Libor Martinek
Verified Expert in Engineering
Python Back-end Developer
Brno, South Moravian Region, Czech Republic
Toptal member since March 11, 2022
Libor is a Python back-end developer with over 8 years of experience who has built several applications for data processing, cybersecurity, and cryptocurrencies. He proposes, implements, and deploys solutions, owns them end-to-end, and is dedicated to his craft. He enjoys mentoring other developers. Libor's commercial experience is backed by a bachelor's degree in mathematics and physics.
Portfolio
Experience
- Python - 6 years
- Linux - 6 years
- Docker Compose - 5 years
- Functional Programming - 5 years
- SQL - 5 years
- PostgreSQL - 5 years
- Pytest - 5 years
- Docker - 5 years
Work Experience
Senior Back-end Engineer
SandboxAQ
- Developed an application for use by in-house scientists as a source of truth that catalogs chemical compounds and tracks their appearance in experiments launched as part of internal data pipelines.
- Proposed, designed, and carried out a database migration from an inefficient Neo4j to AlloyDB. Outcomes were much better, with cross-tenant data isolation, easier operations and maintenance, and a significant increase in query performance.
- Championed a testing strategy that runs against real deployment and in parallel with data closely matching reality. This led to many concurrency bugs being discovered and fixed, thereby strengthening trust in the system tremendously.
- Conducted very thorough code reviews on a regular basis, which oftentimes uncovered errors and bugs. These reviews also served as grounds for mentorship and for deepening understanding of the system.
Senior Software Developer
SandboxAQ
- Developed an application for use by in-house scientists as a source of truth that catalogs chemical compounds and tracks their appearance in experiments launched as part of internal data pipelines.
- Championed a testing strategy that runs against real deployment and in parallel with data closely matching reality. This led to many concurrency bugs being discovered and fixed, thereby strengthening trust in the system tremendously.
- Instrumented an automatic performance tracing of the application endpoints that led to discoveries of bottlenecks and inefficient database queries. Fixes improved stability and performance by several orders of magnitude.
- Spearheaded an initiative that led to the switch of the database engine, which did not require application downtime. This switch helped tremendously with sensitive data segregation, insufficient transaction isolation protections, and performance.
Back-end Software Developer (via Toptal)
SandboxAQ
- Developed a network traffic analyzer and an agent-based solution that captured traffic on a host machine, which could send the data to the back-end server for further soft real-time analysis.
- Led the efforts of introducing a means for increasing observability of the whole platform, including cross-correlation of distributed requests and performance monitoring.
- Conducted application and database profiling. Based on the results, I spearheaded the effort of optimizing the back-end server by several orders of magnitude.
- Created a suite of SQL scripts used for migrating all the data owned by a customer from a multi-tenant database to a dedicated instance just for them.
- Participated in several crises where resolution of the customer's asks was necessary as soon as possible, during which my proposed solutions and implementations were carried through to success.
Python Mentor
Software Development Academy
- Mentored aspiring students on their Python programming journey.
- Created interactive study materials for students' self-paced learning.
- Assisted students with their first real-world application development.
Back-end Developer
Crypkit
- Developed an app for managing and aggregating a cryptocurrency portfolio of an investment fund or a single user.
- Integrated 3rd-party APIs via providers or directly through specific cryptocurrency nodes.
- Evaluated cryptocurrency projects and APIs, prioritized their subsequent integration, and oversaw or directly implemented the solutions.
Back-end Developer
Braiins Systems
- Transitioned the project from a Python 2 to a Python 3 codebase.
- Maintained various cryptocurrency node clients and implemented new API methods.
- Implemented a system to monitor the duration of a user request and its subsequent analysis.
Back-end Developer
Blindspot Solutions
- Developed an application that aids security analysts during a security incident investigation.
- Handled client feature requests and was actively involved in the design specification and subsequent implementation.
- Implemented a testing infrastructure for performance checking and regression detection.
Project History
Bitcoin Node RPC Client
https://github.com/bibajz/bitcoin-python-async-rpcAedificator
https://github.com/bibajz/aedificatorDatabase Transaction Modelling via Dependent State Machines
It's more of a research project; the goal is to have the model first and then try to run it against a real database.
Education
Bachelor's Degree in Mathematics and Physics
Czech Technical University - Prague, Czech Republic
Certifications
Advanced Modeling for Discrete Optimization
The University of Melbourne | via Coursera
Cryptography I
Stanford University | via Coursera
Skills
Libraries/APIs
REST APIs, Asyncio, Flask-RESTful, SQLAlchemy, Sockets, GraphQL API, Pydantic, API Development
Tools
GitLab CI/CD, Docker Compose, Git, Pytest, Makefile, Terraform, RabbitMQ, Bazel, Vagrant, Wireshark, Tcpdump, Grafana, Shell, CircleCI, BigQuery
Languages
Python, Python 3, SQL, Scheme, Bash Script, Bash, GraphQL, MiniZinc, Idris
Frameworks
Flask, Django
Paradigms
Functional Programming, Test-driven Development (TDD), DevOps, Automation, Event-driven Programming, Concurrent Programming, Database Design, ETL
Platforms
Docker, Linux, Amazon Web Services (AWS), Jupyter Notebook, Rancher, Debian, Google Cloud Platform (GCP)
Storage
PostgreSQL, InfluxDB, Redis, ArangoDB, JSON, NoSQL, Neo4j, SQL Performance, Database Modeling, Google Cloud, Data Validation, Data Pipelines, Database Architecture, Database Performance, Graph Databases
Other
Bitcoin, Property-based Testing, CI/CD Pipelines, HTTP, NeoVim Text Editor, APIs, FastAPI, Middleware, Version Control, Sanic Web Server, Async/Await, Podman, SSH, Prometheus, Optimization, TCP/IP, Transport Layer Security (TLS), Shell Scripting, OpenTelemetry, Cryptography, Discrete Optimization, Back-end, Trading, API Integration, WebSockets, Multiprocessing, Distributed Tracing, Structured Logging, Temporal, Code Review, Data Modeling, AlloyDB, Multi-tenant Architecture, Dependent Type Theory, Transactions, State Machines, Query Optimization, Database Schema Design, Data Engineering, Google BigQuery, Database Optimization, Architecture, Graph Query Language (GQL), Data Architecture
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