Mastering Retool Data Visualization: Complete Chart Guide

Hieu Nguyen
April 16, 2025
15 mins
Mastering Retool Data Visualization: Complete Chart Guide

Retool data visualization makes it easy to turn raw data into insights—without tools like Tableau

Retool charts, built on Plotly.js 2.34, give you 15 different chart types - from simple bar charts to complex pie charts - at a lower cost. Your data summaries through simple aggregations or interactive visualizations become easier with Retool’s chart-building features. Raw data transform into meaningful insights quickly.

Creating perfect visualizations can be challenging with different data types and transformation needs. This complete guide will help you become skilled at using Retool charts, from simple setup to advanced combinations. Let’s explore how to turn your data into compelling visual stories!

Understanding Retool Data Visualization Basics

Retool’s chart components run on a unified architecture powered by Plotly.js version 2.34. This makes them both flexible and powerful. Many visualization tools hide complexity behind limited options. Retool takes a different approach by exposing Plotly’s full potential and adding user-friendly features.

Key components of Retool’s visualization system

Retool charts have two basic objects at their core: data and layout. Your actual information and chart configuration live in the data object. The layout object manages appearance settings like titles, legends, and margins. This matches Plotly’s native architecture, so developers can use their existing knowledge.

These components form the foundation of most Retool charts:

  • Data source - The query, transformer, or JavaScript that supplies your visualization data
  • Add-ons - Extra elements like titles, toolbars, legends, and tooltips that improve functionality
  • Axis controls - Settings that determine how axes display and format values
  • User interaction settings - Options that control how users can select and manipulate data points

Retool shows the .selectedPoints array property when users interact with charts. This enables dynamic filtering and updates throughout your application.,

Available chart types and their purposes

Retool gives you 15 differents chart types. Each serves specific visualization need:

  • Bar Chart - Compares values across categories
  • Bubble Chart - Shows relationships between three variables
  • Funnel Chart - Visualizes sequential process stages
  • Heat Map - Displays data density across two dimensions
  • Line Chart - Tracks changes over time or sequences
  • Mixed Chart - Combines multiple chart types on one canvas. You can merge different visualizations like Line, Bar, Scatter, Waterfall
  • Pie Chart -  Shows proportional composition of a whole
  • Plotly JSON Chart - Creates custom visualizations using raw Plotly code
  • Sankey Chart - Visualizes flows between nodes (perfect for budgets)
  • Scatter Chart - Plots individual data points to show correlations
  • Sparkline - Creates compact trend indicators
  • Stacked Bar Chart - Shows composition and totals together
  • Sunburst Chart - Displays hierarchical data as nested rings
  • Treemap - Visualizes hierarchical data as nested rectangles
  • Waterfall Chart - Shows how positive and negative values contribute to a total

This collection helps you find the right visualization to tell any data story

How data flows into Retool charts

Creating effective visualizations requires understanding Retool’s chart system data flow. Charts can get data from three main sources: queries, transformers, or JavaScript.

The system works simply. You select a query or transformer in the Data source field and Retool fills your charts. Next, you map specific fields from your data to chart attributes. Series-based charts need X/Y data pairs, while categorical charts use Labels/Values pairs.

Your data source fields’ names appear in legends and tooltips by default. Retool picks chart names based on your data structure and grouping choices.

Built-in aggregation functions make Retool charts powerful. You can apply Sum, Average, Count, Min, Max, and seven other aggregation types when multiple Y values exist for one X data point. The Group by property segments data across dimensions. This works great for showing metrics like revenue by product or headcount by team.

JavaScript transformers help prepare data for your chart in complex scenarios. This gives you complete control over turning raw data into polished visualizations.

These fundamentals will help you build charts that display data accurately and tell compelling visual stories.

Preparing Your Data for Visualization

The quality of your data preparation makes or breaks effective visualizations with Retool charts. Bad data leads to poor charts - even the most sophisticated visualization can’t save poorly organized information.

Structuring data for optimal chart rendering

Your data must follow specific patterns for Retool charts to display correctly. We organized chart data in an array of objects format, where each object shows a single data point or record. The key-value pairs in these objects become your axis values and data points.

These best practices will help you design your data structure:

  • Fetch only necessary fields - Skip SELECT * statements since they pull extra data that increases payload size
  • Limit data volume - Your browser slows down with charts showing thousands of points
  • Use consistent data types - This matters most for dates and numbers
  • Provide unique identifier - Each point needs its own distinct identifier

A well-laid-out dataset has date, category, and value fields - ideal for time-series visualizations that break down by category.

