Máté Marjai

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Máté Marjai

Founder-minded engineering leader with 15+ years building products and teams from 0 to 1 — twice as seed-stage CTO, and across fintech companies that collectively serve hundreds of thousands of merchants. Deep expertise in payment infrastructure, mobile and web SDKs, and cloud architecture. Proven track record scaling teams of up to 30 engineers through B2C-to-B2B pivots, rapid international expansion, and cross-functional organisational change. Active international speaker and community builder across the functional programming and payments ecosystems.

Engineering Manager at Primer

Feb 2024 -

Key Achievements

Leading the Acceptance Experience Team at a Series B payments company, owning the full mobile and web SDK surface that powers checkout for merchants globally. 9 direct reports across iOS, Android, and Web, operating across mobile and web platform guilds.

  • Active part in the reorganisation to cross-functional teams
  • Fostered AI initiatives within the team as well as org-wide
  • Spearhead engineering wide initiatives like incident fire drills, mentorship programme, engineering blog and team-wide demos
  • Checkout SDK rearchitecture across the board (iOS, Android and Web) with a component based approach
  • Driving IC Growth plans and mentoring Senior and Staff engineers
  • Improved SDK conversion rate, enabling all merchants to view and act on conversion data directly from the SDK
  • Reduced SDK integration time from weeks to days, accelerating merchant time-to-value
  • Delivered 10x increase in design token and component customisation options, expanding the addressable merchant segment
  • Rearchitected payment timeline API reliability, reducing escalation and support ticket resolution time to one-tenth of previous baseline

Engineering Manager at Phorest

Nov 2021 - Feb 2024

Key Achievements

Leading the Ecommerce Team (8 direct reports), responsible for client facing Online Booking, Retail, Voucher services and Branded Apps in Phorest Salon Software - a major Beauty industry SAAS product

  • Personal and team career goalsetting and mentoring
  • Introduced KanBan methodology reducing cycle time by 40% and improving delivery predictability from 60% to 85%
  • Working with Senior Leadership and Product teams on technical and product roadmaps around Online Booking rearchitecture from multiple repos to React monorepo
  • Co-Founding grassroots org-wide initiatives, like the Quarterly Shoutout.

CTO & Co-founder at BonsaiX (seed stage, 0→1)

July 2020 - Feb 2023

Key Achievements

Built and shipped a knowledge management product from zero, owning the full technical remit alongside co-founder responsibilities: product strategy, fundraising conversations, headcount planning, and direct customer engagement.

  • Recruited and led engineering team of 6 from 0, establishing engineering culture and technical standards
  • Drove two flagship integrations — powering knowledge infrastructure for Budapest Go (Hungary's largest transport app) and MVM's national solar panel FAQ rollout
  • Partnered with co-founders on product strategy, go-to-market planning, and fundraising conversations
  • Architected cloud infrastructure achieving 99.9% uptime with zero-touch deployments
  • Designed analytics infrastructure providing real-time insights to sales and customer success teams
  • Managed technical budget including cloud infrastructure, tools, and vendors

Senior DevOps Specialist at CleverCards - contract

May 2019 - Oct 2021

Key Achievements

Operations and Architecture for CleverGift platform

  • Rehaul the full architecture of CleverGift in AWS, with +50% saving in the monthly bills in the process.
  • Reporting infrastructure: Architect a cloud-based, serverless solution to manage data flow between main Databases and a central reporting Database
  • E-Gift Cards: Whitelabel solution for partners of CleverGift. Design and lead the mobile and external API to be used by partners.
  • Corporate ordering: Portal Architecture & 3rd party integrations
  • MasterCard MPTS service integration for virtual card issuing

Engineering Director at ThePayment.Works

June 2016 - June 2020

Key Achievements

Technical leader for payments software toolkits serving fintech clients including CleverCards and EuroSEPA. Responsible for system architecture, high-availability design, and whitelabel product strategy. Led a team of up to 4 engineers.

  • Created and led Testing Pays — a payment integration testing platform — from concept to product, owning technical direction, team building, and product roadmap
  • Served as embedded engineering director for fintech clients, delivering payment infrastructure and integration tooling used in production by financial institutions
  • Architected whitelabel payment solutions enabling clients to launch branded payment products without building core infrastructure
  • Managed client relationships end-to-end, from technical discovery through delivery and ongoing operations

Engineering Director at TheProduct.Works

August 2014 - June 2020

Key Achievements

Founded and led software technology consultancy providing senior engineering leadership to fintech, healthtech, and financial services clients. Managed end-to-end client relationships from discovery through delivery.

