Dmitry is available for hire

Dmitry Lashkov

Verified Expert in Engineering

AI Agents Developer

Vilnius, Vilnius County, Lithuania

Toptal member since February 25, 2016

Expertise

Back-end Developers Full-stack System Security Ruby API AWS RDS Interim CTOs Prompt Engineering OpenAI Chatbot Development Remote Development

Bio

Dmitry is a software engineer with 15 years of experience. He has worked with large existing products, built complex ones from scratch, and hired and led remote teams of more than 10 people. Dmitry has the ability to focus, dive in, and gain a complete understanding of the problem he's solving. He loves automated tests, reviewed pull requests, and Agile methodologies because they allow developers to build quality products and iterate quickly. Ruby and Python are Dmitry's technologies of choice.

Portfolio

Clara AI

Large Language Models (LLMs), OpenAI, AI Agents, Python, Django, Pydantic...

Teamable

Ruby, Python, JavaScript, Vue, Vue 2, Alembic, SQLAlchemy, BigQuery, PostgreSQL...

Teamable

Ruby, Ruby on Rails API, Python, Flask, SQLAlchemy, Heroku...

Experience

SQL - 15 years
JavaScript - 14 years
Ruby on Rails (RoR) - 13 years
Test-driven Development (TDD) - 11 years
Python - 5 years
Chatbots - 2 years
Artificial Intelligence (AI) - 2 years
AI Agents - 2 years

Availability

Part-time

Preferred Environment

Git, Bash, Ubuntu, IntelliJ IDEA

The most amazing...

...thing I've built is a profile KNN vector similarity engine that momentarily ranks millions of candidates from most to least similar using one example candidate.

Work Experience

Founding Engineer

2023 - 2024

Clara AI

Designed and built the core of the scheduling assistant powered by LLM. Took into account race conditions, future expansion of business logic, and possible multiple communication channels. Ensured that the foundation is stable and well-tested.
Conducted extensive prompt engineering work for complex data extraction tasks and achieved high prompt accuracy.
Implemented efficient and instantaneous Google calendar synchronization using push notifications and covered complex edge cases like recurring events.

Technologies: Large Language Models (LLMs), OpenAI, AI Agents, Python, Django, Pydantic, ChatGPT, SQL, Git, Scrum, Test-driven Development (TDD), Linux, JavaScript, Ubuntu, Agile Software Development, Redis, Behavior-driven Development (BDD), PostgreSQL, Amazon Web Services (AWS), Bash, Chatbots, Artificial Intelligence (AI), JSON, User Stories, FastAPI, IntelliJ IDEA, Prompt Engineering, Unicorn, JSON API, YAML, HTML5, CSS3, HTML, Solution Architecture, Data Extraction, REST APIs, Architecture, Back-end, Back-end Architecture, CSS, Bots, OAuth, Software Architecture, Containers, GitHub, Redis Cache, Back-end Development, Startups, Object-relational Mapping (ORM)

CTO

2020 - 2023

Teamable

Built a remote engineering team of more than 10 people, authored coding challenges and conducted hundreds of interviews. Introduced cross-functional self-sufficient teams. Came up with tech debt management strategy.
Developed a candidate recommendation system based on Word2vec and the k-nearest neighbors algorithm. Came up with innovative embedding techniques that allowed me to accurately represent profile structure within a vector.
Introduced the first pages of the Vue app and led the effort to migrate the entire app from server-rendered Rails pages to Vue. Trained other engineers to use the Vue framework.
Built a chatbot that could find candidates for hiring. The chatbot would ask for a job description and then would show example candidates asking to approve or reject them. Generated a reach-out campaign text using LLM and started sourcing.
Built an experimental call bot that could join Zoom and Google Meet calls as a participant, transcribe everything that was said, understand spoken commands, and immediately make notes in Google documents.
Learned the business logic of a referrals startup and completely rewrote specifications to make it part of the main system. Initiated the rewrite work, then guided multiple teams to finish the rewrite based on specs.
Learned the business logic of a scheduling assistant startup and led other engineers to make sensitive changes and improvements.
Led the effort to Dockerize and transition all services from Heroku to AWS. All services were transitioned to ECS Fargate clusters quickly and without downtime, which resulted in increased stability, reduced costs, and better system monitoring.
Led the effort to create a stable and resumable ETL data pipeline from PostgreSQL to BigQuery to OpenSearch. Configured the PostgreSQL to BigQuery part of the pipeline using HevoData and worked with the data engineer to build the BigQuery to OpenSearch part.

