Sebastian is available for hire

Sebastian Cherny

Verified Expert in Engineering

Software Developer

Madrid, Spain

Toptal member since September 2, 2022

Expertise

Algorithms Google Drive Development Front End Back-end Developers Full-stack Web Development Data Visualization C++Python Linux Git SQL MySQL JSON Microsoft Teams Development

Bio

Sebastian has been a developer since he finished high school. He fell in love with programming once he realized how powerful it is in solving problems. Sebastian is about to finish a career in math, and his goal is to be able to combine math and programming in projects with social impact.

Portfolio

Toptal

Django, PostgreSQL, Python, Forms, Wizards, Authentication, PDF, CSV, CSS

Freelance Clients

Python, Django, Django REST Framework, Django ORM, Azure, OpenAI, ChatGPT API...

Codegen, Inc.

Python, PostgreSQL, FastAPI, SQLAlchemy, Artificial Intelligence (AI), OpenAI...

Experience

Spreadsheets - 10 years
Python - 9 years
Databases - 9 years
HTML - 8 years
APIs - 8 years
REST APIs - 8 years
CSS - 8 years
JavaScript - 5 years

Preferred Environment

Django, Python, React, PostgreSQL, Visual Studio, MacOS, Linux, JavaScript, Docker

The most amazing...

...project I've developed and launched in just a few months was a code refactor for a huge company with 2,000 daily users.

Work Experience

Django Developer

2024 - 2024

Toptal

Developed an app for users to create products in a database from scratch within a wizard, where each step was for a different table linked to the product. The user can see the list of created products and download a CSV with its data (with the corresponding columns) to use as a template for creating multiple similar products.
Created a Selenium test to simulate the user flow, logging in, creating an asset, and uploading a PDF. This was important to ensure that the system was working as expected and to catch possible errors in future code changes.
Created a README that specifies how to run the tests and make a code change for specific situations, given that the client wasn't an expert in Python.
Monitored deployment through VPN to a secure server.

Technologies: Django, PostgreSQL, Python, Forms, Wizards, Authentication, PDF, CSV, CSS

Python Back-end Developer

2024 - 2024

Freelance Clients

Developed a system that automatically sent a request to OpenAI and stored the clean response in the database for future use and display.
Improved the Django Admin so that seeing the data stored in the database was easier and clearer. Developed a system that automatically sent a request to OpenAI and stored the clean response in the database for future use and display.
Added unittest and Selenium tests within the code, which are important for catching bugs and seeing that the platform works locally.

Technologies: Python, Django, Django REST Framework, Django ORM, Azure, OpenAI, ChatGPT API, PostgreSQL, Testing, Selenium, Stripe

Back-end Developer (via Toptal)

2024 - 2024

Codegen, Inc.

Created the testing structure for the whole repo, including mock objects and expected inputs and outputs.
Developed many codemods, which are scripts that would modify a repository according to the client's specifications.
Created the GitHub Action for the tests to run automatically, and I also made frequent test reports to analyze the metrics about how much testing the developers did.

Technologies: Python, PostgreSQL, FastAPI, SQLAlchemy, Artificial Intelligence (AI), OpenAI, Pytest, GitHub API

Full-stack Python Developer (via Toptal)

2023 - 2023

FLock.io LTD

Created a web app for authenticated users to upload PDF files and run an AI model in the back end to get a report on the PDF content.
Automated the process of importing a repo as a local library so as to allow different versions of the AI model.
Created many web scrapers to download public PDF files from different pages, read the PDF data, and organize it in a predefined JSON structure.
Downloaded some public GitHub repos using their API from the GitHub/GitLab/Bitbucket links mentioned in the scraped PDFs. Then, the script would check out a specific commit in the repo and use the files to train the AI model.

Technologies: Python, Full-stack, Django, APIs, Amazon Web Services (AWS), React, Docker, Smart Contracts, Selenium, Web Scraping, PostgreSQL

Full-stack Engineer

2023 - 2023

Stealth Health Company

Created a Django admin view for users to upload PDFs and send them by fax and Selenium tests to simulate a user going through every situation of the flow.
Developed a scraper with Selenium to obtain information from a link and scrape through its pages; also set up the corresponding unit testing.
Added onboarding documentation so that new developers can install and have everything running smoothly locally.

Technologies: Python, JavaScript, SQL, Django, Object-relational Mapping (ORM), Amazon Web Services (AWS), Docker

Full-stack Python and React Developer

2022 - 2023

Christenson and Recendes Company

Developed a web app that allows users to register and upload datasets and analyze bar graphs, pie charts, and heatmaps to better understand the data and report to the admins when something is off.
Set up automatic deploys to render after each commit so my clients have the latest version online.
Created a ticketing system inside the app so admins can approve and communicate with new users.

Technologies: Web Dashboards, Python, React, Django, APIs, Amazon Web Services (AWS), PostgreSQL, Full-stack, CSS, Bootstrap, HTML5, JavaScript, Chart.js, Fetch, Front-end, Heatmaps, Web Scraping, Visual Studio, Data Visualization, JSON Web Tokens (JWT)

Freelance Software Engineer

2022 - 2022

The Numericus Group

Developed a mathematical model to predict future temperature values based on past information, improving previous versions by 10% on average.
Created tests that allowed new code to be tested before deployment.
Facilitated a report table to compare previous and actual predictions.

