Key Takeaways
Stop building custom tables. AG Grid ships with everything - virtualization, filtering, grouping, export, and inline editing - and it's free. The community edition alone covers most of what teams spend months building from scratch.
Custom cell editors follow one pattern: build a React component, expose getValue() via useImperativeHandle, pass it as cellEditor. That's the whole thing. The rest is just React.
Custom sorting is a comparator function with two values in and a number out. Sounds trivial. In practice, it solves sorting problems that alphabetical and numeric ordering can never handle correctly for domain-specific data.
I want to say something upfront that might sound obvious but apparently isn't, because I keep seeing teams do the opposite.
Don't build a data table from scratch in 2024. Just don't.
I've been on teams that did this. Everyone agrees it'll be "simple." A few weeks later someone's maintaining three hundred lines of sorting logic, a custom virtualization implementation that works okay on Chrome but behaves weirdly on Safari, and a filter system that the original developer understands but nobody else does. Then that developer leaves.
AG Grid exists. It's good. The community edition is free. Use it.
Okay, rant over. Let me actually show you how it works - and specifically how to extend it when the defaults aren't enough.
What Is AG GRID
AG Grid is a JavaScript data grid built for applications where data isn't just displayed - it's worked with. Filtered, sorted, grouped, edited, exported. There's a real difference between a library built for read-only display and one built for interactive data work, and AG Grid is firmly in the second category.
The performance is legit. Row virtualization runs by default, meaning it only renders what's visible in the viewport regardless of how many rows live in the dataset. Scroll through a hundred thousand rows and it stays smooth because it's not actually painting a hundred thousand DOM nodes. Most table components handle this badly or not at all.
Our React team at Innostax has shipped AG Grid into fintech dashboards with real-time data updates, healthcare record systems where clinical teams are filtering through thousands of patient entries, SaaS admin panels where operations people live in the grid all day. It holds up in ways that simpler libraries simply don't when the pressure increases.
What makes it worth learning properly isn't just the features - it's that the extension model is clean. Custom cell renderers, custom editors, custom sort comparators, custom filters - they all follow the same pattern. Build a thing, plug it in, AG Grid handles the lifecycle. Once that clicks, the whole library opens up.
Features Of AG GRID
Rather than walking through every feature - the AG Grid docs do that better than any blog post - here's what actually matters day-to-day:
Column definitions are everything. How a column sorts, filters, renders, whether it's editable, how it groups - all of it lives in the column definition object. The entire API kind of radiates outward from there.
Sorting and filtering are built in and actually good. Multi-column sort works. Complex filter combinations work. You configure them, you don't build them.
Grouping and aggregation are production-ready. Expandable row groups, aggregate functions on grouped data, subtotals - configuration, not custom code.
Cell renderers are just React components. Status badges, sparklines, progress bars, avatar + name combos - build a component, pass it as cellRenderer, Clean.
Virtualization is on by default. You don't turn it on. You'd have to turn it off, which you wouldn't want to do.
The community edition is free and genuinely capable. Enterprise adds Excel export, server-side row model, master-detail - useful things, but the free tier gets you surprisingly far before you need any of them.
Uses Of AG GRID
Short version: anywhere your users interact with tabular data rather than just glance at it.
Enterprise and internal tools - CRMs, ERPs, operations dashboards. People spending their workday in a grid need one that actually works under sustained use.
Fintech - Portfolio views, trading data, real-time price feeds. AG Grid handles fast-updating data without re-rendering the world on every tick.
Healthcare - Clinical data, patient records, scheduling. Filtering through thousands of records quickly isn't a nice-to-have when someone's trying to find a patient.
SaaS products - Almost every SaaS has a data table somewhere that users care about. AG Grid is consistently the right answer for that.
Analytics and reporting - The tabular half of a data product. Pair it with a charting library, and you've got a solid analytics UI without building either component yourself.
E-commerce and logistics - Inventory, orders, catalog management. High-volume datasets that operations teams work with constantly, not casually.
Genuinely - if there's a table in your app and users actually care about it, AG Grid is probably the right tool. The question is how much of it you need, not whether it fits.
Adding Custom Cell Editor
The built-in editors cover maybe 70% of real use cases. Text input, number input, select dropdown. They're fine.
The other 30% is where it gets interesting. A date range picker. A searchable multi-select. A custom input with validation logic that's specific to your domain. An editor that matches your design system instead of looking like it came from a different application.
Custom editors handle all of this. And the pattern, once you've seen it once, is genuinely straightforward.
Prerequisites
Before we begin, ensure that you have the following prerequisites:
A basic understanding of JavaScript and React (though you can use ag-Grid with other frameworks or plain JavaScript).
An ag-Grid project set up. If you haven't already, you can install it via npm or yarn:
Why go custom?
Three situations where the defaults stop working:
Unusual data types - Coordinates, color values, complex objects. The text input accepts anything but formats and validates nothing useful.
User experience - A purpose-built editor that fits your design system is better than a generic input. Users feel the difference even when they can't name it.
Domain-specific validation - Not "is this a number" but "is this a valid product code for our catalog." That logic belongs in the editor, not scattered through form handlers elsewhere.
