Josef is currently unavailable
Josef Toman
Verified Expert in Engineering
Software Developer
Dobřichovice, Central Bohemian Region, Czech Republic
Toptal member since March 31, 2021
Bio
Josef is a broadly skilled developer with over a decade of professional experience, strong theoretical background, the capacity to quickly learn anything given enough documentation, and a passion for programming since childhood. His recent endeavors mainly included creating automated data pipelines and tools leveraging the acquired data. Josef cares deeply for a client's actual needs and has an eye for security, long-term stability, and maintainability.
Portfolio
Freelance Clients
Vue, PHP, Python, NGINX, JavaScript, HTML, CSS, Amazon Web Services (AWS), Bash...
Cogvio
Database Design, Automation, Web Scraping, Amazon Web Services (AWS)...
Yeseter
Perl, C, PostgreSQL, Elasticsearch, CouchDB, MySQL, MongoDB, Web Scraping, Bash...
Experience
- Database Design - 12 years
- PostgreSQL - 12 years
- Automation - 11 years
- JavaScript - 10 years
- Web Scraping - 10 years
- Elasticsearch - 6 years
- Amazon Web Services (AWS) - 5 years
- Python - 5 years
Preferred Environment
Linux, Vim Text Editor, Slack, GitLab, Trello, Amazon Web Services (AWS), PostgreSQL
The most amazing...
...thing I've created is the automated monitoring of real estate offers. It helped me find a home for my family, and I turned it into a profit-generating service.
Work Experience
Developer
2012 - PRESENT
Freelance Clients
- Developed a successful prototype of an event-driven simulation to model drug prices in the European Union. The prototype was integrated with Google Sheets to fulfill initial needs. Later, it was used as a basis for further in-house development.
- Assisted a team of analysts in creating a set of complex research reports by developing a framework for coding simple modules ("chapters") and providing ongoing support whenever necessary.
- Developed a front-end application for scheduling minute-by-minute factory production using streamlined drag-and-drop actions. Achieved real-time optimized reactions to dragging in an environment with various logical constraints.
- Developed a contact scraping tool. The input was a set of companies and their websites. The scraper should hop through the website and collect management contact information.
Technologies: Vue, PHP, Python, NGINX, JavaScript, HTML, CSS, Amazon Web Services (AWS), Bash, Web Scraping, Git, Linux, Elasticsearch, GitLab, Automation, Object-oriented Programming (OOP), Sentry, Data Engineering, Data Modeling, Databases, ETL, ELT, AWS Lambda, Event-driven Programming, APIs, Scraping, REST APIs, Data Extraction, Scripting, JSON, Data Scraping
Data Engineer
2017 - 2021
Cogvio
- Developed a set of AWS Lambda functions containing web scrapers, ETL jobs, and reporting tools. These AWS Lambda functions were interconnected in a fully automated system that could deliver a report to a customer shortly after new data became available.
- Designed an advanced full-text search model for Elasticsearch based on analyzing thousands of search queries. The improved full-text featured specialized domain-specific capabilities, greatly enhancing the user's experience.
- Designed and maintained a PostgreSQL database instance with multiple schemas, a hierarchical system of roles, and granular privileges for all users, including admins, developers, analysts, and automated processes.
- Developed an automated service for scraping tables from PDF files using Amazon Textract. The service was configurable with Google Sheet data and included a Slack integration.
Technologies: Database Design, Automation, Web Scraping, Amazon Web Services (AWS), PostgreSQL, Elasticsearch, Python, Bash, Scripting, Linux, Git, Data Engineering, ETL, REST APIs, Docker, Scraping, APIs, Data Modeling, AWS Lambda, SQL, GitLab, Amazon S3 (AWS S3), Terraform, JSON, Data Scraping
Lead Back-end Developer
2012 - 2017
Yeseter
- Led the redesign of a complex Elasticsearch data model with millions of documents resulting in a 10x-100x speed increase while using 30%-50% of original resources.
- Developed a web scraping methodology and guidelines for junior developers.
- Created a system autonomously discovering Facebook profiles/pages within selected countries, evaluating their influence, and efficiently reading published posts and comments.
