What was Slack's launch strategy?
Slack reached the public in four widening steps over 13 months. After some prototyping in December 2012, work formally kicked off on 8 January 2013, when co-founder Stewart Butterfield showed the eight-person team at Tiny Speck a slide with a release timeline. The stages ran from a prototype good enough for the team to use full time, to an alpha for trusted friends, to a version good enough to charge money for. That account comes from Building Slack, a history written in 2024 by Ali Rayl and Johnny Rodgers, two of Slack's original employees.
Here is how the plan played out, from Butterfield's 2015 interview with First Round Review and the Building Slack posts:
| Date | Stage | What happened |
|---|---|---|
| 8 Jan 2013 | Kick-off | Eight people start work on Slack after shutting down the game Glitch |
| 14 Feb 2013 | Internal use | The team moves its own work from IRC to Slack |
| May 2013 | Alpha with friends | Friends at roughly six to ten companies start using it |
| 13 Aug 2013 | Preview release | Public sign-up form; 8,000 sign-ups on day one, 15,000 within two weeks |
| 12 Feb 2014 | Public launch | Billing switched on; the first live payment goes through |
The original slide was faster. It put a private beta in mid-April 2013 and an open beta at the end of May. The open-beta stage, described as good enough for the general public with disclaimers, is the one Rayl and Rodgers say Slack was nearly ready for six months in, and it arrived in August as the preview release.
Who were Slack's first 6 to 10 companies?
They were companies where the Slack team had friends. Butterfield told First Round Review that the team begged and cajoled friends at other companies to try Slack and give feedback, and started with roughly six to ten companies found that way. The interview names Cozy, which sells rental management software, and the music service Rdio. Building Slack names Rdio, Medium and ThatGameCompany as early testers still using Slack by summer 2013.
The ask was large. According to Rayl and Rodgers, Butterfield suggested each team quit email for a week and do all internal communication in Slack, because the test would not work if some people stayed on email.
Rdio stood out because it was much bigger than Slack's own team. The two accounts give different sizes: Butterfield said in 2015 that use spread to all 120 people at Rdio, while the 2024 history says Rdio had over 300 people at the time. Either way, Slack had only been used by eight people, and the team had guessed it would top out at about 150. At Rdio, new hires could not tell which of the many channels to join, so Slack added a description and a member count to each channel in the list. Testers also started adding prefixes to channel names to group them.
Butterfield described the method as sharing Slack with progressively larger groups, fixing what broke, then adding more teams.
Why did Slack call it a preview release instead of a beta?
Slack avoided the word beta because of what it signals. Butterfield told First Round Review that the preview was essentially a beta, but "we didn't want to call it a beta because then people would think that the service would be flaky or unreliable."
Rayl and Rodgers give the reasoning. Slack was asking companies to move all their internal communication into it, and few would do that for software labelled buggy. The team had also used Slack exclusively for nearly six months, so it already worked well.
A memo Butterfield sent the team on 31 July 2013 set the targets. The Preview Release went live on 13 August 2013 with a new website and a sign-up form that promised an invite when Slack had capacity.
| Memo plan (31 July 2013) | What happened | |
|---|---|---|
| Sign-ups | At least 1,000, of which 200 qualified leads | 8,000 on day one, 15,000 within two weeks |
| Invites | About 200 new teams over six weeks | The team had to invite everyone, in batches |
| Length | No fixed timeline, Butterfield said in 2015 | About six months, August 2013 to February 2014 |
Butterfield told First Round that from August 2013 to February 2014 the team worked through those first 15,000 sign-ups, and more, improving the new-user experience as it went. First Round credits a press blitz based largely on the team's prior experience, and Butterfield estimated that a published article is only about 20% of media success; the other 80% is people posting about it. Many preview teams had earned credits that, according to Building Slack, paid for their first year once billing started.
How did Slack answer every ticket and tweet?
Slack answered every piece of feedback, from the alpha onwards. The volumes grew, but the rule stayed:
| Period | Volume and team | How it worked |
|---|---|---|
| Alpha, 2013 | A handful of friendly teams | A /feedback command sent reports into a #support-hose channel; fixes were often shipped and confirmed to the reporter in under an hour, dozens of times a day |
| Summer 2013 | Too much for Ali Rayl and Butterfield alone | Two former Glitch colleagues rehired to keep the promise that a human would read and answer every support request |
| Spring 2014 | Volume not given | Butterfield and Rayl each spent at least two hours a day tweeting from @SlackHQ |
| Early 2015 | About 8,000 Zendesk tickets and 10,000 tweets a month | All answered, Butterfield said; First Round put customer support at 18 people, with an overlapping group of 6 on Twitter around the clock |
Sources: Building the Slack MVP, Good enough, You asked: Release Notes and the 2015 interview. In the alpha, the team responded to each message personally, often directly from Butterfield. By the public launch, quality assurance and support had been merged into one customer experience group of three people.
The replies paid off in public. Early users tweeted their thanks and Slack replied. Rayl and Rodgers call that word of mouth on Twitter a major driver of new teams, so much so that the team collected those tweets on a Wall of Love page. First Round reports that tweets and tickets were tagged and stored in their own Slack channels, and Butterfield said good ideas were posted every day to a channel where the team discussed new features.