Technologies: Ruby, Python, JavaScript, Vue, Vue 2, Alembic, SQLAlchemy, BigQuery, PostgreSQL, Amazon RDS, Amazon Elastic Container Service (ECS), Amazon Elastic Container Registry (ECR), Continuous Deployment, Docker, Docker Compose, Flask, Word2Vec, NumPy, K-nearest Neighbors (KNN), Elasticsearch, ChatGPT, SQL, Ruby on Rails (RoR), Git, Scrum, RSpec, Test-driven Development (TDD), Linux, Ubuntu, Agile Software Development, Redis, NPM, Behavior-driven Development (BDD), Amazon Web Services (AWS), Bash, Ruby Performance, Chatbots, Artificial Intelligence (AI), Factory Girl, Microservices, Express.js, Lean Startups, Model View Controller (MVC), JSON, Concurrent Programming, ACID, User Stories, IntelliJ IDEA, Cross-functional Team Leadership, Remote Team Leadership, Leadership, CTO, Prompt Engineering, Large Language Models (LLMs), React, Kanban, Unicorn, Nokogiri, Airbrake, JSONP, JSON API, JBuilder, YAML, HTML5, CSS3, Stripe, Node.js, SCSS, HTML, Solution Architecture, Data Extraction, Technical Leadership, Technical Hiring, REST APIs, Architecture, Full-stack Development, CI/CD Pipelines, Full-stack, APIs, Back-end, Back-end Architecture, Back-end Performance, CSS, Bots, Cloud Infrastructure, Selenium, OAuth, Software Architecture, Containers, GitHub, Redis Cache, Back-end Development, Team Leadership, Startups, Stripe API, Stripe Payments, API Platforms, Event-driven Architecture, Stream Processing, API Integration, Object-relational Mapping (ORM), Requirements Analysis, Google BigQuery, Data Pipelines, ETL, Looker, Applicant Tracking Software (ATS), Amazon OpenSearch, Amazon S3 (AWS S3)

Lead Engineer

2017 - 2020

Teamable

Extracted a high-load and sensitive Gmail synchronization service from a monolith app. Service integration was based on an event-driven architecture. The newly extracted service supported on-premise deployments to address customers' privacy concerns.
Spearheaded the effort to increase the stability of the overall system. Improved system design using best practices like the single responsibility principle, separation of concerns, encapsulation, and extensive test coverage. Introduced CI/CD pipelines.
Build the first version of customer-facing reports and the first version of automation for the back-office human-in-the-loop tool.
Stabilized background job processing systems using Redis/SQL locks and introduced the concept of unique jobs, differentiated queues, and workers.
Increased the stability and speed of a browser extension several times by breaking up several expensive back-end calls into smaller ones processed asynchronously. Additionally, the extension used innovative and reliable page parsing techniques.
Led the team working on the applicant tracking system (ATS) data ingestion pipeline. The isolated ATS data ingestion service was processing data from different ATSs and sending standardized ATS events to the main system.

Technologies: Ruby, Ruby on Rails API, Python, Flask, SQLAlchemy, Heroku, Continuous Deployment, SQL, Ruby on Rails (RoR), Git, Scrum, RSpec, Test-driven Development (TDD), Linux, JavaScript, Ubuntu, Agile Software Development, Redis, NPM, Behavior-driven Development (BDD), PostgreSQL, Amazon Web Services (AWS), Bash, Ruby Performance, Factory Girl, Microservices, Express.js, Lean Startups, Model View Controller (MVC), JSON, Bower, Concurrent Programming, ACID, User Stories, IntelliJ IDEA, Amazon Elastic Container Registry (ECR), Vue 2, Remote Team Leadership, Leadership, Amazon RDS, Amazon Elastic Container Service (ECS), Vue, React, Kanban, Unicorn, Nokogiri, Airbrake, Capybara, JSONP, JSON API, JBuilder, Grunt, YAML, HTML5, CSS3, Node.js, SCSS, HTML, Solution Architecture, Data Extraction, Technical Leadership, REST APIs, Architecture, Full-stack Development, CI/CD Pipelines, Full-stack, APIs, Back-end, Back-end Architecture, Back-end Performance, CSS, Bots, Cloud Infrastructure, Selenium, OAuth, Software Architecture, GitHub, Redis Cache, Back-end Development, Team Leadership, Startups, API Platforms, Event-driven Architecture, API Integration, Object-relational Mapping (ORM), Requirements Analysis, ETL, Data Pipelines, Looker, Applicant Tracking Software (ATS), Amazon S3 (AWS S3)

