Jano Suchal, Software Developer in Bratislava, Bratislava Region, Slovakia
Jano Suchal

Software Developer in Bratislava, Bratislava Region, Slovakia

Member since March 24, 2014
Jano is a full-stack developer with strong database skills and a passion for clean code. He handles performance tuning for back-ends and enhances usability in front-ends. He has a serious background in machine learning, recommendation systems, and search.
Jano is now available for hire


  • Slovensko.Digital
    Amazon Web Services (AWS), AWS, Jira, PostgreSQL, Elasticsearch...
  • Minio
    JavaScript, Redis, Elasticsearch, PostgreSQL, Ruby on Rails (RoR)
  • SearchD/Luigi's Box
    SaltStack, PostgreSQL, Redis, Elasticsearch, Ruby on Rails (RoR)



Bratislava, Bratislava Region, Slovakia



Preferred Environment

Git, RubyMine, Linux

The most amazing...

...things I've coded are sites using public data in Slovakia, making government contracts and company registers more transparent.


  • Lead Developer and Project Manager

    2015 - PRESENT
    • Led a small team of developers and freelancers to build parallel, low-cost e-government services.
    • Created a platform for downloading/cleaning public open data sets with millions of entries and gigabytes of data.
    • Built a fast autocomplete search based on Elasticsearch.
    • Managed multiple servers serving staging/production environments with Docker-based deployment.
    • Supported various tools needed for business (Trello, Jira, email servers, billing, AWS).
    Technologies: Amazon Web Services (AWS), AWS, Jira, PostgreSQL, Elasticsearch, Ruby on Rails (RoR), Redis
  • Owner

    2011 - PRESENT
    • Created a platform for scraping various public government registers and databases.
    • Built a platform for automatic data disambiguation, cleaning, and reconciliation of multiple messy public datasets.
    • Managed traffic/performance analytics for several projects.
    • Built a platform for making government contracts transparently available for anyone in Slovakia.
    • Managed a search engine with 600K+ documents (TBs of raw data).
    • Organized a monthly polyglot developer meet-up in Bratislava every month since 2011.
    • Created a system for fraud detection in European Social Fund project proposals.
    Technologies: JavaScript, Redis, Elasticsearch, PostgreSQL, Ruby on Rails (RoR)
  • Senior Developer

    2013 - 2015
    SearchD/Luigi's Box
    • Created a scalable log processing pipeline analyzing millions of events.
    • Designed advanced metrics and reports for testing and evaluation of real-world search engines.
    • Contributed to the full stack—from business goals through front-end tuning to back-end development and tuning.
    • Ensured high code quality by enforcing automatic testing on the build server, code coverage trend reporting, and code reviews.
    • Proposed and successfully implemented business process changes to optimize signup and onboarding funnels, yielding an increase in goal conversions.
    Technologies: SaltStack, PostgreSQL, Redis, Elasticsearch, Ruby on Rails (RoR)
  • Senior Back-end Developer

    2011 - 2013
    • Created a recommendation engine for movies and television shows.
    • Built a logging and quality evaluation platform for a recommendation engine and search-related sub-projects.
    • Proposed and measured several UX enhancements on user-facing pages.
    • Created a crawling service scraping data from various online sources.
    • Implemented various duplicate matching algorithms for cleaning and disambiguating data.
    Technologies: PostgreSQL, Redis, Elasticsearch, Ruby on Rails (RoR)
  • Founder

    2010 - 2012
    • Created and sold a project to download, clean, and update data about over 300,000 companies and 500,000 people from the official registers of Slovak companies, public procurement, debts, internet domains, and other public data.
    • Supported a complex site handling over 500,000 page views a month.
    • Created a framework for scraping, cleaning, and merging messy datasets.
    • Built various visualizations and aggregation reports from gathered data.
    • Fine-tuned autocomplete search for highly relevant instant responses.
    Technologies: Sphinx Search Engine, MySQL, Ruby on Rails (RoR)
  • Researcher | PhD Student

    2008 - 2011
    Faculty of Informatics and Information Technologies
    • Built a news recommendation engine for the largest Slovak newspaper peaking at 3,000+ rpm.
    • Created and led a new course on full-stack web development.
    • Published multiple articles on recommendation systems and data mining.
    • Led multiple teams of students on various projects.
    • Built and supported various faculty websites and apps.
    Technologies: SQL, R, Ruby on Rails (RoR), Ruby
  • Contractor

    2001 - 2011
    • Built a "did you mean?" search feature for a major music website in Slovakia.
    • Built and maintained web applications for various SMEs.
    • Consulted several clients regarding SQL performance fine-tuning.
    • Created a popular random text generator for designers.
    • Handled basic HTML/CSS work for various clients in the eCommerce sector.
    Technologies: PostgreSQL, MySQL, JavaScript, Ruby on Rails (RoR), PHP


  • SynopsiTV

    Movie and TV show recommendation system and social site.

  • Open Contracts

    A crowdsourcing platform for searching and analyzing government contracts. It provides a much more usable interface to work with contracts of Slovak governmental organizations in comparison to the official government site. It downloads and processes over 300k scanned documents (over 1TB of raw data) in various formats from many sources and transforms them into an easily searchable format using full text and advanced faceted search. Contracts are automatically analyzed and assigned a score indicating how problematic the contract is. This analysis is based on the rules managed by portal administrators.

  • Social Network of Slovak Companies

    This site downloads, cleans, and updates data about over 300k companies and 500k people from official registers of Slovak companies, public procurements, debts, internet domains, and other public data. It shows all current and historic data about companies in an aggregated and usable form. It visualizes connections of people and companies as network (graphs) for deeper insights. It is used heavily by the public and private sector and handles traffic of over 500k page views per month.

  • API for All Slovak Government Data

    An API for retrieving cleaned, reconciled, and merged data scraped from various public datasets and registers.

  • SearchD/Luigis's Box

    Search analytics platform collecting and evaluating millions of events in real time.

  • Fraud Detection in European Social Fund Project Proposals

    This crawls a legacy internal project management system and collects data about projects. It features enrichment of this data from other external sources: Slovak company register, register of NGOs, and the statistical office of the Slovak Republic. It involves extensive data cleaning, reverse duplication routines, and heuristics to match and distinguish subjects.

    It identifies conflicts of interests between various stakeholders of the project by analyzing relationships within data.

  • Garelic

    A Google Analytics gem for Rails app performance.


  • Languages

    Ruby, SQL, PHP, JavaScript, R, CoffeeScript
  • Frameworks

    Ruby on Rails (RoR), Sinatra
  • Paradigms

    Agile Software Development, Test-driven Development (TDD), Object-oriented Design (OOD), Behavior-driven Development (BDD), Dependency Injection
  • Platforms

    Salesforce, Linux, Amazon Web Services (AWS)
  • Storage

    Elasticsearch, Redis, PostgreSQL, MySQL, Sphinx Search Engine
  • Other

    Machine Learning, Recommendation Systems, AWS
  • Libraries/APIs

    Twitter API, Facebook API, jQuery, GitHub API
  • Tools

    SaltStack, Jira, Git, GitHub, RubyMine


  • PhD (Unfinished) Degree in Machine learning
    2007 - 2011
    Slovak University of Technology - Bratislava
  • Master's (Summa Cum Laude) Degree in Software Engineering
    2005 - 2007
    Slovak University of Technology - Bratislava
  • Bachelor's Degree in Informatics
    2001 - 2005
    Slovak University of Technology - Bratislava

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