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GTM engineering case study: How Understory Agency added an outbound engine to 8 years of product-led growth at Expensify

How Understory Agency took reply rates from 0.14% to 1.5% on one enrichment field, and added an outbound motion to 8 years of PLG at Expensify.
Alex FineAlex FineLinkedIn β†—|August 23, 2026Case study9 min read
Mitch Ward of Expensify on the outbound engine Understory Agency built

A cold email is decided before anyone writes it, by what the sender already knows about the person receiving it. On Expensify's outbound program the clearest evidence of that sits in a single enrichment field. When the prospect's accounting package is known before the email goes out, the reply rate is 1.5%. Where it is unknown, the same program replies at 0.14%.

Expensify sells expense management to finance teams, and it is one of the more complete product-led growth stories in B2B software. Mitch Ward has been there 8 years. For most of that time the company grew on the product itself, which left it with almost no outbound strategy and an entire category of buyer nobody was speaking to. His description of the gap is a dire need to find leads that were not finding Expensify naturally.

Nothing about the engagement was designed to move Expensify off product-led growth. Mitch calls it the tried and tested engine that continues to drive results, and the brief for Understory Agency was to bring outbound and the wider go-to-market motion up to match it. Every reply the outbound program earns is a conversation the product was never going to start on its own.

Understory Agency has run Expensify's GTM engineering since June 2025. The program has sent 125,000 emails, reached 54,000 net-new contacts and produced 180 to 190 positive replies. On the inbound side of the same build, roughly 17,000 unengaged leads were enriched and 30,000+ leads were scored into the CRM for the first time.

Here is how we built it.

Expensify at a glance
IndustryExpense management, NASDAQ: EXFY
HeadquartersPortland, OR
ServicesGTM engineering, run by Understory Agency
EngagementLive June 2025, ongoing. Understory Agency engagements typically run 6 months
Headline resultA 1.5% reply rate where the prospect's accounting package is known, against 0.14% where it is unknown

Performance Summary (from June 2025)

About Expensify

Industry: Expense management

Expensify is an expense management platform for finance teams, publicly traded on NASDAQ under EXFY and headquartered in Portland, Oregon. The company is product-led, and self-serve signup has carried its growth through most of the last 8 years. Understory Agency has run Expensify's GTM engineering since June 2025, covering lead sourcing, campaign build, enrichment, lead scoring and the tooling underneath all of it.

The Challenge

Understory Agency arrived at a company where the product had been doing the selling for 8 years. That is a good problem to inherit and a specific one to solve. A product-led motion reaches the buyers who go looking. It does not reach the ones who never search for the category, or the ones who evaluate software by taking a call. Expensify had no outbound machinery to reach that second group, so the work started from a blank page instead of a rebuild.

The second problem sat inside the inbound flow that product-led growth was already producing. Over 1 million people visit the homepage and roughly 1% of them sign up. Around 70% of leads never engaged sales at all. There was no lead scoring, so nothing in the system separated a finance team that could buy from a single user who never would. Routing ran purely off self-reported employee count, and roughly 30% of signups arrived on personal email addresses, which meant the firmographics behind them were unknown. Nurture was a single static template. In a colleague's words, SMBs all the way up to the enterprise were getting the same type of messaging.

Mitch's first reason for choosing Understory Agency was the tooling depth. He names enrichment, lead sourcing and CRM work in HubSpot, using tools Expensify had not run before. The second reason was how the team operates, which he describes as the balance of an internal employee with a consultative partner who says what the company should be doing.

The numbers before we began

Understory Agency maps what a company already has before building anything. In June 2025, Expensify had:

πŸ‘‰ 8 years of product-led growth with almost no outbound strategy attached to it

πŸ‘‰ Over 1 million homepage visitors with roughly 1% signing up

πŸ‘‰ Around 70% of leads never engaging sales

πŸ‘‰ No lead scoring at all, so no way to tell a high-fit signup from a low-fit one

πŸ‘‰ Routing keyed purely off self-reported employee count

πŸ‘‰ Roughly 30% of signups on personal email addresses, with the firmographics behind them unknown

πŸ‘‰ A single static nurture template serving every segment from SMB to enterprise

The Strategy: Enrich the buyer before anyone writes the email

The finding that shaped the whole program is the one worth taking away from it. Expensify sells into the back office, so the accounting platform a company runs tells you the shape of that back office and gives the email something true and specific to say. Understory Agency measured what happens when that field is known before the send. The reply rate rises from 0.14% to 1.5%, better than tenfold, off 1 enrichment field. Every hour spent enriching a list before outreach is buying that difference, and it is why the build order here put data first and copy second.

That principle got formalised as a lead scoring model, because a signal worth writing an email around is also a signal worth routing on. Understory Agency built Expensify a 100-point model and scored 30,000+ leads into the CRM with it.

The 100-point lead scoring model Understory Agency built for Expensify
Signal groupPoints
Core firmographic40
Back office tech and accounting20, of which the accounting platform alone is worth 15
Product signals30
Person score10

Scores bucket into 4 bands: 80 to 100 Hot, 60 to 79 Warm, 40 to 59 Nurture, and under 40 Low. The accounting platform carries 15 of the 100 points on its own, which is the same finding as the reply-rate gap expressed as a routing rule.