  • Create and operate SMART App - community midwife planner
  • Grammofy - Classical music streaming.
  • EuroSEPA - Online invoice exchange and electronic payments for business.
  • Linked Finance - Peer-to-peer lending.
  • SAM Booking - language school booking engine between agents and schools.

CTO at Popdeem (seed stage, 0→1)

August 2014 - October 2015

Key Achievements

Seed-stage CTO leading the technical transformation from a direct B2C consumer product to a B2B self-serve platform. Reported directly to CEO, co-owned the product roadmap alongside CPO, and participated in business and investor meetings. Led a team of 4 engineers.

  • Pivoted the product from a consumer coupon and content tool on Facebook to a B2B platform giving businesses direct control over campaign creation and management
  • Owned full product roadmap in partnership with CPO and CEO, with direct influence on business strategy and go-to-market decisions
  • Built and led engineering team from the ground up, establishing technical standards and delivery culture

Lead Software Engineer, Acceptance and Payments team at SumUp

January 2014 - June 2014

Key Achievements

Leading the project to deliver Pin+ - state of the art Chip and PIN solution for SMBs. Working with hardware engineering closely in the integration phase of Pin+ to bring it into production. Turning the product from early prototype phase into production ready state. Creating a delivery focused culture and advocate continuous delivery. Support the device and system certification process: GICC - EMV payments, MTIP - MasterCard, ADTV - Visa, Visa Live tests.

Senior Software Engineer, Experience and Payments team at SumUp

January 2012 - January 2014

Key Achievements

Built the Dublin Software Team from 0 to 15 engineers at SumUp's inception. Working directly with SumUp's founders, designed and delivered the core API and surrounding platform. Led the team to launch self-serve merchant sign-ups across 10 countries within the first year, going from 0 to hundreds of active merchants. Working closely with SysOps on bootstrapping deployment processes. Delivered and maintained internal admin interface for Customer Service, Payment Operations, and AML.

Created DSL to describe onboarding flows that can be controlled from the backend on all signup channels (web, iOS, Android). Creating early prototypes for our award winning 'customer app' proof of concept. Creating the SumUp app-switch API. Receipt delivery and printing R&D.

Software Developer, Web and Mobile team at Hostelworld

January 2011 - January 2012

Key Achievements

Creating critical features for the business working on Hostelworld's flagship site and internal admin. Conduct the migration from Bugzilla to Jira. Exploring and advocating new ways of enhancing the delivery tools used. Piloting agile workflows with key members of the organisation.

Enhancing our mobile presense on dedicated site and mobile app. Conduct code migration from JS to CoffeeScript. Delivering v1.0 of our cross platform mobile app on iOS and Android using the mobile site as a base. Reorganise the backend APIs used for mobile and external services for payments, bookings and account details.

Web Developer, Cashier team, Payments at Full Tilt Poker

November 2008 – January 2011

Key Achievements

Delivered and supported over 50 projects of various complexity, all of which were mission critical for the business. Most notable ones include: Single click deposit, Cancel withrawal, Targeted marketing messages, Flexible player limits. Designed and delivered analytics and monitoring tools for our production systems. Slimmed down our deployment process from a 25-step list into a single click solution.

Web Developer/Co-Owner - Szoftver Szerviz Iroda

February 2006 – April 2008

Helping small businesses with invoicing and accounting solutions. Web solutions consulting for small businesses (HTML, PHP, Javascript, web hosting)


Community

Organizer of Erlang & Elixir meetup, Dublin

Co-Host of Functional Kubs, Dublin

Coach @ Rails Girls, Galway & Dublin

Graduate coach @ Progmasters, Budapest


Talks & workshops

Don't let it crash! - Erlang OTP workshop, CodeMesh, London

Building the largest payment sandbox on a tiny machine, CUFP

Building resilient systems for high traffic - Erlang OTP workshop, Big Data Vilnius

Elixir on its best behaviour - workshop, ElixirConf EU

Elixir Katas workshop & "Managing High Load on Low Budget" presentation, Big Data Moscow

Elixir Katas workshop, CodeMesh


Studies and qualifications

BSc in Computer Science, Eötvös Loránd University, Faculty of Informatics, Budapest


Key Strengths

Leadership: Team building & hiring, engineering culture, IC growth & mentorship, cross-functional influence, headcount planning, seed-stage 0→1, team topologies

Domain: Payments infrastructure, mobile & web SDKs (iOS, Android, Web), cloud architecture & DevOps, high-availability systems

Technical: Elixir, Erlang, Ruby, JavaScript, React, PostgreSQL, AWS, Azure, Python

Methods: Agile, Kanban, CI/CD, TDD, incident management, engineering metrics