Feyn's tech stack
What does Feyn use?
Feyn (usefeyn.com) uses at least 7 tools we can see from public records, including Fly.io for hosting, Google Workspace for email and documents, Cloudflare for content delivery and Resend for email delivery. Last checked .
“Custom models trained on your data”
- Industry
- Engineering, Product and Design
- Size
- 1–10 employees
- Based in
- San Francisco, United States
- Company page
- Tools found
- 7
- Categories
- 7
- Layers
- 4 of 5
- Last checked
- Oct 2026
Feyn'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
2 tools, where the bytes are served from
Hosting & Cloud
CDN & Edge
Application
2 tools, what the product is built with
Frontend
Media & UI
Go-to-market
1 tool, how they find and keep customers
Marketing
Company Ops
2 tools, what the team runs on day to day
Email Delivery
Workspace
Companies like Feyn also use
Tools common among companies with a similar stack that we haven't found at Feyn.
Companies with a stack like Feyn's
Ranked by shared tools, with rare tools counting more.
GroundControlAviation and Space · 1–10 people2in common
ZazosB2B · 1–10 people4in common
PinchProductivity · 1–10 people4in common
Diffusion StudioContent · 1–10 people4in common
Panta Insurance ServicesInsurance · 1–10 people7in common
Github Downfallgithubdownfall.com2in common
twocaltwocal.app5in common
ImbueResearch · 11–50 people4in common
More Engineering, Product and Design companies
Other Engineering, Product and Design companies we've checked.
21stEngineering, Product and Design · 1–10 people
MidplaneEngineering, Product and Design · 1–10 people
DepotEngineering, Product and Design · 11–50 people
stagewiseEngineering, Product and Design · 1–10 people
ReadMeEngineering, Product and Design · 51–200 people
CorsairEngineering, Product and Design · 1–10 people
Feyn tech stack FAQ
What tools does Feyn use?
We've found 7 tools at Feyn (usefeyn.com). Edge & Hosting: Cloudflare and Fly.io. Application: Google Fonts and Astro. Company Ops: Google Workspace and Resend. Last checked October 2, 2026.
What cloud does Feyn run on?
Feyn uses Fly.io for hosting. We found Fly.io through custom domain.
What email provider does Feyn use?
Feyn uses Google Workspace for email and documents. We found Google Workspace through email records.
Does Feyn use Cloudflare?
Yes. We found Cloudflare at Feyn through DNS records and website code. Cloudflare is used by 147,753 companies we track.
How does runsonwhat know what Feyn uses?
We read public traces only: Feyn's DNS and email records, certificate logs, the code its website loads, and published subprocessor lists. A tool is listed only when a direct record backs it up. DNS is rechecked weekly and the website 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.