My name is
Dionýz Lazar
and I'm
Senior Backend Developer (Python, Django, Flask, AWS, Heroku)
Download ResumeAbout Me
I'm an enterprising Python Backend Developer with 5 years of software engineering expertise in the design and implementation of REST APIs, web apps, AWS-specific solutions, Heroku deployments and web scraping. I have extensive experience working with startups; delivering 50+ projects to-date for clients while being Top-Rated freelancer.
Types of work you can hire me for:
• REST APIs in Python (Flask and Django-Rest-Framework)
• Web apps in Django
• AWS solutions - ECS, Lambda, EC2, S3, SES, RDS...
• Heroku deployments
• Web Scraping - scrapy, Selenium. Scraping job sites, e-commerce platforms, company directories, financial markets.
Additional skills:
• Database-related experience - PostgreSQL, Elasticsearch, Redis, MongoDB, RethinkDB, RDS
• Unit testing - CI/CD, pytest, unittest, nose
• Other experience - Docker, Git, Swagger, pandas
Client satisfaction
Skills
- Django
- Python
- Web Scraping
- Flask
- Amazon Web Services
- SQL
- Heroku
- Api
- Git
- Javascript
Testimonials
August 2019
Dionyz is a rockstar. This is the second time I've worked with him and he always delivers exceptional results. Will use him again for my next python needs!
Python Developer
July 2019
Dionyz was great, and pip-pointed the problem right away, very professional, great communication, knowledgeable and great experience to work with.
Django, python, web site speed optimization / heroku / bottlenecks / cache
July 2019
Wow, Dionyz was exceptionally fast. He did great work, and he was easy to communicate with.
Generate random text using Markov chain
November 2018
Dio's always on point and isn't just a great developer, but thinks ahead and is incredibly insightful. He did a great job of bringing all the pieces together to understand not only how to build out some of our service layer, but also how to do so efficiently. Awesome experience and would highly recommend.
Continuing work on data analysis backend systems
August 2018
Dionyz was painless, and sooooo easy to work with. Great attitude, given clear instructions which he delivered on. 10/10 I would absolutely hire him again in the future.
(Python) Need Chrome Developer tools/XHR familiar programming teacher
July 2018
Working with Dio has been a pleasure. Not only has he been able to deliver on what we're building but he's also driven some critical feedback into our overall process via automation which helps us move faster and more consistently. I couldn't be happier with the output and am definitely looking to hire him again for the next piece of work we have!
Data capture and gathering toolset for data science startup
November 2017
Very good guy, highly available; good coding abilities and skills - very versatile.
Scraping Regelleistung
November 2017
Honestly, one of the best experiences I've had. My first hire on Upwork, but I've worked in similar situations before. I'd recommend Dio to anyone who has a Python project. The first prototype was delivered within a few hours, and I was expecting at least a day or two. From there it was standard bug-hunting and OS compatibility issues. The quality of Dio's code must also be commended. I would have no qualms in hiring Dio again should a project like this one land on my desk again.
Python script to connect to Postgres database, execute a .sql file and write output to log file
September 2017
Fantastic work as usual! We are looking forward to continuing working with Dionyz.
Extend Python application using Twilio
August 2017
2nd time we have hired Dionyz and we will be hiring him again for another engagement. Fantastic work and great communication.
Attendance Text Message Application
August 2017
Dio is great. I'm a freelance designer in Denver, Colorado and was so happy to find him. Reliable, knowledgeable and just all around awesome.
Automated Data Scrape
August 2017
Great job, timely communication, completed work well before deadline. Highly recommended.
Web scraping to ID corporate marketing targets
July 2017
Very well done. Clean clear code. Solved my problem quickly. Recommended.
Scraping inside ajax/json using python
July 2017
Dionyz did fantastic work for us. Thoughtful approach, high quality results, under budget, and had good suggestions for other ways to improve the project. Highly recommended and hope we'll have the opportunity to work together again in the future!
Data scraping of credit unions data from single website
June 2017
Dionyz is a solid and rapid developer which delivered a succinct Python solution to an API connectivity issue that we had. Dionyz is pleasant to work with and has good communication skills. We hope to work with him again and can strongly recommend him to others.
Python Developer - Push API feed handler/subscriber - Web Sockets - WAMP Protocol
May 2017
Dio is a complete pleasure to work with. Gave details on what his approach was, did the work in the estimated time and was very flexible along the way. Great communication and I look forward to working with him again.
Python Script to Identify, Download and store youtube videos
May 2017
An excellent freelancer. Produces a high quality of work, ensures he has understood the brief and is very responsive. I am already using Dionyz on a new projects.
Python processing of data in multiple Excel spreadsheets
April 2017
Everything was going well, I decided to not complete the request. Dionyz was very thorough in asking for specs and starting the process.
Converting CSV Output to Fixed Format PDF
April 2017
Thanks for everything. look forward to working with you again soon. Have a great weekend.
Extract and save public data
April 2017
Perfect. This was a simple project, but I got a lot of proposals. Dionyz's solution to my problem most most effective and elegant. Thumbs up! Great job.
