How to Make WhatsApp Web Look Like Slack

If WhatsApp Web is your daily work tool — which it is for millions of professionals, especially in markets where WhatsApp Business is the default channel — there's a good chance you've looked at Slack on a colleague's screen and felt a small pang. Slack just looks more like a work tool. The dark aubergine sidebar. The clean, focused chat area. The implicit message that "this is where serious things happen."

You can get most of that visual feel on WhatsApp Web in about five minutes. Not the threaded replies or workspaces — that's a structural difference, not a theming one — but the visual identity that makes Slack feel like work. Here's how.

A Quick Honest Note Before We Start

Slack's design strength isn't its color palette. It's its information architecture — channels, threads, status indicators, workspace switching. None of that is achievable through theming, because WhatsApp Web doesn't have those features.

What you can recreate is Slack's visual identity: the aubergine sidebar, the clean typography, the calm professional palette, the absence of clutter. That's what this post covers. If you went in expecting full Slack replacement, this won't deliver it — and frankly no Chrome extension will. But if you want WhatsApp Web to feel like a serious work tool instead of a chat app, that's very achievable.

Step 1: Install the Extension

You'll need WhatsApp Web Customizer for this:

👉 Install WhatsApp Web Customizer

Free, open source, 30 seconds to install. Pin it to your toolbar.

Why this specific extension? Slack's distinctive look comes from its two-tone palette — a dark sidebar contrasted against a light main area — plus its typography. Pulling that off requires editing the sidebar separately from the chat window, separately from the chat list, separately from accent colors. Most WhatsApp Web extensions don't let you change those independently.

Step 2: Switch to a Slack-Style Font

Slack uses Lato as its primary typeface — a clean, professional, friendly sans-serif. It's what gives Slack messages their distinctly "this is workplace communication" feel.

Open the extension popup, click the Typography tab, and pick:

Lato — yes, the actual font Slack uses. Free and available in the extension's 500+ font library.
Inter — slightly more neutral alternative if Lato doesn't suit you.
Source Sans Pro — another professional sans-serif option in the same visual family.

Set the font size to something comfortable for long sessions — Slack defaults to a slightly larger, more readable body text than WhatsApp's default. Bump WhatsApp Web up by 1–2 size steps to match.

Step 3: Build the Slack Color Palette

This is where the transformation happens. Open the Themes tab, click Create (or the Custom tab → New Theme), and you'll land in the editor.

Slack's signature look is built around a dark sidebar against a light chat area — the inverse of most chat apps' design. Here's the palette:

Sidebar (the Slack-signature aubergine)

Classic Slack aubergine: #3F0E40
Or Slack's newer dark mode sidebar: #1A1D21

Sidebar text and inactive items

Soft purple-white: #BCABBC (for the aubergine sidebar)
Or off-white: #D1D2D3 (for the dark mode sidebar)

Active chat in sidebar

Slightly lighter aubergine: #350D36 background with white text
Or for dark mode: #1164A3 (Slack's signature blue highlight)

Main background (chat area)

Clean white: #FFFFFF for light mode
True dark gray: #1A1D21 for dark mode

Sent chat bubbles (your messages)

For the most Slack-accurate look, Slack doesn't use distinct bubbles — messages are stacked flat with the author name at top. WhatsApp Web requires bubbles, so use #F8F8F8 in light mode (barely-visible separation) or #222529 in dark mode.

Received chat bubbles (their messages)

Same as sent: #F8F8F8 light / #222529 dark. Slack treats all messages visually equally.

Text color

Near-black: #1D1C1D for light mode
Off-white: #D1D2D3 for dark mode

Accent color (links, mentions, active states)

Slack blue: #1164A3
Or the brighter modern Slack blue: #1264A3

Apply these one by one in the editor. The most visually transformative moment is when you change the sidebar to aubergine — that single change makes WhatsApp Web immediately feel like Slack.

Step 4: Strip the Clutter Slack Doesn't Have

Slack's sidebar is purposeful — channels, DMs, threads, mentions. It doesn't have Status, Archive folders, or Channels-in-the-WhatsApp-sense cluttering the view.

