01 · Design philosophy
Deconstructing the hashtag
Slack's mark is one of the few corporate logos that tells you what the product does before you read a word of marketing copy. Four colored droplets and four colored lozenges pinwheel into a shape that reads at once as a flower, a cluster of speech bubbles and an abstracted hashtag — and all three readings were intended. The 2013 original was a hashtag too: an eleven-color octothorpe rotated eighteen degrees, the very character that prefixed every channel name in the app. Pentagram did not replace it in 2019 so much as dismantle it. The octothorpe's four diagonals became the structural skeleton, two new shape types were added on top, and eleven colors were reduced to four. An evolution, not a revolution.
Design takeaway
Deconstruct the original. Keep its DNA, not its detail.
02 · Color psychology
Four colors, four conversations
Slack's palette works on two layers: the four colors of the mark itself, and the deep aubergine that holds everything together. Aubergine (#4A154B) is the sidebar surface every user sees the moment they open the app — warm, saturated and slightly mysterious in a category that defaults to white, grey or corporate blue. It is the most recognizable navigation surface in enterprise software, and it makes the product feel inhabited rather than utilitarian. The four logo colors each carry exactly one job. Red (#E01E5A) is urgency: mentions, notification badges, error states. Yellow (#ECB22E) is recognition: reactions, highlights, the star. Green (#2EB67D) is presence: the status dot beside a name. Blue (#36C5F0) is exchange: links, interactive elements, the send action. Together they encode the complete cycle of workplace communication.
Design takeaway
Give each color one job, then let them complete a cycle.
03 · Typography
From Sharpie scrawl to sharp edges
The Slack wordmark has always been set in lowercase — a deliberate rejection of all-caps corporate authority, and the reason the name reads as a voice rather than a statement. The 2013 version was a rounded, hand-drawn sans-serif that Fast Company called a "Sharpie scrawl": playful, but inconsistent across surfaces and short on the geometric discipline a global brand needs. The 2019 refresh replaced the scrawl with clean, structured letterforms in a custom variant of Lato, keeping the lowercase informality while gaining the precision required to reproduce crisply from a favicon to a billboard. The lowercase commitment survived; the scrawl did not. That trade — keep the spirit, refine the execution — is the same discipline Pentagram applied to the symbol.
Design takeaway
Keep the tone of voice; engineer the letterforms.
Color palette
One surface, four signals
Aubergine
Sidebar surface · the room where it happens
Slack Red
Urgency · mentions and alerts
Slack Yellow
Recognition · reactions and stars
Slack Green
Presence · available and online
Slack Blue
Exchange · links and the send action
04 · Historical evolution
From an eleven-color octothorpe to an eight-petal flower
Slack's visual history is short — roughly a decade and one decisive redesign — but each stage maps onto a turning point in the company's life. The first mark was product-led, built from the character that organised every conversation. The second is brand-led, built from the structure of collaboration itself.
2013
Slack launches in August with an eleven-color octothorpe rotated eighteen degrees in a plaid argyle pattern. The symbol is the hashtag that prefixes every channel name in the product.
2013–2018
Eleven colors and a precise rotation make the mark fragile — Slack itself called the variants "simply awful." Black-and-white, squared and icon-only versions multiply, and the identity fragments.
2019
On January 16, Pentagram's Michael Bierut and Slack's in-house team replace the plaid hashtag with four droplets and four lozenges in red, yellow, green and blue, anchored by the aubergine surface color.
2019
The redesign lands ahead of Slack's direct listing on the New York Stock Exchange — a scalable, single-color-safe identity built for public scrutiny.
2020
Salesforce acquires Slack for $27.7 billion, one of the largest software acquisitions in history. The four-color flower carries the brand intact into its next chapter.
Today
Aubergine sidebar, four-color flower, lowercase wordmark. A mark that models how separate people, channels and teams converge into one conversation.
05 · Design highlights
Why four colors survived the cull
The most consequential decision in Slack's 2019 redesign was the same one that defined eBay's 2012 refresh: what to keep. Pentagram stripped away the eleven-color palette, the eighteen-degree rotation, the plaid pattern, the rounded wordmark and the multiple logo variants — everything that made the old identity fragile. What survived was the octothorpe's structural DNA and four of its eleven colors. The result carries the same recognition in a fraction of the visual complexity, and the aubergine surface gives all of it somewhere to live.
Eleven colors became four
Every element that made the old identity fragile — the rotation, the plaid, the rounded scrawl, the multiple logo variants — was removed. The four colors that survived are not decoration; they are the brand.
Legible from 16px to a wall
No transparency, no overlap, no rotation. Four geometrically simple shapes that reproduce identically in print, on screen and in embroidery, with no twenty-page guidelines document needed to police usage.
A mark that models collaboration
Droplets read as speech bubbles, lozenges as message containers. Separate forms, woven together and bursting open — which is precisely what Slack does for the teams that use it.
06 · Brand application
One mark, every surface
Slack's identity has to survive a sidebar, an app icon, a sticker sheet, a mug and a conference wall. Because each of the four shapes is a high-contrast unit, the mark stays legible at any size and in any medium — and because it is designed to work in a single color, it never breaks when ink is limited. The aubergine surface gives every application a room to sit in; the four colors give each surface something to say.
Brand background
From a failed game to a $27.7 billion conversation
Stewart Butterfield had already co-founded Flickr before he started the company that became Slack. In 2009 he co-founded Tiny Speck, a game studio whose project Glitch was built on a janky internal chat tool assembled on top of IRC so a distributed team could talk to itself. When Glitch shut down in November 2012, the team realised the communication system was worth more than the game. Slack — the Searchable Log of All Conversation and Knowledge — launched in beta in August 2013 and publicly in February 2014, reaching a billion-dollar valuation within eight months. It listed on the New York Stock Exchange in 2019, and Salesforce acquired it in December 2020 for $27.7 billion. The playfulness, the refusal to look like traditional enterprise software and the commitment to making work feel human all trace back to a team of game developers who wanted a better way to talk to each other.
Authoritative sources
- Say hello, new logo — Slack Blog
- Pentagram deconstructs Slack's hashtag logo — Dezeen
- Slack's new logo ditches the beloved plaid hashtag — Fast Company
- Slack has a new logo because the last one was 'simply awful' — CNBC
- Slack brand guidelines — official PDF
- Say hello to Slack — TechCrunch, 2013
- Stewart Butterfield — Wikipedia