Welcome to my page

My name is Jose Vargas

I am a freelancer from Costa Rica, I offer development and consulting services to grow your software product. I specialize in web app development and eCommerce.

You should work with me because:

  • I will make sure your product feels valuable to your users.
  • The product we build will last for years, I will make sure you don't forget any important detail.
  • I have professional experience working on every layer of large web applications: I can build your UI, improve your UX, build the server-side infrastructure, add third-party integrations, design a database, improve performance, configure a CI/CD pipeline, and add the relevant documentation so that other engineers can get up to speed with ease.

I specialize in the following technologies:

  • TypeScript, Elixir, Rust, Clojure, NixOS, Docker, PosgreSQL, AWS.

Blog posts

  • Verify HMAC signatures in Deno[link]

    Here I explain how to verify cryptographic HMAC signatures with TypeScript in Deno, and by extension in the browser as well. In this specific example I demonstrate how to verify these signatures for Paddle Webhooks.

  • NixOS Minecraft Server in AWS[link]

    This is a tutorial on how to deploy a NixOS server to AWS EC2 from a MacOS computer. In the exercise the server instance is utilized to host a videogame (Minecraft) that other players can join. Uses Docker for building and deploying the NixOS from the local computer to AWS EC2. Includes a custom SystemD service that I wrote in Rust to monitor the server and turn it off automatically when there are no players connected to the game.

  • Making my Static Blog Generator[link]

    Covers how I created my own Static Site Generator using the Rust programming language. This is the project that I currently use to publish my blog. The article is aimed at people who are in the process of learning Rust and desire to also create their own blog.





Hobby Projects

  • My blog[link]

    Built with Rust. How I did it & GitHub.

  • Test scores graphs[link]

    Small website to showcase VegaLite graphs inside a Phoenix app. Uses a CSV file as a data source, displays the percentile of median scores for LSAT tests across different universities.

  • Movie search front-end[link]

    A small project to showcase ReactJS with Typescript, TailwindCSS and Jest. GitHub.

  • Yin Yang Fractal Animation[link]

    A geometric animation created with C++ and the OpenFrameworks library. Try to imagine what it looks like before you open the link! GitHub.

  • This portfolio[link]

    Built with NextJS and TailwindCSS. GitHub.

Professional Services

I can help you with the software development of your project. Whether you are starting your project from zero or you need help extending an existing project I can help you succeed, from product ideation to software implementation. Reach out in one of the platforms below.


I am currently available to work with new clients. The pricing depends on the characteristics of the job, you can calculate the hourly charge by selecting the qualities of the job.

Hourly cost
80 USD
Open Source Discount
-20 USD
Fixed Schedule
10 USD
Daily meetings
10 USD
Managerial role
20 USD
Total hourly cost:
80 USD

I can offer dynamic pricing, for example, if you want some fixed hours of work when we may collaborate, but other hours are flexible. Get in touch with me and we will iron out the details.