- Increased the number of daily acquired documents (articles, blog posts, comments, chat messages, and so on) from tens of thousands to more than a million.
Technologies: Perl, C, PostgreSQL, Elasticsearch, CouchDB, MySQL, MongoDB, Web Scraping, Bash, Git, Automation, Linux, NGINX, Database Design, Object-oriented Programming (OOP), Data Engineering, Data Modeling, Databases, ETL, Event-driven Programming, APIs, Scraping, REST APIs, Data Extraction, Scripting, Data Science, JSON, Data Scraping
Technical Specialist
2010 - 2012
Institute of Formal and Applied Linguistics, Charles University
- Improved the visualization of a single dependency parse tree and created a new visualization showing related and interlinked parse trees alongside each other with a configurable layout.
- Built two types of in-browser visualization of language corpora using pure HTML5: one automatically aligned audio recordings with multiple manual transcriptions and the second interactively linked related parse trees with tree nodes and source text.
- Created automated processes to release several language corpora: data acquisition from multiple Git repositories, templates for technical writers, a static website build localized to two languages, and data transformation.
Technologies: Perl, Bash, JavaScript, HTML, CSS, Linux, Data Engineering, ETL, Data Extraction, Scripting, JSON
Full-stack Developer
2009 - 2010
Winternet
- Developed a new control panel for a web hosting provider, including domain registration and renewal, mail server management, database provisioning, and invoicing.
- Built a pluggable submodule of a generalized in-house framework that provided a hierarchical catalog.
- Carried out a security audit of an application for an important client, identifying many security issues.
Technologies: PHP, JavaScript, HTML, CSS, MySQL, PostgreSQL, Database Design, Object-oriented Programming (OOP), Databases, APIs, Scripting, JSON
Technical Specialist
2006 - 2009
Institute of Formal and Applied Linguistics, Charles University
- Managed the data of a language corpus during its development.
- Developed tools to simplify and quicken the annotation process using automation where possible.
- Built a tool to measure the amount of work of diverse team members in a given month by computing differences in dependency parse trees committed into the project's Git repository.
- Developed an extension for the annotation tool, providing the annotator with dozens of structural checks to improve the quality and consistency of the submitted data.
Technologies: Perl, Bash, JavaScript, HTML, CSS, Linux, Data Engineering, ETL, Data Extraction, Scripting, Data Science, JSON
Experience
Framework for Automated Reporting
A team of skilled analysts with basic programming skills wanted to streamline and automate the composition of many reports (multiple variations, multiple languages) from data collected over time. The main objective was to design a system allowing the team to do as much work as possible by themselves.
I designed and implemented a framework that provides core features and allows the team to write auto-discoverable "plug-ins" (chapters, slides, QA checks). Since then, I have been providing support when necessary.
Core Features:
• CLI scripts
• Extensive YAML configuration
• ETL
• Output to DOCX, HTML, and XLSX files
• Methods for simple creation of charts and tables carefully tailored to fit the data and required use-cases
Key Characteristics:
• Stringent security and privacy measures concerning the data
• Attention to detail—every single data field must be loaded and interpreted correctly or fixed upon discovery of an error
• Very opinionated design requirements
The customer and the nature of the data are not disclosable.
I designed and implemented a framework that provides core features and allows the team to write auto-discoverable "plug-ins" (chapters, slides, QA checks). Since then, I have been providing support when necessary.
Core Features:
• CLI scripts
• Extensive YAML configuration
• ETL
• Output to DOCX, HTML, and XLSX files
• Methods for simple creation of charts and tables carefully tailored to fit the data and required use-cases
Key Characteristics:
• Stringent security and privacy measures concerning the data
• Attention to detail—every single data field must be loaded and interpreted correctly or fixed upon discovery of an error
• Very opinionated design requirements
The customer and the nature of the data are not disclosable.
Factory Production Scheduler
A Vue application for daily pre-computed production plan reviews, allowing ad-hoc manual changes.