Using queries and transformers as data sources

Retool charts can get data from three main sources: queries, transformers, or JavaScript. Queries link straight to your data sources, while transformers help reshape and prepare that data for visualization.

These query optimization techniques boost performance:

  • Run queries on demand instead of loading all data automatically
  • Apply filters server-side to shrink dataset size before client delivery
  • Use server-side pagination with large datasets to speed up loading

Transformers shine at getting query results ready for visualization. These reusable Javascript code blocks can filter, sort, combine, and reshape your data. To name just one example, see how a transformer might filter unwanted records, normalize values, or merge multiple data sources.

A transformer example that filters based on user input:

const filteredData = formatDataAsArray(data).filter(
	obj => obj.first.includes({{ search.value }})
	);
return filteredData;

Data aggregation techniques

Built-in aggregation capabilities in Retool charts automatically summarize your data. This feature helps when you have multiple Y values for a single X data point.

The available aggregation methods are:

  • Sum - Totals all numeric values
  • Average - Calculates the mean of numeric values
  • Count/Count distinct - Tallies items in each group
  • Min/Max - Finds extreme values in each group
  • Median/Mode - Identifies central tendencies
  • Standard deviation - Measures data dispersion
  • First/Last value - Returns boundary values

The Group by property lets you combine serial data across multiple dimensions. This works great to visualize metrics like revenue by product over time.

Handling dates and time series data

Time-based visualizations need extra cate with date formatting and time zones. Retool might not recognize your data fields as actual at first, so you’ll need to transform them.

Here’s how to format dates properly:

  1. Use Moment.js (pre-loaded in Retool) to convert string dates to proper date objects
  2. Apply consistent formatting across all date values
  3. Think about time zone differences when showing date-time data

This code formats dates for the x-axis:

.map(d => moment(d).format("YYY-MM-DD"))

You can also filter time series data with components like daterangepicker. Users can adjust date ranges dynamically, creating interactive visualizations that respond to their selections.

Well-prepare data are the foundations of effective Retool charts. Structure your data carefully, use queries and transformers wisely, apply the right aggregation, and handle dates properly. This approach will help you create meaningful visualizations.

Building Your First Retool Charts

Let’s get hands-on and create real visualizations with Retool charts. We’ll move from theory into action.

Setting up a simple bar chart

You can create your first bar chart by dragging the Bar Chart component onto your canvas. The Bar Chart shows data in vertical bars and works great to compare categorical data. The inspector panel lets you select your data source and map your fields by setting X and Y data values.

Your bar chart’s appearance improves with these properties:

  • barGap - Controls spacing between groups (0-1 range)
  • barGroupGap - Adjusts spacing between bars within groups
  • barMode - Determines how multiple data series show up
  • barOrientation - Sets vertical or horizontal display orientation

The isHiddenOnMobile property helps you create mobile-friendly visualizations. The toolbar configuration gives users ways to interact with your char through zoom, pan, and select options.

Creating interactive pie charts

Pie charts show proportional data within a whole really well. Add the Pie Chart component to your canvas and set up your data source. Under “value labels”, pick the field that creates labels for each segment.

The pieDataHole property turns your pie chart into a donut chart by setting the hold depth from 0-1. You’ll likely need a dataset with an aggregation method like Sum to count category occurrences.

To name just one example, see how device manufacturers from an API response need raw data transformation into an array of objects with manufacturer names. Retool then adds up the occurrences of each manufacturer automatically.

Implementing line charts to track trends

Line charts are perfect at showing data changes over time. Add the Line Chart component, pick your data source, and set X data (usually dates) and Y data (values to track). Different lines appear for various categories with the “Group by” setting.

Line Charts come with these helpful properties:

  • chartType - Set to “line” by default
  • clearOnEmptyData - Controls display with empty datasets
  • title - Adds descriptive text above the chart
  • xAxis/yAxis - Controls axis appearance and behavior

Users can focus on specific time periods with the rangeSlider property, which makes finding trends easier.

Chart data series names and their sources

Your data source fields automatically provide chart data series names that show up in legends and tooltips. Note that scripts working with components use a copy of the components object. Setting properties like chart1.dataseries[x].visible = false won’t change the component.

You should create a new dataseries variable with your chart’s Plotly JSON field value. Make your changes and return that dataseries to update the chart. When transformers serve as data sources, series names come from your data structure and grouping choices.

The Mixed Chart component lets you blend two different chart types. This makes it possible to show related metrics with different scales or formats in one view.

Customizing Chart Appearance and Behavior

Retool charts reveal their true potential when you become skilled at customization. Your basic visualizations can evolve into professional, interactive dashboards that have a real effect.

