How a Series A notes app grew two-person workspaces from 19% to 37%

Workspaces inviting a second member up from 19% to 37%: in sprint weeks 9–12, a second person joined 3,645 of 9,850 new workspaces within 14 days, against 19% in April–May. The decision that drove it was to stop asking people to "invite your team" and put the invite where work already gets shared, starting with a one-click "send to attendees" on the AI meeting summary, worth 8.5 points on its own.

Written by Emma Park

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The company and program


Client	A Series A notes app with AI meeting summaries.
Stage	Series A
Industry	Productivity apps
Timeline	One 90-day growth sprint, June 22 – September 20, 2026. Upgrade windows read through October 13
Channels	Web and desktop app, in-app prompts, invite and summary emails
Team	A dedicated Kiko growth lead plus agents for event audits, funnel pulls, experiment write-ups and first drafts of invite copy. Client side: two product engineers and a designer

The approach

A workspace counts when a second person accepts an invite and joins within 14 days of the workspace being created. Every test ran as a 50/50 split on new workspaces.

Test	Hypothesis	Comparison	Decision rule
Send summary to attendees	People invite colleagues when they have something worth sending, not when an onboarding screen asks	After an AI meeting summary, a one-click "send to attendees" from the calendar invite, vs. no prompt	Ship if second member within 14 days rises at least 2 points at 95% confidence, with first-note rate and creator day-30 retention flat or up
Guest comment, one-click join	Recipients join more often if they can read and comment before making an account	Shared notes open for guest comments with a one-click join, vs. a sign-up wall	Same rule
Second seat free for 30 days	The upgrade prompt on the first invite stops people from inviting	Second seat free for 30 days, vs. an upgrade prompt on invite	Same rule, plus Team plan upgrades within 30 days must not fall
Same-domain discovery	Colleagues on the same company domain will join a workspace they can find	New sign-ups see their company's existing workspace, vs. a fresh empty one	Same rule

What we changed

Weeks 1–2: audit and baseline. Fixed the invite events, defined the metric and pulled the April–May funnel: 34% of workspaces sent an invite, 19% got a second member.
Weeks 3–4: send summary to attendees. The biggest single lift, +8.5 points. Shipped to all workspaces in week 5.
Weeks 5–6: guest comments with one-click join. +4.2 points. The "invite step before first note" test ran alongside in week 5 and was reverted.
Weeks 6–7: second seat free for 30 days. +3.7 points, with more Team upgrades, not fewer.
Weeks 7–8: same-domain discovery. +2.1 points. The "AI credits for each invite" test ran in week 8 and was reverted.
Weeks 9–12: hold and measure. No new changes. 14-day invites and 30-day upgrades read for each weekly cohort, then the sprint review.

The results

Before: 18,400 workspaces created in April–May 2026. After: 9,850 workspaces created in sprint weeks 9–12 (August 17 – September 13).

Metric	Before	After	Change
Workspaces with a second member within 14 days	19%	37%	+18 pts
Workspaces sending at least one invite within 14 days	34%	58%	+24 pts
Invites sent per new workspace	0.6	1.4	+0.8 (2.3x)
First note within 24 hours	71%	73%	+2 pts
Team plan upgrade within 30 days	3.1%	5.6%	+2.5 pts
Day-30 retention of the workspace creator	41%	44%	+3 pts

Cohort comparison in PostHog’s dashboard layout, using the same before and after periods as the results table. Recreated from the case-study results; account details omitted. View full report

What didn't work

An "invite teammates" step before the first note. Invites barely moved (31.2% to 31.9%), and first notes within 24 hours fell 9 points. Reverted after one week.
AI credits for each invite. Invites went up, joins didn't, and spam reports tripled. Reverted.
Same-domain discovery on personal email. About 40% of new workspaces sign up with a personal email domain, and discovery does nothing for them.

What we learned

Attach the invite to something the user already wants to send. The meeting summary did more than every other change.
Let recipients see the work before they make an account.
Remove the price from the moment of inviting. Charging at the second seat cost more in invites than it earned in upgrades.

Frequently asked questions

What does a 90-day product growth sprint on team expansion cost?

Kiko's 90-day sprints start at $10,000 a month, and this one used no media. The client supplied two product engineers and a designer to build the four changes. The return showed in Team upgrades within 30 days, up from 3.1% to 5.6%.

How fast did the invite rate move?

The first test, "send summary to attendees", ran in weeks 3–4 and added 8.5 points. All four winners were live by week 8, and weeks 9–12 read 37% with no new changes.

Would this work for a seed-stage notes app with no team plan?

Partly. Sending the summary and guest comments work for any shared document. The second-seat test needs a per-seat price to remove, and same-domain discovery did nothing for the 40% of sign-ups on personal email.

Same industry, other angles:

Creator marketing: 9,400 trial starts in 8 weeks; 27% converted to paid
Paid ads: Paid subscriptions up 3.2x in 4 months at a flat $52 CAC
Full growth system: grew paid seats from 9,000 to 34,000 in 8 months

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