Lead Full-stack Developer

2017 - 2017

Ourea

Led a team of developers to convert a single-tenant fintech app into a multi-tenant one.
Implemented reliable imports of customer and financial data.
Helped pick the next best feature based on the ROI.
Managed tech debt, helping to make refactoring decisions based on tradeoffs between long-term stability and immediate development time investment.
Worked on improving the reliability of microservices integration.
Introduced peer-reviewed pull requests and continuous deployment with CircleCI.

Technologies: JavaScript, SCSS, HTML, PostgreSQL, Sidekiq, Ember.js, RSpec, Ruby on Rails (RoR), Ruby, SQL, Git, Scrum, Test-driven Development (TDD), Linux, Ubuntu, Bash, JSON, Bower, Handlebars, ACID, IntelliJ IDEA, Heroku, Leadership, JSON API, Ember Data, HTML5, CSS3, Node.js, Technical Leadership, REST APIs, Full-stack, APIs, Back-end, CSS, GitHub, Back-end Development, Team Leadership, Object-relational Mapping (ORM)

Full-stack Developer

2016 - 2017

Surge AI

Wrote a flexible client crediting solution allowing clients to hire workers for one-off online jobs. Clients could use both prepaid mode and weekly/monthly charges based on the amount of services used. Credit limit and other limits were put in place.
Found and fixed multiple race conditions and other bugs in the previously written PayPal integration code for incoming client and outgoing worker payments. As a result, the company stopped losing money because of incorrectly processed payments.
Introduced the DRY principle, lean models, and a controller approach by extracting business logic into specialized service classes. All new code, including service classes, received full coverage with specs.
Found and fixed bugs in the subsystem accounting for the amount of work done by workers.
Made the whole test suite pass by fixing all previously broken tests, introduced Better Specs guidelines, and continuous deployment using CircleCI.
Optimized slow and complex SQL queries by replacing nested queries with outer joins.
Improved the quality of the code submitted by colleagues by carefully reviewing pull requests.

Technologies: Airbrake, Puma, HTML, SCSS, Haml, Stripe, Capybara, Sidekiq, RSpec, PostgreSQL, Ruby on Rails (RoR), Ruby, SQL, Git, Linux, JavaScript, Ubuntu, Bash, Model View Controller (MVC), JSON, ACID, IntelliJ IDEA, Heroku, JSON API, HTML5, CSS3, Full-stack Development, Full-stack, APIs, Back-end, CSS, GitHub, Back-end Development, Stripe API, Stripe Payments, Object-relational Mapping (ORM)

Lead Front-end Developer

2016 - 2016

Anatas

Integrated the app with a new infrastructure of Node.js Express microservices used to control CloudFoundry.
Led a team of developers reviving and migrating an Ember 1 enterprise cloud management app without Ember Data to Ember 2 with Ember Data. The goal of winning corporate tender was successfully achieved.
Improved UI/UX and in-app workflows. Introduced Ember components with a "data down actions up" approach.
Introduced SCSS with multiple partials, mixins, and variables instead of one CSS file.
Cleaned up the codebase and enforced strict coding standards on pull requests using ESLint. Added back-end mocking with Mirage.