Sending was built on Expensify's own domain, and getting that approved inside a public company is the hard part. Understory Agency got 50 subdomains approved and stood up 141 inboxes across 47 domains, each warmed for 14 days before it carried a campaign. The reason for the approval work is measurable. Expensify's domain was registered in 2007 and carries a domain authority of 19.8, against 1.1 for Understory Agency's own sending domains. Mail sent from a domain with that much history behind it lands differently, and the deliverability of the whole program rests on it.

The most transferable idea in the engagement came from data Expensify already owned. Understory Agency analysed the existing product user base to see who signs up and then converts against who signs up and disappears, isolating the technographic, firmographic and geographic patterns that separate the 2 groups. That analysis did 2 jobs. It sharpened the outbound ICP against evidence from real conversions, and it identified the lapsed free-trial cohort as an audience worth re-engaging directly. For any product-led company sitting on years of signup data, this is the highest-value list in the building and it is already paid for.

One vendor decision is worth publishing because it went the other way. A data provider delivered 40,000 contacts. Those became roughly 1,000 business emails, and roughly 500 of those survived the ICP filter, a yield of 1.25%. Roughly 30% of the same vendor's "high intent" list was already on Expensify's block list. Understory Agency killed the vendor. Data that fails at that rate wastes the spend and degrades the sending reputation the rest of the program depends on. Around those decisions, the operating layer runs continuously:

The Results (from June 2025)

πŸ‘‰ Reply rate of 1.5% where the prospect's accounting package is known, against 0.14% where it is unknown

πŸ‘‰ 125,000 emails sent cumulatively across the program

πŸ‘‰ 54,000 net-new contacts reached, an audience Expensify's product-led motion was not reaching

πŸ‘‰ 180 to 190 positive replies cumulatively

πŸ‘‰ Roughly 17,000 unengaged inbound leads enriched

πŸ‘‰ 30,000+ leads scored into the CRM on the 100-point model

πŸ‘‰ 100,000+ rows enriched in Clay and pushed back into Expensify's systems

πŸ‘‰ Clay refresh rate from 24 hours to 15 minutes, via custom automation

πŸ‘‰ Roughly 6% reply rate and 21 positive replies from the SMB finance and accounting segment, Gmail-only, 1 to 100 employees, on a roughly 10,000-person list

πŸ‘‰ 5% reply rate and 22% open rate on conference-related campaigns

πŸ‘‰ 50 approved subdomains and 141 inboxes across 47 domains, sending on a domain registered in 2007 at a domain authority of 19.8

Key Takeaways

What Expensify says

What Expensify says about Understory Agency

β€œWe've seen material revenue being generated from leads that have been 100% attributable to our outbound efforts with you all. So on both fronts, whether inbound or purely outbound, we've seen revenue that we would not have gotten otherwise, to put it in its simplest terms.”

Mitch WardExpensify

β€œThat nice balance of a feel of taking on essentially an internal employee. Super responsive, all online all the time, available to answer questions with zero ramp-up speed.”

Mitch WardExpensify

Conclusion

Expensify came to Understory Agency with 8 years of product-led growth and no machinery for reaching the buyers the product never met. Since June 2025 the program has sent 125,000 emails to 54,000 net-new contacts and returned 180 to 190 positive replies, on infrastructure of 141 inboxes across 47 domains approved on Expensify's own domain. Inbound got the same treatment, with roughly 17,000 unengaged leads enriched and 30,000+ scored into the CRM. Product-led growth keeps running as the engine it has always been, with outbound coming up alongside it.

The same shape shows up at every company that grew on self-serve. The signup flow works, the pipeline is real, and the buyers who never search for the category stay invisible. Understory Agency builds and runs the motion that reaches them.

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Understory Agency runs paid media, GTM engineering, LinkedIn content, creative and RevOps as one team, for 100+ B2B companies from seed to IPO. Clients include Clay, Zapier, Expensify, RemoFirst and RB2B.

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FAQ

Does enriching a list before outreach actually improve cold email reply rates?

Yes, and the size of the effect surprises most teams. What moves the number is a single field that tells you something real about how the prospect operates, which gives the email a specific reason to exist. Knowing a company's headcount changes little. Knowing which system their finance team runs changes the message. On the program Understory Agency runs for Expensify, the reply rate is 1.5% where the prospect's accounting package is known and 0.14% where it is unknown.

How does a product-led growth company add outbound without undercutting the product-led motion?

Treat them as separate audiences. Product-led growth captures buyers who are already looking, and outbound reaches the category of buyer who never searches, plus the signups who arrived and then went quiet. The 2 motions share a data layer, so scoring, routing and enrichment serve both. At Expensify, product-led growth remains the engine and Understory Agency built outbound alongside it.

Should cold email be sent from your own domain or from separate sending domains?

Subdomains of a domain you already own are the stronger option where the company will approve them. They inherit the age and authority of the parent domain, and a newly registered sending domain has neither. The trade is internal: it takes security and IT approval, and every inbox still needs a warm-up period before it carries volume. Understory Agency got 50 subdomains approved for Expensify and built 141 inboxes across 47 domains, each warmed for 14 days, on a domain registered in 2007.

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