Turn on Minimal Mode in the extension. This hides:

Archive
Status
Locked chats
Channels

The result feels much closer to Slack's intentional sidebar — just the conversations you actually engage with.

Step 5: Set the Right Background

Slack's chat area is always clean. No wallpapers, no patterns, no doodles. Just a calm solid background that puts the messages front and center.

Light mode: solid #FFFFFF for the chat window, with the aubergine sidebar
Dark mode: solid #1A1D21 for the chat window, with the darker sidebar variant

The extension lets you set the chat window, sidebar, welcome screen, and chat list backgrounds independently — which is exactly what you need to pull off Slack's two-tone palette.

Step 6: Save It (Or Build It as JSON)

Once it looks right, save your theme. It'll appear in the Custom tab — one click to apply, one click to switch back.

For teams that all use WhatsApp Web for work: the JSON export feature is genuinely useful here. Click Download Template, edit the JSON with the Slack palette above, save the file, and share it with your team. Everyone can drop the same JSON into their extension and have a consistent visual setup — a small but real productivity win for remote teams.

We covered the full JSON workflow in our themes installation guide.

Pair the Theme With Slack-Style Productivity Habits

Visual changes go a long way, but to really make WhatsApp Web feel like a work tool, a few habits help:

Set up quick replies for the messages you send constantly ("On it", "Will follow up", "Thanks, received"). Slack culture is short-and-snappy responses. WhatsApp Web Customizer's quick reply bubbles let you preset those.
Pin your top 3 work chats — Slack-style "starred channels at top."
Mute everything that isn't time-critical. Slack users mute aggressively; WhatsApp Web users tend not to. Right-click any chat or group → Mute.
Enable the privacy blur for sensitive client conversations — useful when you're screen-sharing in a meeting and don't want WhatsApp visible.

We wrote a full guide on WhatsApp Web tips for remote and professional work if you want to go deeper.

Why You Need This Extension (And Why Others Can't Do It)

Slack's two-tone aubergine-and-white palette is a hard test for any WhatsApp Web theming tool. You need to color the sidebar one way, the chat area another, the chat list a third, the accent a fourth. They're four different surfaces that need four different colors.

The closest competitor on the Chrome Web Store only offers a gradient start color, a gradient end color, and two opacity sliders. There's no way to recreate Slack's look with that — you can't have a dark sidebar and a light chat area, because everything is tied to the same gradient.

WhatsApp Web Customizer was built so users get full control over each surface independently. Real-time preview, JSON import/export, your own custom fonts if 500+ built-in ones aren't enough. It's why MakeUseOf, TechPP, and other tech publications have featured it throughout 2025–2026 — and why recreating Slack on WhatsApp Web is actually possible today.

Your Slack Theme Sticks

Once you've built and saved the theme, it stays. Reload WhatsApp Web, close the tab, restart your browser, restart your computer — the theme reapplies automatically. You don't need to log in, sync, or back anything up.

Going Further

A few directions worth exploring:

Build matching light and dark Slack variants — Slack users typically use both, switching by time of day. The extension makes it easy to save both and switch with one click.
Try other looks — if Slack isn't quite right for you, see how to make WhatsApp Web look like Telegram, how to make WhatsApp Web look like iMessage, or how to make WhatsApp Web look like Discord.
Set up the full professional workflow — combine the Slack theme with everything in our WhatsApp Web for remote work guide for a complete setup.

The Bottom Line

WhatsApp Web isn't going to ship Slack-style theming natively. Meta hasn't built a real customization system in over a decade and isn't likely to start now. The only way to make WhatsApp Web feel like a serious work tool — aubergine sidebar, clean typography, calm professional palette — is a Chrome extension and about five minutes of color picking.

It won't give you channels or threads, because those are structural Slack features that can't be recreated with theming. But it will give you Slack's visual identity, which is most of what makes Slack feel like Slack in the first place.

👉 Install WhatsApp Web Customizer and build your Slack theme. If your team is on WhatsApp Web for work, share the JSON file so everyone has the same setup — our Discord is a good place to share team themes you've built.