Tanmay is available for hire
Hire TanmayTanmay Chanda
Verified Expert in Engineering
R Shiny Developer
Delhi, India
Toptal member since January 23, 2026
Bio
Tanmay is an R and Shiny developer with over five years of experience. He is the author of three R packages on CRAN: rewind (undo and redo for Shiny), bones (content-shaped loading placeholders) and whence (where a dashboard number came from). He is a core developer of a production Shiny app for a global pharmaceutical company, built as a golem package with Docker, CI/CD and full test suites. Before that, he built marketing mix models and Shiny tools for media planning.
Portfolio
Acuity Analytics
RStudio Shiny, Docker, R, Git, Unit Testing
IPG
Python, R, HTML, CSS, JavaScript, SQL, Excel 365, MongoDB, Software Development...
Sirpi Products and Services Pvt
R, Python, RStudio Shiny, CSS, HTML, SQL, JavaScript, Excel 365, MariaDB...
Experience
- Excel 365 - 5 years
- CSS - 5 years
- R - 5 years
- RStudio Shiny - 5 years
- Python - 3 years
- HTML - 3 years
- MariaDB - 2 years
- SQL - 2 years
Work Experience
Senior Associate
2026 - PRESENT
Acuity Analytics
- Core developer of a production Shiny application for a global pharmaceutical company. Clinical study teams use it to build, review and keep an audit record of the metadata behind their study reports.
- Built the app as a modular R package with golem, shipped in Docker through CI/CD.
- Designed how the app finds and reuses duplicate records. Each merge gets an audit record.
- Built cross-record validation rules on shinyvalidate, with unit tests for each rule.
- Built a layer that checks and repairs metadata that an LLM generates, before it reaches the app.
- Added global search, a dependency table and a table-header editor.
- Wrote unit tests with each feature and an end-to-end shinytest2 suite.
Technologies: RStudio Shiny, Docker, R, Git, Unit Testing
Senior Associate
2022 - 2026
IPG
- Developed and maintained multiple R Shiny applications used by regional and global stakeholders for campaign optimization and planning.
- Built end-to-end R Shiny applications for media mix modeling, incorporating features like scenario analysis, dynamic charts, and download/reporting modules.
- Developed a nonlinear regression model using the Nonlinear Least Squares Levenberg-Marquardt (NLS LM) algorithm in R for optimizing media budget allocations and improving forecasting accuracy.
Technologies: Python, R, HTML, CSS, JavaScript, SQL, Excel 365, MongoDB, Software Development, Marketing Mix Modeling, Data Analytics, Marketing Analytics, Data Science, Data Scientist, Linear Regression, Regression Modeling, Media Mix Modeling, Bayesian Inference & Modeling, Marketing Mix
Data Science Engineer
2021 - 2022
Sirpi Products and Services Pvt
- Developed interactive R Shiny dashboards for business reporting and forecasting in operational contexts.
- Created regression-based forecasting and reporting tools to improve decision-making efficiency in operational contexts.
- Mentored junior team members on application development and ML best practices.
Technologies: R, Python, RStudio Shiny, CSS, HTML, SQL, JavaScript, Excel 365, MariaDB, Software Development, Data Analytics, Data Science, Data Scientist, Linear Regression, Regression Modeling
Project History
Biodiversity
An app that shows a map of Poland and animal sightings. Users can search for a species by its common name or biological name, and upon selecting an animal, they can see on the map where it has been spotted. The size of the bubble on the map indicates how frequently that animal has been sighted at that location.
CODE STRUCTURE
• Built using the Rhino framework for modularity.
• Implemented a Search feature, which also serves the purpose of displaying the species, and a Fuzzy Search feature using Reactable.
• Implemented a Map button using Leaflet.
• Implemented pop-ups with references to spotting and images.
• Integrated the Help button Modal using JavaScript.
• Applied styling changes using SASS.
CODE STRUCTURE
• Built using the Rhino framework for modularity.
• Implemented a Search feature, which also serves the purpose of displaying the species, and a Fuzzy Search feature using Reactable.
• Implemented a Map button using Leaflet.
• Implemented pop-ups with references to spotting and images.
• Integrated the Help button Modal using JavaScript.
• Applied styling changes using SASS.
rewind - undo and redo for Shiny
https://tenmeh.github.io/rewind/An R package on CRAN that adds undo and redo to any Shiny app with one line, rewind_enable(). Users step back with the keyboard, with buttons, or on a history rail. Rapid changes, such as a slider drag, become one step, and related changes can be grouped into one step. I am the sole author and maintainer.
Code: https://github.com/tenmeh/rewind
Code: https://github.com/tenmeh/rewind
bones - loading placeholders for Shiny
https://tenmeh.github.io/bones/An R package on CRAN. A Shiny output shows a grey placeholder in the shape of its content while it loads, in place of a spinner. The shape comes from the type of the output. The placeholder keeps the space, so the page does not move. When an output calculates again, the old content stays on screen, dimmed. I am the sole author and maintainer.
Code: https://github.com/tenmeh/bones
Code: https://github.com/tenmeh/bones
whence - where did this number come from?
https://tenmeh.github.io/whence/An R package on CRAN. The viewer clicks a number, a table row or a bar of a ggplot2 plot in a Shiny dashboard. whence splits the pipeline into its steps and shows how many rows each step removed, with code that reproduces the result. The pipeline does not need to be rewritten. I am the sole author and maintainer.
Code: https://github.com/tenmeh/whence
Code: https://github.com/tenmeh/whence
tanmai - chess positions from screenshots, with best moves
https://tanmai-103985161147.us-central1.run.appA Shiny app, built with golem, that reads a chess position from a screenshot, a FEN or a PGN and returns the best move from Stockfish. It also shows a "blunder radar": for a player of a given strength, it combines the Maia human-move network with Stockfish to show where that player is likely to go wrong. The app runs in Docker on Google Cloud Run, with CI/CD.
The board reading is also an R package, tanmai-r. It reads a position from a screenshot, a FEN, a PGN or a video of a game. It returns a tidy data frame and reports how confident the recognition is.
App: https://tanmai-103985161147.us-central1.run.app
Code: https://github.com/tenmeh/tanmai and https://github.com/tenmeh/tanmai-r
The board reading is also an R package, tanmai-r. It reads a position from a screenshot, a FEN, a PGN or a video of a game. It returns a tidy data frame and reports how confident the recognition is.
App: https://tanmai-103985161147.us-central1.run.app
Code: https://github.com/tenmeh/tanmai and https://github.com/tenmeh/tanmai-r
Education
2021 - 2023
Master's Degree in Computer Applications
Indira Gandhi National Open University (IGNOU) - New Delhi, India
Skills
Libraries/APIs
Ggplot2
Tools
Git
Languages
R, CSS, Python, HTML, SQL, JavaScript
Frameworks
RStudio Shiny
Paradigms
Unit Testing, Continuous Integration (CI)
Platforms
Docker
Storage
MariaDB, MongoDB
Other
Marketing Mix Modeling, Data Analytics, Marketing Analytics, Data Science, Data Scientist, Linear Regression, Regression Modeling, Excel 365, Software Development, Media Mix Modeling, Bayesian Inference & Modeling, Marketing Mix, GitHub Actions
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