Technologies: SCSS, Cloud Foundry, MongoDB, Mirage, Ember CLI, Node.js, Ember.js, SQL, Git, Scrum, Linux, JavaScript, Ubuntu, Agile Software Development, Bash, Express.js, JSON, IntelliJ IDEA, Remote Team Leadership, JSON API, HTML5, CSS3, HTML, REST APIs, Full-stack Development, APIs, Back-end, CSS, GitHub, Back-end Development, Object-relational Mapping (ORM), NoSQL

Full-stack Developer | CTO | Co-founder

2014 - 2016

Playgong

Implemented a fully-fledged API for Android, iOS, and Ember apps from scratch.
Set up process monitoring with Monit to quickly recover from possible downtimes.
Built a responsive Ember CLI app that consumes the API and reports JavaScript errors to Errbit.
Extended the Rails architecture with class groups like services (for business logic), policies (for authorization), and queries (for fetching records) to avoid bloated controllers and models.
Implemented an effective API versioning scheme with only the two latest API versions to maintain.
Set up continuous deployment (CD) process via Jenkins, automated tests, and hot unicorn deploys via Capistrano.
Implemented leaderboard versioning, allowing users to change any game result and recalculate the leaderboard state.
Achieved 100% test coverage of the codebase with unit, controller, and integration tests.
Set up a separate Ember deployment process with asset uploads to Amazon S3 and API behind an NGINX reverse proxy.

Technologies: Amazon Web Services (AWS), SCSS, HTML, Sidekiq, RSpec, MySQL, Ember CLI, Ember.js, Ruby on Rails (RoR), Ruby, SQL, Git, Test-driven Development (TDD), Linux, JavaScript, Ubuntu, Agile Software Development, Redis, Behavior-driven Development (BDD), Bash, Factory Girl, Model View Controller (MVC), JSON, NGINX, ACID, IntelliJ IDEA, Continuous Deployment, Heroku, JSON API, Ember Data, HTML5, CSS3, Solution Architecture, REST APIs, Architecture, Full-stack Development, Full-stack, APIs, Back-end, Back-end Architecture, CSS, OAuth, Software Architecture, GitHub, Back-end Development, Startups, Object-relational Mapping (ORM)

Ruby Developer

2013 - 2014

Vinted

Worked on implementing an escrow subsystem of the marketplace by integrating a white labeled payment system via REST API.
Integrated package delivery monitoring for the escrow subsystem.
Led a team as a scrum master to implement vouchers for the marketplace.
Developed company account balance calculation that separated voucher money from escrow money and showed turnover.
Implemented funnel tracking in the internal analytics tool.
Implemented app-wide feature switches and integrated them with existing A/B test functionality.
Refactored old parts of the system via a two-step process of new tests first and refactoring itself second.
Eliminated race conditions in an internal marketing campaign tool.

Technologies: Delayed Job, RSpec, MySQL, Ruby on Rails (RoR), Ruby, SQL, Git, Scrum, Test-driven Development (TDD), Linux, JavaScript, Ubuntu, Agile Software Development, Redis, Bash, Factory Girl, Model View Controller (MVC), JSON, Underscore.js, ACID, User Stories, IntelliJ IDEA, Continuous Deployment, Kanban, Memcached, HTML5, CSS3, HTML, Full-stack Development, Full-stack, APIs, Back-end, CSS, GitHub, Back-end Development, Object-relational Mapping (ORM)

Full-stack Developer

2012 - 2013

Same System

Implemented a retail shop network budget analysis tool from back-end to front-end.
Maintained and updated the salary calculations subsystem for various jurisdictions.
Rewrote the vacation planner and other old and neglected parts of the system.
Eliminated numerous haunting false positives from headless browser Cucumber integration tests using a deterministic approach.
Developed a library for time segment calculus and a library for table generation in CSV, HTML, and JSON formats.

Technologies: JavaScript, Delayed Job, MySQL, Ruby on Rails (RoR), Ruby, SQL, Git, Scrum, RSpec, Linux, Ubuntu, Agile Software Development, Behavior-driven Development (BDD), Bash, Factory Girl, Model View Controller (MVC), JSON, ACID, User Stories, IntelliJ IDEA, Continuous Deployment, Heroku, Kanban, HTML5, CSS3, HTML, Back-end, CSS, Back-end Development, Object-relational Mapping (ORM)

Full-stack Developer, Co-founder

2011 - 2012

Tenderella

Designed a PostgreSQL database for various tender types and accompanying official notices. Created a web scraper for public tenders using Ruby. Integrated Resque with Rufus Scheduler for periodical runs of the web scraper.
Used Ruby on Rails single table inheritance and polymorphic associations to solve the problem of many types of tenders and notices.
Integrated Solr for fast and relevant tender search.