Technologies: Python, OOP Designs, Jupyter Notebook, Linux, Git, Back-end, JSON, Applied Mathematics, Testing, PostgreSQL, Object-oriented Programming (OOP), GitHub, Visual Studio, Data Visualization

Software Engineer

2018 - 2022

MercadoLibre

Created a system that allowed 200 data entry professionals to generate sheets in Google Drive and share them.
Maintained the code to create changes requested by users and, consequently, facilitate their work.
Oversaw a deployment process after each change to verify that everything worked properly.

Technologies: Python, JavaScript, Google Drive, HTML, CSS, MySQL, Linux, Git, APIs, Front-end, Back-end, Amazon Web Services (AWS), REST APIs, JSON, Django ORM, Django REST Framework, Google Drive API, Testing, SQL, Databases, Front-end Development, Unit Testing, Functional Testing, Full-stack, Full-stack Development, Agile Software Development, Amazon EC2, Amazon S3 (AWS S3), Web Development, HTML5, Object-oriented Programming (OOP), Django, Microservices, GitHub, Bootstrap, API Integration, Visual Studio, Agile, Automation

Software Engineer Intern

2021 - 2021

Software Engineer Intern

2020 - 2020

Software Engineer

2016 - 2018

Brightsector

Developed (on my own) a set of alarms that would run on Icinga continuously and send emails if something started to fail.
Implemented alarms to test the deployment of new code, running everything on a pre-production environment.
Created alarms based on my own ideas, catching bugs in the code before deploying it to production.

Technologies: Python, Icinga, Amazon Web Services (AWS), Linux, Google Drive, Testing, Unit Testing, SQLAlchemy, Client-server Model, Agile Software Development, Amazon EC2, Amazon S3 (AWS S3), Object-oriented Programming (OOP), Microservices, GitHub, Bootstrap, Agile, Automation

Software Engineer

2014 - 2015

Brightsector

Developed a web scraper, using Python and XPath, that looked for products that different top companies were selling.
Took feedback from data entries and made adjustments to improve the process.
Maintained a database for the products created to produce an entire catalog, adding more than 1,000 products per week.

Technologies: Web Scraping, Python, Google Drive API, Back-end, Amazon Web Services (AWS), Testing, Databases, MySQL, XPath, XML, SQL, Client-server Model, Object-oriented Programming (OOP), GitHub, Selenium, Automation

Experience

Web App for Math Olympiad Problem Solving

A web app to create and solve mathematical problems for high school students training for the Math Olympiads. The app set weekly tasks, and users would get points if they solved them correctly during the first hour. In addition to working mainly on the front end using JavaScript, I set up some communication with the back end using Go.

Tournament Creator and Tracker

A web app used by a table football tournament organizer to create teams and track points and matches. It also records data. Before the app, the organizer did everything manually, so counting the points to have a trustworthy table took several minutes. I created the entire app and deployed it online.

Food App for Restaurants

A program used for communication between restaurant staff: Servers create food orders, chefs see them, and servers and other users track the status of orders. I collaborated with a team and was in charge of user communication, ensuring that the chat and status tracking system were user-friendly.

Competitive Programming

I've participated in many virtual international contests (Codeforces, TopCoder, HackerRank, and AtCoder). This required fast solving of original competitive problems, participation in ICPC Regional five times (in teams), obtaining 6th place in the region South-America South in 2020 and 2018; I was the main coder of the team.

Education

2014 - 2023

Master's Degree Candidate in Mathematics and Computer Science

University of Buenos Aires - Buenos Aires, Argentina

Skills

Libraries/APIs

React, REST APIs, Django ORM, Google Drive API, SQLAlchemy, Pandas, Chart.js, GitHub API, Stripe

Tools

Git, GitHub, Spreadsheets, Plotly, Visual Studio, Microsoft Teams, Pytest, cURL Command Line Tool

Languages

Python, JavaScript, SQL, HTML, CSS, C++, TypeScript, HTML5, PHP, Hack, R, Go, GraphQL, Visual Basic .NET (VB.NET), Java, XPath, XML, Bash

Frameworks

Django, Django REST Framework, Bootstrap, Selenium, Jest, JSON Web Tokens (JWT)

Paradigms

Testing, Unit Testing, Responsive Web Design (RWD), Agile Software Development, Object-oriented Programming (OOP), Agile, Automation, API Architecture, Functional Testing, Microservices, Object-relational Mapping (ORM)

Platforms

Jupyter Notebook, Linux, Amazon Web Services (AWS), Amazon EC2, MacOS, Icinga, Windows, Docker, Azure

Storage

MySQL, JSON, Databases, Amazon S3 (AWS S3), Google Cloud, SQLite, PostgreSQL, Microsoft SQL Server

Other

Competitive Programming, Google Drive, APIs, Front-end, Back-end, Algorithms, Front-end Development, Full-stack, Full-stack Development, Web Development, API Integration, Web Dashboards, Fetch, Data Visualization, OOP Designs, Applied Mathematics, Web Scraping, API Design, Client-server Model, Responsive Design, eCommerce, Heatmaps, FastAPI, Artificial Intelligence (AI), OpenAI, Smart Contracts, ActiveCampaign, ChatGPT API, Forms, Wizards, Authentication, PDF, CSV

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