👋 Hi! I'm a freelance senior software engineer specializing in data visualization. I worked for prestigious research centers and top-tier companies. I've also developed extensive educational content that you might benefit from. ❤️

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Yan Holtz profile picture

Hi, I'm Yan.

I specialize in helping companies and researchers analyze and visualize their datasets. I excel in data visualization. If you're looking for guidance on presenting your results or building complex interactive charts, I'm the expert you're seeking.

With a solid 12-year track record in data science, I've collaborated with prestigious research institutes like the University of Queensland and leading private companies such as Datadog.

I am now working as a consultant and on my educational websites like data-to-viz.com, Productive R Workflow and the graph galleries.

Publications Talks Twitter Github
2016 Data Analyst French Institute of Research 2017 Data Analyst Terres Inovia 2019 Data visualization Qld Brain Institute 2024 Software Engineer Datadog Data - Science - Viz Consultant


Let me help make better use of your data. I offer consulting, training, and speaking engagements.


Hire me to talk about programming or data visualization. I ❤️ it!



Need a custom interactive graph? Some R or React work? Creating beautiful reports with Quarto?


Teaching & Training

Short talks or multi-day courses on dataviz, R, ggplot2, data analytics and more.



"Dataviz Universe" is my newsletter where I share my latest dataviz updates. If you like charts, you will love my tips and tricks!


I've developed several websites dedicated to data visualization. These resources are visited about 30.000 times a day.

from Data To Viz

A classification of charts based on their input format, and a lot of tips and tricks.


Dataviz inspiration

A collection of my favorite dataviz project in a pinterest style.


R Graph Gallery

Hundreds of R charts, always with reproducible code and explanations.


Python Gallery

A gallery of charts made with python, with a focus on Matplotlib and Seaborn.


D3 Graph Gallery

D3 is the ultimate tool for data visualization on the web. Tedious but limitless.


React Graph Gallery

Learn how to integrate d3.js graphs with React, the most widely used Javascript library.

Yan Holtz profile picture

Productive R Workflow is my latest project.

It's an online course designed for R users, offering a comprehensive collection of best practices that are essential for enhancing your workflow.

Whether you or your team use R, dedicating a few hours to this course will be immensely beneficial and enjoyable.

Trust me and take a look!

Be better at R, now

Dataviz Decision Tree

Unsure which chart type to use for your dataset?

I've developed a comprehensive classification of chart types based on their required data input format.

This decision tree is available as a poster, which you can order online or receive via email instantly!

Yan Holtz profile picture


A glimpse of the projects I've been working on


Feel free to contact me for any question. For open source projects, please open an issue or pull request on Github. If you want to follow my work, reach me on Twitter. Otherwise, send me an email at yan.holtz.data@gmail.com.

Github Twitter Mail