Styling options for professional visualizations

You can create visually striking charts in Retool through multiple methods. The Spacing and Appearance sections in the Inspector let you adjust your visualization’s presentation. The Styles setting offers deeper customization to match your brand identity with color, fonts, and text styles.

Chart backgrounds can change through the plot_bgcolor and paper_bgcolor in Plotly JSON mode. This technique creates transparent backgrounds that blend naturally with your application design:

{
	"paper_bgcolor": "rgba(0,0,0,0)",
	"plot_bgcolor": "rgba(0,0,0,0)"
}

Adding interactive elements

Static charts become powerful analytical tools with interactivity. The .selectedPoints array property activates when users interact with your charts. Your charts can filter, transform, or update other components based on selections.

The system also lets you configure event handlers for various user actions:

  • Select
  • Clear
  • Legend click/double-click
  • Hover/Unhover

Your charts turn into dynamic data entry points by connecting these events to queries or transformers.

Implementing tooltips and hover effects

Tooltips add context and detail without visual clutter. The Add-ons setting supports their addition along with legends, data labels, and toolbars.

Different chart types need different tooltip customization approaches. Pie charts require “hovertemplate” property adjustment:

"hovertemplate": "<b>%{label}</b><br>Value: %{value}<extra></extra>"

Line charts can display multiple series in one tooltip. Just enable the ‘Use array’ checkbox and pass custom strings for each data point.

Mobile-responsive chart design

Mobile-friendly visualizations need careful design consideration. The aspectRatio property helps maintain proper proportions on different screen sizes. Most designers use like 1.33 (4:3) or 1.78 (16:9).

Retool’s standard chart components don’t resize automatically for smartphones. You might want to:

  • Use container components with responsive settings
  • Set visibility conditions based on screen size
  • Create separate mobile-optimized views

A well-designed visualization communicates effectively on any device. Charts should stay simple and focused for mobile users.

Advanced Charts Techniques and Combinations

You’re ready to explore advanced techniques after learning the simple aspects of Retool charts. These methods help create sophisticated visualizations that lead to better decisions.

Which of the following chart types enables you to combine two charts?

The Mixed Chart component serves as Retool’s solution to combine different chart types on a single canvas. This tool displays data on an x-axis with multiple y-axes and helps visualize relationships among several datasets effectively. To cite an instance, revenue bars can appear with customer growth lines - showing context that separate charts would miss.

The Mixed Chart lets you do more than standard charts:

  • Compare metrics with different scales (revenue vs. percentage growth)
  • Present related data in complementary formats
  • Reduce dashboard clutter by consolidating visualizations

Creating custom Plotly JSON charts

Retool’s Plotly JSON Chart component offers ultimate customization. This advanced option builds charts with raw Plotly JSON structured data that standard presets might not cover.

The component needs two key elements:

  1. plotlyDataJson - Contains your data in Plotly JSON format
  2. plotLayoutJson - Controls appearance settings like titles and margins

Custom charts give you access to advanced features like annotations, trendlines, and integrated UI buttons. The tool exposes API methods like plotlyJsonChart.scrollIntoView() and plotlyJsonChart.setHidden() that provide programmatic control.

Building dynamic dashboards with multiple charts

Interactive dashboards come alive as charts respond to user interactions. Charts update automatically when users select data points in connected visualizations.

Business intelligence dashboards can connect multiple data sources and show complex relationships across sales, revenue, and marketing metrics. Teams track KPIs and make informed decisions without switching between different tools.

Advanced Retool charts shine brightest through their shared capabilities. They create a unified analytics experience that turns raw data into applicable information.

Conclusion

Retool charts offer powerful tools that turn complex data into meaningful visualizations at a fraction of traditional BI solutions’ cost. These charts become vital parts of any evidence-based application through proper data preparation, thoughtful customization, and strategic implementation of interactive features.

The charts’ flexibility lets you combine different types and create custom visualizations with Plotly JSON that meet your specific needs, whatever the complexity. Professional-looking dashboards work smoothly on all devices thanks to built-in mobile responsiveness and extensive customization options.

Note that successful data visualization requires clean, well-laid-out data and clear objectives. You should begin with simple charts, become skilled at the fundamentals, and then explore advanced features like Mixed Charts and custom Plotly implementations. Your path to creating perfect visualizations with Retool charts starts here. Retool data visualization gives your team a fast, cost-effective way to build powerful insights into your app or dashboard experience.

Build Powerful Internal Tools with Retool

At Retoolers, we help businesses create custom dashboards, admin panels, client portals, and full workflow automation solutions using Retool. From idea to execution, we’ve got the skills to make it happen.

Let’s build something great together — contact Retoolers today.

Hieu Nguyen
Retool Developer

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