Nikolaos Kallikakis
Senior Engineering Leader
Athens
Summary
Senior Engineering Leader with 15+ years of experience scaling high-performing engineering organizations and driving technological innovation. Proven track record of implementing mission-critical payment systems, optimizing engineering operations, and reducing costs while improving delivery speed. Expert in building and leading distributed engineering teams across multiple time zones and cultures. Consistently delivered strategic initiatives resulting in significant operational efficiencies and business growth.
Overview
17
17
years of professional experience
4
4
years of post-secondary education
5
5
Certificates
2
2
Languages
Key Achievements
- Built and scaled engineering organizations from 0 to 80+ people across multiple locations
- Implemented services resulting in $20 annual million savings from reduced human labour
- Implemented PCI-DSS Level 1 payment processing platform handling peak transaction volumes of £3-4 millions
- Reduced infrastructure costs by 40% through platform consolidation
- Decreased manual test time from hours to minutes through custom in-house Java-based frameworks
Additional Information
Technical Leadership: Engineering Strategy, Agile Transformation, Cloud Architecture, Team Building, Leading distributed teams
Technologies: Java, Spring, Spring Boot, Redis, PostgreSQL, Cassandra, AWS, GCP, GraphQL, Heroku, Railway, Docker
Tracking system: monday.com, JIRA
Methodologies: Agile/Scrumban, DevOps, CI/CD, Microservices Architecture
Business: PCI-DSS Compliance, Budget Management, Strategic Planning
Work History
Sr Engineering Director
RenoFi
06.2023 - 12.2024
- Responsible for leading operations across engineering, data, QA, SRE and application support teams, overseeing a total organization of 20+ engineers
- Reduced manual testing efforts with introducing no-code test automation frameworks. Eliminated the need of spending 2-3 hours to do complete smoke tests
- Developed customized java-based process automation systems to increase testing efficiency and improve release confidence. Resulted in reducing test times from hours to minutes.
- Evaluated new technologies and tools to enhance overall system performance, stability, and security.
- Implemented cost-saving measures by centralizing multiple infrastructure platforms into Datadog resulting in approximate 40% cost reduction
- Spearheaded our "technical excellence" initiative by introducing SLOs, synthetics testing and monitoring to proactively deal with issues
Engineering Manager
Renofi
12.2021 - 05.2023
- Steered a team of up to 5 engineering leads, application support and QA, collectively managing 35+ engineers
- Improved project efficiency with strategic planning, resource allocation, and time management practices. Enabled the teams to deliver at minimum 2-3 key features on a month by month basis
- Improved incident management workflows and introduced PagerDuty to support on-call rotation
- Developed high-performing teams by providing mentorship, guidance, and opportunities for professional growth, resulting in 60% improvement in delivery velocity and 40% reduction in time-to-market
- Enhanced team collaboration through regular communication, goal setting, and performance evaluations.
- Established a culture of continuous improvement by fostering open communication channels and empowering employees to voice their ideas.
- Cultivated a positive work environment that increased employee tenure 8 out of 10 staying longer than 2 years and reduced time-to-hire from 4-5 months down to 1-2.
- Implemented innovative java based solutions to simplify and automate completely tracking end-to-end, resulting in increased productivity and streamlined operations. Reduced story tracking from 1-2 hours down to 0 since everything was automated from first commit to production deployment
Engineering Team Lead
RenoFi
05.2021 - 11.2021
- Headed a small team of back-end and front-end, provided technical guidance on projects, scaled delivery throughput and increased development efficiency.
- Tailored the engineering process, introduced agile ceremonies, whilst improving the overall quality of shipped deliverables
- Defined the overall team structure and product roadmap, which accelerated the delivery process
- Introduced monday.com to accurately track status of what is worked on, going from no visibility to full visibility and eliminating team status update meetings
Engineering Manager
Primer
02.2021 - 04.2021
- Leading engineering operations for a global automated payment ecosystem designed to optimize/simplify merchant payment flows.
- Achieved efficiency in engineering by streamlining workflows and implementing superior project management techniques.
- Directed 6 cross-functional teams (40+ engineers) in product development, ensuring specifications were met punctually.
- Enhanced recruitment process for faster hiring by utilizing various sourcing tools such as job boards, social media, and networking events.
- Introduce career path leveling.
Engineering Manager
GrubHub
10.2017 - 01.2021
- Engineering Manager for a leading online and mobile food-ordering and delivery marketplace, with the largest and most comprehensive network of restaurant partners, as well as 32 million active diners.
- Constructed a ‘Delivery Flaw Finder’ service which provided guardrails across high transactional data such as courier location pings, delivery updates, etc.. which was equivalent to millions of events during rush hour. It resulted in significantly reducing the company’s operational costs, reduced manual labour by more than 80% equivalent to approximately $20m per annum.
- Led employee relations through effective communication, coaching, training, and development.
- Conducted regular performance reviews, providing constructive feedback and coaching to facilitate continuous improvement among employees.
- Enhanced team productivity by implementing efficient workflow processes and setting clear performance expectations.
- Ensured seamless integration of Java-based applications with databases, APIs, and other systems.
- Developed team members' skills through targeted coaching sessions, resulting in improved individual performance.
- Set performance expectations for the team, monitoring progress towards goals and providing constructive feedback as needed.
- Exemplified commitment to excellence and professionalism, inspiring the team consistently.
Branch Manager/Engineering Manager
Docler Holding
05.2016 - 09.2017
- Established and scaled new technology center in Amsterdam from ground up, growing from 1 to 80+ engineers in 12 months while maintaining high quality standards and delivery velocity.