Script that saves a webpage as PDF
April 2017
Dionyz did a great job and delivered an elaborated and well documented software. Working in an agile style Dionyz reacted very fast on issues and solved everything to my complete satisfaction. Communication was very pleasant. I would work again with him.
I need a software to periodically download csv-files from Internet and store data into MySQL DB
April 2017
Everything went smoothly and the work was done quickly and with good quality.
Python script to gather Poloniex trade data into SQLite DB
March 2017
Great work. Dio not only did the programming itself very well (as far as I can tell as a non-programmer), he was also extremely helpful and communicative in terms of helping me understand and offer advice regarding the programming issues involved, which no doubt improved considerably on the project and at several stages ensured a better approach than I had originally envisioned.
Help building a Data Crawler to scrape data from job pages
March 2017
Really impressed with the quality of work produced. Did exactly what I asked him to do to the highest standard.
Expert Google Maps Scraper Needed
March 2017
Used Dionyz on several phases of a project. Easy to work with, reliable, the communication has been excellent and the work well done and on time. Can highly recommend him.
Changes to website
March 2017
Incredibly timely work with no bugs. Will definitely hire again.
Develop a Python or Powershell/.NET application to determine driving distance by address
March 2017
Creative solution, good code, and very quick turnaround.
Data scraping
March 2017
Can highly recommend Dionyz Lazar and will hopefully continue working with him on future projects.
Collect and put data into database with front end interface
February 2017
Dionyz was efficient and fast. very professional. Thanks mate !
I need a python developer for csv file analysis
February 2017
Working with Dio was an absolute pleasure and i highly recommend him.
Python Programmer
February 2017
Did what he said he would in the time quoted and at the price agreed on.. He was easy to get along with and to get changes made. Would highly recommend Dionyz to anyone looking for a prgrammer / developer.
Looking for a freelance python programmer to fix some code.
February 2017
Dionyz was very helpful and precise with the job.
Find travel time using Python
Projects
July 2019 -
Zenkraft - Multi-Carrier Shipping Integration
Zenkraft provides shipping, tracking and returns directly in Salesforce. 100% native apps used by over 50,000 users and over 20% of Fortune 500 for shipping booking, tracking, rating and much more on Salesforce™.
Initially, I was hired to migrate the codebase from Google App Engine to Heroku. After this initial migration was done, we've agreed on continuing the work, consisting mostly of integrating additional shipping carriers.
Shipping carriers are usually older companies with complex and legacy systems, so their APIs are less than ideal. Every carrier has their own API and while their function is virtually the same (create a shipment, return a label, schedule a pickup or track an existing shipment), the way they achieve these few methods differ vastly. The companies we work with typically don't have resources to integrate individual carriers and keep an eye on the integrations. So we offer one unified API, which provides a middle man from Salesforce to <insert carrier>. I'm the person who implements new carrier integrations & maintains all the old ones on the backend.
June 2019 - June 2019
Homer - Text Analysis Tool
Homer can help make your text more clear, simple and useful for the reader. Homer provides information on an overall text as well as on individual paragraphs and it gives insights into readability, length of paragraphs, length of sentences, average sentences per paragraph, average words in a sentence, etc. Homer also tries to identify certain kind of vague words as well as tracking the frequency of "and" words in the text.
For me, this was a chance to learn VueJS and combine it with my backend expertise to provide a whole solution.
July 2018 - May 2019
Newchip - API for iOS app
Newchip is a FinTech startup that helps people to invest into other startups and I was hired as a Django API developer there.
Newchip's main focus was developing an iOS app and I was responsible for the API built on top of Django (DRF) running on Heroku. One of the efforts I was a part of was creating a dashboard for paid users. We built a dashboard which allowed the user (owner of a startup) to see analytics about his funding deal. The dashboard also allowed the user to edit information about his deal and it was integrated with Chargebee subscription system.
I've learned a lot from this job in terms of agile software development, team work and leadership. It has given me a chance to grow professionally and to work with some very talented people.
July 2017 - October 2018
Sonder - Data Warehouse / ETL System
I was working with an US-based hospitality startup called Sonder as a Python Developer.
Their goal was to create a robust data pipeline able to collect from multitude of different data sources. In the end, it was 43 different sources, some of them from open data platforms provided by the US government, some were web scraped. From the technical side, it was mostly my own effort to both architect and implement a flexible, robust and easily extensible data pipeline.
July 2017 - October 2018
IntrospectData - Data Ingestion Toolset
IntrospectData is a Data Science startup and I worked with them as a Flask API developer.
I was given a set of Swagger documents detailing multiple APIs that were designed to work in a microservice manner. My responsibility was then to implement these specs in Flask with the use of MongoDB.
I had a chance to work with a very talented, experienced developer, who has shown me a lot from DevOps, automation and CI/CD systems. This job has been one of my favorite so far, simply because of the amount of fun I had learning and working on this.
Education
Masaryk University, Faculty of Informatics in Brno
September 2014 - January 2016Information Systems
Studied on Faculty of Informatics in Brno.
Masaryk University, Faculty of Informatics in Brno
September 2011 - September 2014Computer Systems and Data Processing
Studied on Faculty of Informatics in Brno. Degree was completed in 2014.