runsonwhat

Letter's tech stack

What does Letter use?

Letter (letter.dev) uses at least 10 tools we can see from public records, including Vercel for hosting, Google Workspace for email and documents, Cal.com for sales and AthenaHQ for marketing. Last checked .

“A platform for engineers and marketers to extensibly scale GEO, SEO, outbound, and customer success.”

Re-check liveVisit letter.dev
Tools found
10
Categories
7
Layers
4 of 5
Last checked
Oct 2026

Letter's stack, layer by layer

Each tool links to the other companies we've found using it. The label says what kind of public trace gave it away.

Edge & Hosting

1 tool, where the bytes are served from

Hosting & Cloud

Application

2 tools, what the product is built with

Frontend

AI

Go-to-market

3 tools, how they find and keep customers

Marketing

Sales & CRM

Company Ops

4 tools, what the team runs on day to day

Workspace

Security & Compliance

Companies like Letter also use

Tools common among companies with a similar stack that we haven't found at Letter.

Companies with a stack like Letter's

Ranked by shared tools, with rare tools counting more.

Letter tech stack FAQ

What tools does Letter use?

As of November 2026, runsonwhat has found 10 tools at Letter (letter.dev) in public records. Edge & Hosting: Vercel. Application: Next.js. Go-to-market: Cal.com and AthenaHQ. Company Ops: Google Workspace, Let's Encrypt and Sectigo. Last checked October 31, 2026.

What cloud does Letter run on?

Letter uses Vercel for hosting and cloud infrastructure, according to runsonwhat (November 2026). runsonwhat found Vercel through DNS records that point at Vercel. Vercel is used by 50,784 companies runsonwhat tracks.

What sales tools does Letter use?

The sales tools runsonwhat has found at Letter are Cal.com (November 2026); no CRM shows up in Letter's public records. runsonwhat found Cal.com through Cal.com code on letter.dev. Cal.com is used by 928 companies runsonwhat tracks.

What email provider does Letter use?

Letter uses Google Workspace for email and office software, according to runsonwhat (November 2026). runsonwhat found Google Workspace through email records that authorize Google Workspace. Google Workspace is used by 410,457 companies runsonwhat tracks.

What marketing software does Letter use?

Letter uses AthenaHQ for marketing, according to runsonwhat (November 2026). runsonwhat found AthenaHQ through AthenaHQ code on letter.dev. AthenaHQ is used by 41 companies runsonwhat tracks.

Does Letter use Next.js?

Yes. runsonwhat found Next.js at Letter through Next.js code on letter.dev. Next.js is a Frontend tool used by 68,897 companies runsonwhat tracks.

Which companies have a tech stack similar to Letter's?

The companies with the stacks most like Letter's are Authologic, Coris, Dolby and Pago International, according to runsonwhat (November 2026). Each shares 2 to 9 tools with Letter, and rare tools count for more than common ones like Google Workspace, so the match reflects real stack choices.

How does runsonwhat know what Letter uses?

runsonwhat reads public records only. Of the 10 tools at Letter, 5 were found through DNS records, 3 through code on letter.dev, 1 through email records and 1 through website configuration files. A tool is listed only when a direct record backs it up; DNS is rechecked weekly and letter.dev about monthly.

We read public traces only: DNS and email records, certificate logs, website code and published subprocessor lists. A tool is listed when a direct record backs it up, and dropped when a recheck no longer finds it. Is this your company? See how to opt out.