- Led key architectural decisions for livejasmin.com a top 50 visited website according to Alexa rankings with 80+ million unique monthly visitors.
- Built a digital fingerprint service handling approximately 60-80m transactions per day, ensuring data integrity and compliance.
- Coordinated with the executive team to develop and implement strategic office plans, oversaw daily office operations.
- Directed large-scale projects from inception to completion on time/budget with strict adherence to quality standards.
- Fostered an inclusive work environment by championing diversity initiatives and empowering employees at all levels as well as providing technical leadership.
- Improved engineering processes by streamlining workflows and implementing efficient project management techniques.
- Reduced project completion times by effectively prioritizing tasks and resource allocation.
- Cultivated a strong organizational culture built on integrity accountability teamwork which resulted in higher retention rates among staff.
- Increased overall company performance by implementing strategic management initiatives and streamlining operations.
Head of Development
BetVictor
02.2016 - 05.2016
- Led 3 cross-functional teams following the Spotify agile model of in total 36 people (including Devs, QA, PMs, DevOps, and AppSupport) focusing on building BetVictor's payments processing platform and re-designing the Casino product.
- Streamlined engineering processes for increased efficiency, leading to faster project completion and reduced costs.
- Managed budgets effectively while ensuring resource allocation aligned with company goals and objectives.
- Developed high-performing engineering teams through strategic hiring, focused mentoring, and performance management initiatives.
- Took ownership of assigned department-wide projects, presenting regular updates to senior leadership on progress and status.
Managing Director
BetVictor
11.2013 - 01.2016
- Kick off operations for new technology center in Budapest and provide engineering leadership.
- Implemented PCI-DSS as a Level 1 payment processor. Personally responsible for setting up a payment processing entity from ground up.
- Architected high transactional scalable systems processing 1.5+ million transactions daily with 99.999% uptime.
- Delivered consistent revenue growth by identifying new business opportunities and expanding service offerings.
- Developed comprehensive business plans, outlining long-term goals and actionable steps toward success.
- Oversaw operations and provided corrective feedback to achieve daily and long-term goals.
- Built strong teams through selective recruitment and post-hire mentorship of junior engineers.
- Evaluated emerging technologies to identify opportunities for integration into existing systems or develop innovative solutions.
- Enhanced overall team productivity with continuous training and mentoring of junior engineers.
- Optimized engineering procedures through the implementation of efficient workflow and project management techniques.
- Proactively identified and mitigated risks during project planning, ensuring smooth execution and enhanced efficiency.
- Delivered successful product outcomes by leading cross-functional teams, ensuring adherence to specifications and timeliness.
Development Team Lead
BetVictor
08.2012 - 11.2013
Senior Java Developer
BetVictor
05.2011 - 07.2012
Java Developer
Intrasoft International
05.2010 - 05.2011
Java Developer
Neurosoft
07.2008 - 04.2010
Junior Developer
Benefit Software
01.2008 - 06.2008
Education
Master of Science - Enterprise Systems Development
Brunel University
London, UK 09.2005 - 09.2006
Bachelor of Science - Computer Science
University of Bradford
Bradford, UK 09.2002 - 07.2005
Certification
IT Governance Ltd – IBITGQ Certified: PCI Implementation & Maintenance (Jul 2014)
Timeline
Sr Engineering Director
RenoFi
06.2023 - 12.2024
Engineering Manager
Renofi
12.2021 - 05.2023
Engineering Team Lead
RenoFi
05.2021 - 11.2021
Engineering Manager
Primer
02.2021 - 04.2021
Engineering Manager
GrubHub
10.2017 - 01.2021
Branch Manager/Engineering Manager
Docler Holding
05.2016 - 09.2017
Head of Development
BetVictor
02.2016 - 05.2016
IT Governance Ltd – IBITGQ Certified: PCI Implementation & Maintenance (Jul 2014)
07-2014
Managing Director
BetVictor
11.2013 - 01.2016
VMware – Certified Spring Integration Specialist
05-2013
Development Team Lead
BetVictor
08.2012 - 11.2013
VMware – Certified Spring Professional
01-2012
Senior Java Developer
BetVictor
05.2011 - 07.2012
Java Developer
Intrasoft International
05.2010 - 05.2011
Certified Java Developer
05-2010
Certified Java Developer
06-2009
Java Developer
Neurosoft
07.2008 - 04.2010
Junior Developer
Benefit Software
01.2008 - 06.2008
Master of Science - Enterprise Systems Development
Brunel University
09.2005 - 09.2006
Bachelor of Science - Computer Science
University of Bradford
09.2002 - 07.2005
Languages
Greek
Native language
English
Proficient
C2
Leadership Philosophy
- Building high-performing teams through mentorship and data-driven decision making
- Fostering inclusive, collaborative environments that drive innovation
- Balancing technical excellence with business value delivery
- Leading by example through hands-on technical leadership and active participation in solving complex challenges
- Demonstrating commitment to continuous learning and sharing knowledge across the organization
- Prioritizing team well-being and personal growth through empathetic leadership and work-life balance
- Creating psychological safety that encourages open dialogue and creative problem-solving
Hobbies
I love cooking, playing tennis and running!
Leadership Philosophy
- Building high-performing teams through mentorship and data-driven decision making
- Creating psychological safety that encourages open dialogue and creative problem-solving
- Fostering inclusive, collaborative environments that drive innovation
- Balancing technical excellence with business value delivery
- Leading by example through hands-on technical leadership and active participation in solving complex challenges
- Demonstrating commitment to continuous learning and sharing knowledge across the organization
- Prioritizing team well-being and personal growth through empathetic leadership and work-life balance
Hobbies
I love cooking, playing tennis and running!
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