Technologies: Nokogiri, Apache Solr, PostgreSQL, Ruby on Rails (RoR), Ruby, SQL, Linux, JavaScript, Ubuntu, Bash, Model View Controller (MVC), JSON, NGINX, ACID, IntelliJ IDEA, HTML5, CSS3, HTML, Data Extraction, Back-end, CSS, Back-end Development, Startups, Object-relational Mapping (ORM)

Experience

Konstructor | Ruby Gem

https://github.com/snovity/konstructor

This gem allows the creation of multiple constructors in Ruby in an idiomatic way. This helps in cases when an object needs to be constructed in several different ways. It is small, fast, thread-safe, and doesn't depend on other gems.

Quantum Modeling of Simple Molecules

A C# application that simulates hydrogen, oxygen, and carbon atom collisions, covalent bonds, associations, and dissociations for water and methane molecules. The app accounts for quantum effects using an algorithmic approach that is based on constructive physics. The core idea is to represent each atom by several imaginary interconnected atoms to simulate a quantum wave packet.

Casual Multiplayer Games

I developed the front-end part of multiplayer dice and dominoes games written in ActionScript for the Flash platform. These games were fat clients, and I simulated back-end logic for better game responsiveness. After getting a response, the front end confirmed its calculations with the back-end.

Intranet Drug Accounting System

A web app for the internal network of a big medical complex was integrated with an accounting Windows app used by the facility. Departments started using the new web app to manage drug distribution and consumption and no longer needed a license for a desktop client of the accounting app. It saved the medical facility a fortune.

Education

2004 - 2009

Specialist's Degree in Software Engineering and Applied Mathemtatics

Moscow State University - Moscow, Russia

Skills

Libraries/APIs

JSON API, Node.js, Nokogiri, Sidekiq, JSONP, Ruby on Rails API, Pydantic, SQLAlchemy, REST APIs, Delayed Job, Stripe, Handlebars, Ember Data, Underscore.js, Vue, Vue 2, NumPy, Stripe API, React

Tools

Airbrake, JBuilder, RSpec, NPM, Git, Amazon Elastic Container Service (ECS), Docker Compose, ChatGPT, GitHub, Looker, Grunt, NGINX, Bower, Amazon Elastic Container Registry (ECR), Amazon OpenSearch, Apache Solr, BigQuery, IntelliJ IDEA

Languages

HTML, Python, HTML5, Ruby, YAML, SQL, SCSS, CSS, CSS3, JavaScript, C, Unicorn, Bash, C++, C#, Haml, Microsoft Assembly x86 (MASM), ActionScript 3

Frameworks

Capybara, Express.js, Ruby on Rails (RoR), Ember.js, Flask, Factory Girl, Selenium, Django, Alembic

Paradigms

Microservices, Concurrent Programming, Behavior-driven Development (BDD), Object-oriented Programming (OOP), Scrum, Test-driven Development (TDD), Model View Controller (MVC), ACID, Continuous Deployment, Back-end Architecture, Event-driven Architecture, Object-relational Mapping (ORM), Requirements Analysis, Agile Software Development, Kanban, ETL

Platforms

Heroku, Docker, Linux, Amazon Web Services (AWS), Ubuntu, FreeBSD

Storage

JSON, PostgreSQL, Redis, Memcached, MySQL, Elasticsearch, Redis Cache, Amazon S3 (AWS S3), MongoDB, Data Pipelines, NoSQL

Other

Ruby Gems, Lean Startups, User Stories, Ruby Performance, Prompt Engineering, Amazon RDS, CTO, Remote Team Leadership, Word2Vec, K-nearest Neighbors (KNN), OpenAI, AI Agents, Chatbots, Solution Architecture, Data Extraction, Technical Leadership, Technical Hiring, Architecture, Full-stack Development, CI/CD Pipelines, Full-stack, APIs, Back-end, Back-end Performance, Bots, OAuth, Software Architecture, Back-end Development, Team Leadership, Startups, API Platforms, API Integration, Applicant Tracking Software (ATS), Puma, Ember CLI, Large Language Models (LLMs), Leadership, Cross-functional Team Leadership, Cloud Infrastructure, Containers, Stripe Payments, Stream Processing, Mirage, Cloud Foundry, Artificial Intelligence (AI), Quantum Computing, Image Recognition, System Programming, Physics, Calculus, Probability Theory, FastAPI, Google BigQuery

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