, SonarQube, JIRA, Any secure coding toolkits. Education Bachelors or equivalent in the field of engineering Master's degree an advantage Other Competencies • Excellent oral and written English • Strong leadership • Ability to collaborate in a large global team and influence key architectural decisions across groups • Ability to work well under pressure Citi is an equal opportunity and affirmative action More ❯
Employment Type: Permanent
Salary: GBP Annual
Posted:

Senior Full Stack Engineer

London, United Kingdom
Two Circles Ltd
we deliver work for sports and entertainment businesses of all shapes and sizes all over the world JOB DESCRIPTION As part of our ongoing growth, we are expanding our technical team and looking for an experienced Senior Full Stack Engineer to join our London office. The chosen person will play an important role in influencing the rapidly growing Two … Circles technology proposition and will be responsible for technical seniority, supporting technology consulting projects, identifying and advising on appropriate solutions for our clients. You will have a track record of designing and delivering high-quality digital solutions over the last 7+ years and have a keen interest in the application of technology in the sports industry. If this sounds … like you, please get in touch. Key Responsibilities Work closely with Engineering Managers, Engineering Leads and Product Managers to understand problems and define technical scope for global sports properties. Being an advocate for developer experience and a keen interest in continually improving it. Encouraging a blameless culture of continuous improvement and technical excellence. Creation of architectural diagrams and More ❯
Employment Type: Permanent
Salary: GBP Annual
Posted:

Principal Data Engineer

London, United Kingdom
Storio group
accelerates a decentralised-by-design data adoption model within the business. We care about providing trustable, usable data that meets business needs. We want you to own and drive technical excellence within your team to make this organisation-level change happen. You're a software engineering technical leader at heart. You thrive in the data engineering and analytics … engineering domain. You care deeply about customer outcome-focused data engineering excellence. Areas of Expertise Technical Leadership: - Extensive experience in data engineering, including designing, building, and maintaining robust and scalable data platforms that enable key business initiatives. - Proven ability to lead technical design and architecture discussions, influencing technical strategy and decisions across the organization. - Experience mentoring … and coaching junior engineers, fostering a culture of technical excellence within the team. Data Engineering Expertise: - Deep understanding of data engineering principles and best practices, including data modeling, observable ETL/ELT processes, data warehousing, and data governance. - Proficiency in data manipulation languages (e.g., SQL/DBT) and programming languages relevant to data engineering (e.g., Python). - Experience with More ❯
Employment Type: Permanent
Salary: GBP Annual
Posted:

Cross-Asset Markets Cloud KDB Lead

London, United Kingdom
Hybrid / WFH Options
Citigroup Inc
its long-term stability and reliability. As a Team Lead, you will also be responsible for guiding and mentoring team members, fostering a collaborative and high-performing environment. Responsibilities: Technical Leadership: Lead the development of the Kdb+ target state architecture in collaboration with senior developers. Provide technical guidance and mentorship to team members, fostering their growth and More ❯
Employment Type: Permanent
Salary: GBP Annual
Posted:

Reporting Technical Delivery Lead Data / DevOps

London, South East, England, United Kingdom
Pontoon
Reporting Technical Delivery Lead (Data/DevOps) Banking Hybrid in London: 3-4 days per week onsite 6 months+ £800 - £900 per day In short: We're building a new, systematic data platform with repeatable capability using DevOps principles and we need a Technical Lead to deliver this. Having technical experience with data and devops is essential … and so is the ability to deliver, report and manage the team. In full: We are seeking a seasoned and hands-on Reporting Technical Delivery Lead to drive the delivery of our strategic reporting and analytics platforms across our EMEA division. This role is critical in enabling front-office, risk, compliance, and operations teams to make data-driven decisions … initiatives in a highly regulated, fast-paced environment. The ideal candidate should have a strong background in robust enterprise delivery of reporting/data visualisation platforms, project management, and leadership skills to drive the team towards achieving strategic objectives. They should be curious about the technology and design of the reporting platforms as well as how the delivery team More ❯
Employment Type: Contractor
Rate: £800 - £900 per day
Posted:

Full Stack Technical Lead (6 Month Contract) - Immediate Start

London, United Kingdom
Hybrid / WFH Options
The ECA International Group
to experience a rewarding career where your potential is celebrated, and your journey to excellence begins. About the Role We are seeking a highly skilled and experienced Full Stack Technical Lead (6 month contract) to join our Technology & Engineering team at ECA International on a. This is a hands-on leadership role suited to a self-starter with … strong technical expertise and a passion for building robust, scalable solutions using Node.js, JavaScript/TypeScript, and React. The successful candidate will be responsible for guiding technical direction, mentoring developers, fostering a high-performing team culture, and owning end-to-end project delivery. You will lead by example, driving best practices in software development while promoting an AI … approach to improve productivity and innovation across the development lifecycle. This is an exciting opportunity for someone who thrives on building quality software, collaborating across teams, and shaping both technical and team strategy. Key Responsibilities: Team Leadership : Lead and mentor developers, fostering a collaborative, inclusive, and high-performing team environment. Technical Direction : Set the technical vision More ❯
Employment Type: Permanent
Salary: GBP Annual
Posted:

Lead Software Engineer

London, United Kingdom
Endeavour Recruitment Solutions
Engineer will be part of an agile cross-functional team in developing and maintaining our client flagship digital platform. As a Lead Software Engineer , you will be providing expert technical leadership in the design of our client's cloud-based platform. You will help define the engineering standards, implement best practice, and contribute to their technical and … product roadmap. You will act as a coach and mentor, providing technical leadership to the engineering teams. Profile: You will have a passion and solid experience in designing solutions that are to a high-quality coding standard, secure, scalable, and resilient. to solve business needs. You have demonstrable experience in setting the technical direction of the engineering … pillar by having a deep understanding of the needs of the organization around you. You influence this direction through a consensus-based approach using your people leadership skills and technical expertise. You will have technical experience and knowledge of the following: Expert level experience with software development on the Microsoft tech stack using .NET, ReactJS, REST APIs More ❯
Employment Type: Permanent
Salary: GBP Annual
Posted:

Senior Data Engineer

London, United Kingdom
Gunvor Group
and driving innovation in data-driven decision-making across the Natural Gas and Power value chain. This role reports to the Data Engineer Lead. Main Responsibilities Data Architecture & Engineering Leadership Architect and implement robust, scalable, and secure data pipelines and platforms tailored to the needs of Natural Gas and Power trading, including real-time market data ingestion, time-series … datasets from public and proprietary sources to support market intelligence and forecasting. Evaluate and implement emerging technologies (e.g., streaming platforms, graph databases, ML pipelines) to improve data capabilities. Mentorship & Technical Oversight Provide technical leadership and mentorship to junior engineers and analysts, fostering a culture of excellence, learning, and continuous improvement. Review code, enforce best practices, and ensure … measures. Maintain documentation and knowledge repositories to support operational continuity and onboarding. Profile Master's or Bachelor's degree in Computer Science, Data Engineering, Applied Mathematics, or a related technical field. 8+ years of experience in data engineering, with at least 3 years in a senior or lead role. Proven experience in the energy trading sector, ideally with exposure More ❯
Employment Type: Permanent
Salary: GBP Annual
Posted:

Senior Staff Software Engineer

London, United Kingdom
JDA Software
development, and implementation of our Returns Drop-off Kiosk solutions at Blue Yonder, as it prepares to scale. The role will focus on planning and facilitating the direction of technical work. You will provide technical leadership and act as line manager for a high-performing team, mentoring team members daily, and helping shape and maintain our engineering … an individual contributor. What you'll do: Support the design and development of applications across the entire stack, from database to user interface. Architect scalable, maintainable solutions that balance technical excellence with business needs. Drive technical decision-making and strategy. Establish coding standards, best practices, and technical documentation. Provide mentorship and technical guidance to other engineers. … Collaborate with product management to refine requirements and technical specifications regularly. Identify and resolve performance bottlenecks and technical debt. Evaluate and recommend new technologies and patterns to improve our development ecosystem. Participate in architectural decisions and contribute to long-term technical strategy within the Technical Architecture Group (TAG). What we are looking for: Required Skills More ❯
Employment Type: Permanent
Salary: GBP Annual
Posted:

Senior Software Engineer - C# / FinTech

London, South East, England, United Kingdom
Hybrid / WFH Options
Connexa
infrastructure, and AI technologies, contributing to the business' ongoing digital evolution. Main Purpose of the Role:Lead backend development and play a key role in the mobile app delivery.Drive technical innovation and work across multiple high-profile projects.Collaborate closely with Developers, Data Engineers, Product Managers, and Technology Specialists. Key Responsibilities:Design, develop, and maintain scalable, secure, and high-quality … backend connectivity.Incorporate AI technologies and models where applicable to enhance software capabilities.Promote coding best practices, automated testing, and continuous improvement.Collaborate with cross-functional teams to translate business requirements into technical solutions.Manage multiple projects simultaneously within a fast-paced FinTech environment. What They Are Looking For:7+ years of senior-level software development experience.Deep commercial experience with C# development.Strong knowledge … CD pipeline development and deployment automation.Experience contributing to mobile app development projects.Keen interest and practical experience in AI technologies and their application within software development.Excellent problem-solving abilities and technical leadership skills.Highly adaptable, able to thrive in fast-moving and ambiguous environments.Strong collaboration, communication, and stakeholder engagement skills.Degree qualified in Computer Science, Engineering or related discipline.Comfortable with hybrid More ❯
Employment Type: Full-Time
Salary: £100,000 - £110,000 per annum
Posted:

Principal Platform Engineer

London, United Kingdom
Institutional Shareholder Services Inc
type Full time posted on Posted 4 Days Ago job requisition id JR_8684 Let's be ISS Stoxx is seeking a Principal Platform Engineer to bring expert-level technical leadership to the development and deployment of our cutting-edge financial intelligence platform. We are in the early stages of a full-scale re-architecting of our on … and evolve our platform architecture and interpret requirements and enterprise policies into requirements that deliver clear value. You'll be an advocate of our platform architecture and solutions, demonstrating technical principles and business value. You'll be able to demonstrate comfort and success in a matrixed organisation where reporting lines do not dictate technical direction - in a culture More ❯
Employment Type: Permanent
Salary: GBP Annual
Posted:

AI Cloud Solution Architect

London, United Kingdom
Hybrid / WFH Options
Curo Resourcing Ltd
integrations, and driving forward both client success and internal AI accelerators. Key Responsibilities: Design scalable, secure Azure AI architectures tailored to client needs. Work closely with customer business and technical stakeholders. Define and deliver solutions involving RAG systems, Agentic AI, knowledge bases, and MCP integrations. Lead pre-sales engagements including PoCs, workshops, and stakeholder briefings. Collaborate with engineers, analysts … and security. Monitor performance and optimise ongoing AI solutions. Contribute to internal AI accelerators and communities of practice. Stay ahead of AI trends and emerging technologies. Mentor and provide Technical Leadership. Participate in the business's internal communities. Requirements: A strong grasp of Microsoft Azure and Generative AI solutions, from envisioning through to engineering, evaluation and evergreening. An Azure More ❯
Employment Type: Permanent
Salary: GBP Annual
Posted:

Lead Full Stack Engineer

City of London, London, United Kingdom
Lynx Recruitment
A leading AWS Premier Consulting Partner is seeking a Lead Full Stack Engineer to join its growing technical team. As a key member of this cloud-native consultancy, you'll work on innovative digital solutions for a diverse range of clients – from fast-growing start-ups to established enterprises. You’ll bring technical leadership, strong coding skills … and a proactive approach to delivering secure, scalable applications using AWS technologies. Key Responsibilities Technical Leadership Guide and mentor junior developers within the team. Lead architecture design and technical planning discussions. Ensure coding standards, security best practices, and high-quality code reviews. Promote continuous improvement in development practices and processes. Advocate for a “security by design” mindset … React , and TypeScript . Strong foundation in Agile/Lean methodologies and modern software delivery practices. Working knowledge of UI/UX principles and prototyping tools. Excellent communication and technical writing skills. Strong problem-solving abilities and a passion for innovation. Bachelor’s degree (2:1 or above) in Computer Science or related field. More ❯
Posted:

Lead Full Stack Engineer

London Area, United Kingdom
Lynx Recruitment
A leading AWS Premier Consulting Partner is seeking a Lead Full Stack Engineer to join its growing technical team. As a key member of this cloud-native consultancy, you'll work on innovative digital solutions for a diverse range of clients – from fast-growing start-ups to established enterprises. You’ll bring technical leadership, strong coding skills … and a proactive approach to delivering secure, scalable applications using AWS technologies. Key Responsibilities Technical Leadership Guide and mentor junior developers within the team. Lead architecture design and technical planning discussions. Ensure coding standards, security best practices, and high-quality code reviews. Promote continuous improvement in development practices and processes. Advocate for a “security by design” mindset … React , and TypeScript . Strong foundation in Agile/Lean methodologies and modern software delivery practices. Working knowledge of UI/UX principles and prototyping tools. Excellent communication and technical writing skills. Strong problem-solving abilities and a passion for innovation. Bachelor’s degree (2:1 or above) in Computer Science or related field. More ❯
Posted:

Lead Full Stack Engineer

South West London, London, United Kingdom
Lynx Recruitment Limited
A leading AWS Premier Consulting Partner is seeking a Lead Full Stack Engineer to join its growing technical team. As a key member of this cloud-native consultancy, you'll work on innovative digital solutions for a diverse range of clients from fast-growing start-ups to established enterprises. Youll bring technical leadership, strong coding skills, and … a proactive approach to delivering secure, scalable applications using AWS technologies. Key Responsibilities Technical Leadership Guide and mentor junior developers within the team. Lead architecture design and technical planning discussions. Ensure coding standards, security best practices, and high-quality code reviews. Promote continuous improvement in development practices and processes. Advocate for a security by design mindset in … React , and TypeScript . Strong foundation in Agile/Lean methodologies and modern software delivery practices. Working knowledge of UI/UX principles and prototyping tools. Excellent communication and technical writing skills. Strong problem-solving abilities and a passion for innovation. Bachelors degree (2:1 or above) in Computer Science or related field. More ❯
Employment Type: Permanent
Posted:

Senior Kotlin Developer

London, United Kingdom
Hybrid / WFH Options
Halian Technology Limited
Senior Kotlin Developer to join their expanding digital engineering function. This position requires deep expertise in Kotlin or modern Java , strong architectural understanding of microservices , and a passion for technical leadership and mentoring. Experience working within ecommerce, mobile, or customer-facing digital platforms is highly desirable. This role is a remote position. Youll have the opportunity to work … product teams, and contribute to a high-traffic platform used by millions of customers. Key Responsibilities: Design, build, and maintain scalable, high-performance services using Kotlin or Java Provide technical leadership and mentoring to other engineers in the team Contribute to solution architecture and strategic technical direction Build, integrate, and maintain REST APIs and backend services Champion More ❯
Employment Type: Permanent, Work From Home
Salary: £90,000
Posted:

Lead Staff Software Engineer

London, United Kingdom
The Trade Desk, Inc
locations - London, UK and CO, US (Denver and Boulder). What you'll do: It's the best of both worlds-you'll get a chance to exercise your technical leadership and build up your people management and leadership skills. Within the charter of the team, some of the work that you will be doing to help … us deliver on our mission is: Technical leadership: • Actively review design and code. • Deliver meaningful technical and hands-on contributions to the team's objectives. • Understand strategic business priorities and how the team's charter impacts those, and communicate with the team on how their work fits into the roadmap. Project level processes and execution: • Collaborate with … and optimize team efficiency. • Establish and deliver on team commitments. • Measure and maintain/improve the quality of the team's contributions. • Communicate important developments and changes to area leadership and other stakeholders. People management: • Manage a small team. • Help team members develop career growth plans. • Give regular and effective feedback. • Hold weekly 1:1 meetings with direct reports. More ❯
Employment Type: Permanent
Salary: GBP Annual
Posted:
Technical Leadership
London
10th Percentile
£63,750
25th Percentile
£85,000
Median
£97,500
75th Percentile
£115,000
90th Percentile
£122,500