Slack is one of the most interesting and promising SaaS software companies. And it's positioned well as a new new commmunications operating system for the modern workplace. Slack already serves 1B+ messages a week and is quickly gaining adoption at the world's most successful companies (as well as almost every new startup).
As a result, it's a fun company for any aspiring (or current) product managers to study up on. Below, we've assembled a data pack of core Slack engagement, retention and monetization metrics. If you're going through product management interviews at SaaS companies (or even Slack itself), hopefully these metrics can serve as helpful benchmarks when you're preparing.
Data in this post came from Slack S-1 filing, Slack's PR filings and other publicly available SaaS metrics. Occasional assumptions are made and cited where public data is not available.
Key Slack metrics covered:
Consider the following questions that might come up in a product management interview for a SaaS company:
In each of the aforementioned interview questions, understanding key SaaS metrics helps tremendously. Without a baseline of knowledge, you won't 1) understand what average or best-in-class metrics look like and 2) might be caught off guard by specific lingo, terms or metrics that SaaS companies pay close attention to.
To start, it can be helpful to review some "point in time" metrics that Slack has released in advance of their eventual 2019 IPO. Ultimately, these metrics are less helpful for understanding company trajectory; the time series data below will be much more helpful for that.
However, these metrics help crystallize how big Slack has become, despite it's relatively short existence so far. The average paying user spends 90 minutes per day in the product, 1B+ messages flow through it a week and half a million organizations already use the product.
Daily average users (DAU) is a common metric that's been popularized by consumer tech companies like Facebook, Twitter and Zynga.
It's far from a perfect metric. However, it provides a helpful proxy of determining the volume of daily engagement and can be helpful to spot high level trends when plotted as a time-series.
As shown below, Slack's DAU metrics have been incredibly strong - and this reflects two key factors: 1) Slack's adoption amongst tech companies and startup has been rapid and 2) the nature of the product (e.g., workplace communications) is likely to garner high daily adoption, assuming customers like the product.
With businesses like Slack, it's important to go deeper than simple metrics like DAU to get a true sense of truly engaged users and their growth.
Given Slack's freemium SaaS model, we can look at how many paying customers (e.g., organizations like a company or non-profit) they have and how many major paying customers they have, defined by customers that pay over $100K annually (which is a common SaaS metric).
Below, we've plotted Slack's net dollar retention rate (NDRR) against comps from other leading SaaS companies like Twilio and the newly public, Zoom.
NDRR is a metric that attemps to measure whether a company is successful in increasing the monetary value of a specific cohort of users (often a cohort that signed up in a given year, as we show below).
The simple way to read NDRR is that if the number is above 100%, then the company makes more money off the users from that cohort in the current period than they did in the prior period. If NDRR is below 100%, than the opposite is true. For a detailed walk through of the calculation, see below.
Real interview questions. Sample answers from PM leaders at Google, Amazon and Facebook. Plus study sheets on key concepts.