Step 1: Set Up Your AG Grid Component
Create or locate GridComponent.js - wherever AG Grid lives in your application.
Step 2: Define the Custom Cell Editor
useImperativeHandle is the integration point. It exposes getValue() to AG Grid - that's how the grid retrieves the edited value when the user confirms a change. Everything else is plain React.
Step 3: Integrate the Custom Cell Editor with AG Grid
// GridComponent.js import React from 'react';
import { AgGridReact } from 'ag-grid-react';
import 'ag-grid-community/styles/ag-grid.css';
import 'ag-grid-community/styles/ag-theme-alpine.css';
import TextEditor from './TextEditor';
const GridComponent = () => {
const columnDefs = [
// Define your column definitions here
{ headerName: 'Custom Edit', field: 'customEditField', cellEditor: 'textEditor', }, ];
const gridOptions = {
frameworkComponents: { textEditor: TextEditor, },
};
return (
<div className="ag-theme-alpine" style={{ height: 400, width: 600 }}>
<AgGridReact
columnDefs={columnDefs}
rowData={yourData}
gridOptions={gridOptions} />
</div>
);
}; export default GridComponent;
cellEditor: TextEditor is literally the whole integration. AG Grid handles when the editor opens, when it closes, when it calls getValue(). You handle what the editor looks like and what it validates.
Handle the Edited Value
Use onCellValueChanged to react to confirmed edits - sync to an API, update local state, trigger downstream logic. AG Grid owns the editing lifecycle. You own what happens with the result.
Customize and Style
It's a React component. Style it however your project styles things. The goal is making it feel native to your application. Users shouldn't feel like they've entered "grid editing mode" - they should just be editing data.
Implementing Custom Sorting
Default sorting in AG Grid is alphabetical or numeric. For a lot of columns that's exactly right and you never think about it.
Then you hit a status column. Values are "Draft," "In Review," "Published," "Archived." Alphabetically, "Archived" sorts first. That's wrong in every way that matters to the people using your product.
Or part numbers: "A-9" and "A-10." Alphabetically "A-10" comes before "A-9." Again - wrong. Not wrong by some technical definition, wrong in terms of what users expect and need.
Custom comparators fix this. The API is minimal.
Step 1: Define a Custom Sorting Algorithm
export const customSort = (a, b) => {
const lengthA = a.length;
const lengthB = b.length;
if (lengthA === lengthB) {
return 0;
}
return lengthA < lengthB ? -1 : 1;
};
Sorting by string length here - contrived example, but the shape of the function is what matters. Two values in, a number out. Negative means a comes first, positive means b, zero means equal. Same contract as Array.sort. Replace the comparison logic with whatever your domain actually requires.
Step 2: Integrate Custom Sorting into AG Grid
import React from 'react';
import { AgGridReact } from 'ag-grid-react';
import 'ag-grid-community/dist/styles/ag-grid.css';
import 'ag-grid-community/dist/styles/ag-theme-alpine.css';
import { customSort } from './CustomSort'; // Import the custom sort function
const YourComponent = () => {
const columnDefs = [
{
headerName: 'Name',
field: 'name',
// Add the custom sort function to the column definition
comparator: customSort,
},
{ headerName: 'Age', field: 'age' },
// … other column definitions
];
const rowData = [
{ name: 'John Doe', age: 30 },
{ name: 'Jane Smith', age: 25 },
// … other row data
];
return (
<div className="ag-theme-alpine" style={{ height: '300px', width: '600px' }}>
<AgGridReact
columnDefs={columnDefs}
rowData={rowData}
/>
</div>
);
};
export default YourComponent;
In this step, we've added the comparator property to the column definition and assigned it the custom sort function (customSort). The comparator property allows us to specify a custom comparison function for sorting.
comparator in the column definition. That's the API. AG Grid calls it during sort and uses the result to order rows. Your custom logic runs exactly where it should - close to the data, in the column that owns it.
Step 3: Testing the Custom Sorting
Run the app, click the "Name" header, and watch rows sort by string length. Then replace the logic with your actual business rules. Status ordering, natural sort for alphanumeric strings, date range comparisons, priority tiers - all of it works through the same interface.
Conclusion
The best thing about AG Grid's extension model is that it doesn't ask you to fight the library to get what you want.
Custom sorting, custom editors, custom renderers - they all slot in cleanly. You build a thing, you plug it in, AG Grid does its job and calls your code at the right moment. There's no wrestling with internal abstractions or working around opinions baked into the library. It just… works the way you'd want it to.
That matters a lot in practice. Tools that are easy to extend tend to get extended. Teams actually build the specialized features their users need, rather than settling for "close enough." The grid ends up shaped around the product rather than the product being shaped around the grid.
If your application is data-intensive - and a lot of the most important applications are - AG Grid is genuinely worth learning properly. The ceiling is high, the defaults are solid, and when you need something specific, the path to building it is straightforward. That combination is rarer than it sounds.
About Innostax
Innostax specializes in managed engineering teams and was founded in 2014, and is headquartered in Framingham, Massachusetts. We establish engineering teams with accountability as a priority for both startups and enterprises, helping them achieve consistent software velocity with no customer churn.
Read more: Simplify Complex Data Handling with AG Grid in React.