About me

Hi! I'm Yakov K.

I am a full-stack dev with skills and interests in various things, all engineering. My whole career I've been working with different tools, and I have acquired experience with Backend, Frontend, Mobile, DevOps, and all things in-between while doing different stuff. I value soft skills highly and have experience in forming teams, conducting interviews, and leading developer groups. I am passionate about mentoring and explaining difficult stuff in simple words.

My current stack that I use daily consists of Dart, Flutter, Nix, TypeScript, and SQL, while I'm also working closely with Swift, Kotlin, Bash and Haskell. I'm accustomed with Python, Java, Elixir, F#, and C/C++. I work with macOS/Linux as my daily driver, and worked in various fields, from AI and web3 to fashion-tech and fin-tech, mostly with USA/Canada-based companies and start-ups.

As of now, I'm mostly doing consulting, training, and contract work, and building my projects, most of which are open-source. This page is open-source as well.

You can shoot me an email if you have something to discuss – I'm always open to collaborate on new ideas and interesting projects to work on and passionate about helping businesses and start-ups leverage their tech to the max :)


A list of my projects. Here you can find mobile apps, websites, and (a little too much of) open-source tools, libraries, and packages. You can find my relevant working experience on LinkedIn, as here are listed only projects that I have full ownership of, even if the project was made as part of a contract agreement.

Mobile apps


open-source Haskell TypeScript Dart Flutter SQL

Advanced task manager that allows for defining sequential task flows using graphs of dependencies. Automatically determines priority, order, and available tasks for complex flows.

Pastsworthy Storage

open-source* Dart Flutter App Store

An application for storing, generating, and manipulating sensitive data with military-grade encryption, local-first


Swift SwiftUI App Store

A previous iteration of Passworthy Storage, fitting for generating secure passwords and other secrets.

Measuring units

Swift SwiftUI Combine Limitied NDA

An application for converting and transforming streams of data consisting of different measuring units with requirements for real-time conversion on the spot. Made for an external client.


Flutter Dart SQL Nix AppStore

A mood diary that forces the user to describe emotions and their anchors, forcing them to establish patterns between actions and emotions. Fully encrypted and prioritizes a local-first approach.


open-source* Flutter Dart

Language training app that teaches non-latin alphabet letters by example. Intended for beginners learning languages, utilizing pronunciation-visual relation for memorizing letters.

Medical E-comerce

Flutter Dart AppStore Limited NDA

An e-commerce application of medical products and services for people with disabilities. Focused on autoimmune-related topics.


This blog

web open-source Dart Nix Reify Cloudflare

This blog. Made in pure Dart using my Static Site Generator, Reify. Written in reactive templateless eDSL and classless CSS.


webFlutter Web Dart Cloudflare open-source

A stupid site that I made out of spite because an online form was being picky.

Server SaaS


Crypto Haskell Nix Limited NDA



Social Node TypeScript Limited NDA

An invite-only application, made as a proof of concept for a proprietary algorithm. Allows for establishing multi-way social connections through anonymous invites.


Consulting / Contract

As of now, I'm mostly doing consulting/contractor work, which is a broad description for numerous reasons. I have worked with different startups, companies, and agencies on different tasks, and things tend to not be the same across the context.

Contact me by mail if you have something to discuss, I truly love to help resolve pain-points, big and small :)

In the last years, I have worked with b2b, b2c, crypto-, health-, finance-, ai- and other fields. Either helping with existing solutions, helping with forming and structuring teams, establishing a productive flow and tech stack, mentoring and training engineers, conducting technical interviews, implementing core features and architectural examples, and things in between.

I don't have a fixed hourly/project rate, as those details are highly project-specific, and range depending on the scope and the kind of work.


Over the years I contributed to a list of open-source and free projects, libraries, and applications alike.

I value my contributions to the OpenAPS (artificial pancreas system) project, but most of my contributions are directed towards ecosystems of the tools that I use. Dart, Haskell, and Nix being my points of focus. Open source community is one of the best places to collaborate on things that benefit all developers, and it is something that I firmly believe in.


Packages & tools

Core Flake

Open source Nix Flakes Template

Concise and expressive base flake. Replaces existing solutions by providing a smarter API that requires as little info as possible and derives large chunks by abstracting dependencies and outputs.

Home Flake


My working setup, fully in Nix. Uses nix-darwin for system-wide integrations on macOS and Home Manager for everything else. Depends on Core Flake.

Nix Act

Open source Nix GitHub Actions

A composed GitHub Action that installs Nix, enables caching, and does other set-up actions for immediate setup. Best used with flakes.


Open source Dart Nix GitHub Actions Template

Templateless, Declarative, Component-based Static Site Generator that this site is powered by. Allows for hot reload of both Components and sources.


Open source Dart

Functional essential. Does not implement any language-specific, foreign concepts from other languages, but brings atomic building blocs for writing idiomatic Dart code, in functional style.


Open source Dart

Data-driven logging library that treats log entries as typed objects, allowing for processing by multiple implementations of processors, structured logging, and handling the whole process as functions over data. Used in almost every application listed above.

Purple Starter

Open source Dart Flutter Template

Base Flutter template that makes starting a new application a breeze, allowing for fast iteration while maintaining industry-level quality. Utilizes a range of packages and creates an architectural foundation universal for most Flutter apps.

Purple Lints

Open source Dart

My hand-picked list of dart lints. Tailored by balance on being as strict as possible, while also being reasonable and resulting in concise, maintainable code


Open source archive Dart Flutter

Graph-based Dependency Injection framework. One of the previous works that resulted in Sym.

Typed Preferences

Open source Dart Flutter

Typed, DAO-based SharedPreferences driver. Adds a layer of type safety through abstracted field definitions through flexible schemas.

Snippy Templates

Open source Dart VS Code Template

Declarative snippets generator for VSCode for decoupled and human-readable templates. Each template is defined in its file, after which they are transformed and combined into a resulting artifact.


Open source Dart Flutter

Modern implementation of the original Business Logic Component that uses asynchronous generators to describe relationships between events and states. Being one of the previous foundational works for Sym, it is still very much relevant.

Makefile & Markdown for Dart

Open source Dart

A set of composable parsers and renderers that fit nicely together. Used for automatic documentation generation for Makefiles in Purple Starter.


Open source archive Dart

Sum types / Unions expressed in Dart for asynchronous data, error handling, and more. Archived and replaced by Luna for more flexibility and control.


Open source Dart

A simple and fast implementation of REPL for Dart. Can be used as a lightweight and local analogue for online compiles as a playground or an environment for debugging.

Scoped Logger

Coming soon Haskell

Lightweight, monadic, fast, and abstract implementation of a structured logger with scopable message processors. Heavily polymorphic and customizable, which allows for un-opinionated usage.


Coming soon Dart

Serialization package that uses pseudo polymorphism instead of code generation for defining serialization rules. Completely eliminates the need for a build step.


Coming soon Dart

Instant generator for Algebraic Data Types. Reduces build step times 100 fold, while leveraging current language features for producing compile-time safe Sum and Product types.


Coming soon Flutter Dart DI State management Microframework

Reactive microframework for declarative encoding of Business Logic. Ties together Dependencies, State, and Site Effects in graphs that describe the behavior of the application, allowing for rapid development. Used by a lot of applications listed here.