Distinctive Features:
• 100% operable with mouse only (project requirement)
• Complex drag-and-drop actions
• A configurable mocked API to enable a full-featured experience before the actual API is implemented (random data are generated on-the-fly)
Other Contributions Besides App Development:
• Thorough initial analysis
• UX contributions
• Design based on the company's visual identity standards and consultation with a pro designer
• API design and detailed specifications
Distinctive Features:
• 100% operable with mouse only (project requirement)
• Complex drag-and-drop actions
• A configurable mocked API to enable a full-featured experience before the actual API is implemented (random data are generated on-the-fly)
Other Contributions Besides App Development:
• Thorough initial analysis
• UX contributions
• Design based on the company's visual identity standards and consultation with a pro designer
• API design and detailed specifications
EU Drug Prices Simulation
As a consultant, I developed the initial stages of an event-driven simulation to model drug prices in the European Union (EU). The EU drug market is a heavily regulated and complex system, with each country having its own rules on drug price regulations, often using prices from a set of other countries as a reference. The goal of this simulation was to model future drug prices, given a starting point, and allow users to create events in the future to see their influence on the entire system of drug prices in the EU.
The simulation was developed using Python and leveraged the Google Sheets API to input and output data. This allowed for seamless integration with existing spreadsheets and easy collaboration with stakeholders.
My client successfully used the prototype to fulfill the needs of consulting tasks for initial clients, on time and to satisfaction. Later, the prototype was used as a basis for further in-house development.
The simulation was developed using Python and leveraged the Google Sheets API to input and output data. This allowed for seamless integration with existing spreadsheets and easy collaboration with stakeholders.
My client successfully used the prototype to fulfill the needs of consulting tasks for initial clients, on time and to satisfaction. Later, the prototype was used as a basis for further in-house development.
Information System for a Tire Service Company
In a full-stack role, I developed two applications and designed a database for them.
Project Deliverables:
1. A public presentation of the company and its branches and a reservation system for customers
2. An application for the technical staff designed for touch screens (tablets) providing:
• Calendar with reservations
• A step-by-step guide navigating the staff through each service case, including SMS notifications and invoicing
Project Deliverables:
1. A public presentation of the company and its branches and a reservation system for customers
2. An application for the technical staff designed for touch screens (tablets) providing:
• Calendar with reservations
• A step-by-step guide navigating the staff through each service case, including SMS notifications and invoicing
Education
2007 - 2009
Master's Degree in Computer Science
Charles University - Prague, Czech Republic
2004 - 2007
Bachelor's Degree in Computer Science
Charles University - Prague, Czech Republic
Skills
Libraries/APIs
REST APIs, Vue, Pandas, Matplotlib, Vuex, jQuery
Tools
Slack, GitLab, Git, Vim Text Editor, Trello, NGINX, Stylus, Sentry, Google Docs, Terraform
Languages
Python, SQL, Perl, PHP, JavaScript, HTML, CSS, Bash, C
Paradigms
Database Design, ETL, Automation, Object-oriented Programming (OOP), Event-driven Programming
Platforms
AWS Lambda, Linux, Amazon Web Services (AWS), Docker
Storage
PostgreSQL, Elasticsearch, MySQL, JSON, CouchDB, SQLite, MongoDB, Databases, Amazon S3 (AWS S3), Amazon DynamoDB
Other
Web Scraping, APIs, Scraping, Data Extraction, Scripting, Data Scraping, Data Engineering, Data Modeling, Programming, Algorithms, Data Structures, Discrete Mathematics, Calculus, Probability Theory, Linear Algebra, Natural Language Processing (NLP), ELT, Generative Pre-trained Transformers (GPT), Statistics, Data Science, Amazon RDS
Collaboration That Works
How to Work with Toptal
Toptal matches you directly with global industry experts from our network in hours—not weeks or months.
1
Share your needs
Discuss your requirements and refine your scope in a call with a Toptal domain expert.
2
Choose your talent
Get a short list of expertly matched talent within 24 hours to review, interview, and choose from.
3
Start your risk-free talent trial
Work with your chosen talent on a trial basis for up to two weeks. Pay only if you decide to hire them.
Top talent is in high demand.
Start hiring