I made Claude read 16K emails to my support inbox. After 15 years, I finally understand who uses my app.

Illustration of a robot at a desk reading a stack of letters by lamplight

I'm the dev of PhoneLeash, an app that forwards texts to email, or to another phone. PhoneLeash was first launched 15 years ago for Android, and in 2026 for iPhone. All this while, the support mailbox has been quietly piling up signal: users writing in with problems, asking for features, describing their setups. Real customer voice — and a lot of it.

For years I'd thought about going through the PhoneLeash support inbox and figuring out who actually uses the app — and for what. I had tried surveys and email nudges but everyone's just too busy.

And I was too busy to read thousands of emails, or write scripts to do the job. There was real work at hand, always. So it was left to the anecdotes I picked up, and a shallow awareness.

Then last week I pointed Claude at my inbox. About an hour later I had deeper insights than ever before. Another half hour and I had this blog post.

If you're interested to know what I found, read on. But if you want to leave now and go do this for your own product, I understand!

Most users are individuals (vs businesses). The rest are interesting.

Donut chart: 12% professionals vs 88% individuals

Across all users, about 88% were individuals — Gmail, Yahoo, iCloud, no signature, no job title, just a name. They're folks with a second phone they don't always carry, users who'd rather see texts on a laptop than a screen, international travelers leaving their home phone behind, families sharing OTPs.

The other 12% are clearly professionals, identifiable by a work email or a signature. That's where the picture gets unexpected.

The professional users aren't who I expected

Illustration of a plumber, real estate agent, office worker, businessman and doctor each looking at their phone

Treemap: top professional sectors

When I built PhoneLeash I had a vague mental model: real-estate agents, plumbers, locksmiths. App users who conduct business over texts, while on the move.

But the data put finance professionals on top — mortgage brokers, insurance agents, CPAs. Surprisingly, their work is wall-to-wall SMS: 2FA codes, client confirmations, signature requests.

Behind them: nonprofits (office managers needing the org line to ring everywhere), tech / on-call IT (sysadmins forwarding the pager to email), and — genuinely surprising — government workers. State Departments, county clerks, Secretary of State offices. Likely users issued a work phone they don't want to carry, who use PhoneLeash so they don't miss anything critical sent to it.

Real estate, healthcare, legal, education, retail — all visible too, but smaller than I'd guessed.

Work email vs personal — and the trades surprise

Pie chart: work email vs personal email

A quarter of all users forwarding to email send their texts to a work or custom-domain address. The rest send to a personal account. The split tracks profession in surprising ways:

Sectors that overwhelmingly use work email (>75%): Government, Legal, Education, Nonprofit. Domains issued by employers, addresses they're allowed to use at work, where personal phones are probably not allowed.
Sectors that overwhelmingly use personal email (>75%): Plumbing and other building trades, Retail, Healthcare.

Illustration of a plumber in a kitchen checking email notifications on his phone

Half forward to email, half forward to a phone

Pie chart: 51% forward to email, 49% forward to a phone

PhoneLeash started life as the "SMS to email" app. Along the way someone wanted to forward to another phone instead, so I built that feature. Now roughly half of my users forward to another phone. These are users forwarding to a backup device, a partner's phone, a work phone etc. The two halves want different things. Email forwarders need readable formatting and search. Phone forwarders need compact messages and reliable reply-back.

I've always treated the phone destination as a first-class use case, even though it's more complex to support and add features to. Seeing the data was great validation.

Inside the email half: Gmail eats everything

Pie chart: Gmail dominates email destinations

When PhoneLeash users do forward to email, almost seven in ten use Gmail. Outlook and Yahoo combined are under 6%. iCloud is statistical noise.

Two things this changes for me:

Email formatting and rendering tests need to focus on Gmail and on the long tail of custom work domains. Outlook / Yahoo are real but not a priority.
A non-trivial one in four PhoneLeash users forwards to a custom or work domain, not a consumer mailbox. That's the hidden professional segment showing up again — bigger here than the 12% support-inbox number because professionals who don't need to email support also don't appear in that 12%.

What I'm doing differently now

As an indie developer, there was just never enough bandwidth to be "metrics-driven". You built a feature, hoped it stuck, and moved on. But with Claude by my side, I can see the results within days, understand them, and fine-tune to hit customer needs squarely.

And one more thing

An Android phone and an iPhone side by side, with messages flowing between them

The most consistent ask in 16,699 emails — "is there an iPhone version?" — finally has a yes. It's live as of this week. If you're one of the many users who wrote in over the years asking for it: thanks for waiting. If you're not, but you want it now: it's on the App Store.

— PL Dev