What is Slack's 2,000-message rule?
The 2,000-message rule is a threshold Slack chose from experience. In the February 2015 interview, Butterfield said the team decided that any team that had exchanged 2,000 messages in its history had really tried Slack, based on which companies stuck with it and which didn't. The figure Butterfield gave for those teams: "after 2,000 messages, 93% of those customers are still using Slack today."
- Size of the bar. About 10 hours of messages for a team of around 50, or roughly a week for a typical team of 10.
- Why it mattered. First Round reported that more than 90% of people who filled in the form to start a team never invited anyone or started using Slack. Of roughly 220,000 teams created, upwards of 30,000 were active, with close to 250,000 daily active users.
- How it was used. With the number fixed, the team could work on ways to get more teams across it.
Read the 93% carefully. It is company-reported, given in one interview in 2015, and the article states no time window, no cohort dates and no definition of still using. It describes teams that already passed the bar; it does not show that sending 2,000 messages caused teams to stay. Building Slack adds an earlier signal from 2013 usage data: teams needed a critical mass of about 8 people to stay active.
Butterfield's broader point was that each company has to define its own activation and retention numbers, because products and users differ.
Slack's launch strategy for a 1 to 5 person B2B team
You can run the same sequence with one product and a handful of customers. The steps below are our suggestions, scaled down from Slack's numbers; Slack's own figures are labelled.
Write a five-line stage timeline
Copy the shape of Butterfield's slide: good enough for us, for trusted friends, for strangers, for the public with disclaimers, and to charge money for. Put a date on each line and share it with the team.
Recruit 6 to 10 friendly companies
Ask founders you know, and include at least one company bigger than your usual customer, as Rdio was for Slack. Ask for a one-week all-in test. If your network runs short, Siela's AI SDR can track keywords and competitors on LinkedIn and X and turn people who post about the problem into leads.
Build one feedback pipe and answer everything
Send every form entry, email and mention into one shared channel. Reply to each one, fix small things the same day, and tell the person when the fix ships. Tag requests so you can count them.
Open a preview with a written target
Slack's memo aimed for at least 1,000 sign-ups, 200 qualified, and 200 teams invited over six weeks. A small B2B team might aim for 100 sign-ups, 20 qualified and 20 teams in six weeks. Promise an invite when you have capacity, then invite in batches.
Find your own 2,000-message number
List every account from the last six months. For each, count your core action (reports run, invoices sent, messages exchanged) in its first 30 days and mark whether it is active today. Look for the count above which most accounts stayed. With a few dozen accounts, treat it as a working guess.
For the outreach side of steps 2 and 4, see our guides to founder-led sales and buying signals for small teams.
Frequently asked questions
When did Slack launch publicly?
Slack launched publicly on 12 February 2014, according to Building Slack, the history written by early employees Ali Rayl and Johnny Rodgers. That was 13 months after work formally kicked off in January 2013, about nine months after the early alpha reached friends' companies, and six months after the preview release opened on 13 August 2013. Billing went live on launch day.
Why did Slack call its beta a preview release?
Stewart Butterfield told First Round Review in 2015 that the team avoided the word beta because people would expect a flaky, unreliable service. Rayl and Rodgers add that Slack was asking companies to move all internal communication into it, and the team had used it exclusively for nearly six months, so it already worked well.
How many people signed up for Slack's preview release?
About 8,000 people signed up on the first day and 15,000 within two weeks. A memo Butterfield sent the team on 31 July 2013 had aimed for at least 1,000 sign-ups, 200 of them qualified, and planned to invite about 200 teams over six weeks. The team revised the plan and worked through the sign-ups in batches until the February 2014 launch.
What does Slack's 2,000-message metric mean?
In a 2015 interview, Butterfield said Slack treated any team that had exchanged 2,000 messages as having really tried the product, a line drawn from experience of which companies stayed. At the time, 93% of those teams were still using Slack. For a typical 10-person team that was about a week of messages. The interview gives no time window or cohort dates.
Which companies tested Slack before its launch?
First Round Review names Cozy, a rental management software company, and the music service Rdio. Building Slack names Rdio, Medium and ThatGameCompany. Rdio was one of the biggest tests: Butterfield put it at 120 people in 2015, while the 2024 history says over 300. Its many channels led Slack to add a description and member count to each channel.
Sources
- First Round Review: From 0 to $1B, Slack's Founder Shares Their Epic Launch Strategy (26 Feb 2015)
- Building Slack: Day 1 (Ali Rayl and Johnny Rodgers) (14 Feb 2024)
- Building Slack: Building the Slack MVP (19 Feb 2024)
- Building Slack: Good enough to be tried by the general public (29 Feb 2024)
- Building Slack: You asked: Release Notes (26 Feb 2024)
- Building Slack: Preparing for launch (4 Apr 2024)
- Building Slack: Year 1 (24 May 2024)
- Building Slack: About (checked 20 Oct 2026)