# What does Fern use? Fern (buildwithfern.com) shows public evidence of 30 tools, according to runsonwhat (last checked 2026-11-13). - Industry: Engineering, Product and Design - Size: 11–50 employees - Based in: New York, United States - Founded: 2022 - LinkedIn: https://www.linkedin.com/company/buildwithfern ## Edge & Hosting | Tool | Category | Evidence | Since | |---|---|---|---| | [Cloudflare](https://www.runsonwhat.com/reverse/cloudflare) | CDN & Edge | DNS records, Website code | | | [Amazon Web Services](https://www.runsonwhat.com/reverse/aws) | Hosting & Cloud | Custom domain, Website code | | | [Amazon CloudFront](https://www.runsonwhat.com/reverse/cloudfront) | CDN & Edge | Custom domain, Website code | 2023-03 | | [Vercel](https://www.runsonwhat.com/reverse/vercel) | Hosting & Cloud | DNS records, Custom domain, DNS verification records, Website code | | ## Application | Tool | Category | Evidence | Since | |---|---|---|---| | [React](https://www.runsonwhat.com/reverse/react) | Frontend | Website code | | | [Tailwind CSS](https://www.runsonwhat.com/reverse/tailwind) | Frontend | Website code | | | [Next.js](https://www.runsonwhat.com/reverse/nextjs) | Frontend | Website code | | | [Stripe](https://www.runsonwhat.com/reverse/stripe) | Payments & Billing | DNS verification records, Website code | | | [Algolia](https://www.runsonwhat.com/reverse/algolia) | Search | Website code | | | [Auth0](https://www.runsonwhat.com/reverse/auth0) | Auth & Identity | Custom domain | 2025-07 | | [WorkOS](https://www.runsonwhat.com/reverse/workos) | Auth & Identity | Custom domain | 2024-03 | ## Data & Observability | Tool | Category | Evidence | Since | |---|---|---|---| | [Google Analytics](https://www.runsonwhat.com/reverse/ga) | Analytics | Website code | | | [Google Tag Manager](https://www.runsonwhat.com/reverse/gtm) | Analytics | Website code | | | [web-vitals](https://www.runsonwhat.com/reverse/web-vitals) | Monitoring | Website code | | | [PostHog](https://www.runsonwhat.com/reverse/posthog) | Analytics | Website code | | | [incident.io](https://www.runsonwhat.com/reverse/incidentio) | Monitoring | Custom domain | 2024-04 | ## Go-to-market | Tool | Category | Evidence | Since | |---|---|---|---| | [Google Ads](https://www.runsonwhat.com/reverse/google-ads) | Ads & Pixels | Website code | | | [LinkedIn Insight Tag](https://www.runsonwhat.com/reverse/linkedin-insight) | Ads & Pixels | Website code | | | [Microsoft Ads](https://www.runsonwhat.com/reverse/bing-ads) | Ads & Pixels | Website code | | | [Webflow](https://www.runsonwhat.com/reverse/webflow) | Website & CMS | Custom domain | 2023-02 | | [Apollo.io](https://www.runsonwhat.com/reverse/apollo) | Sales & CRM | Custom domain | 2024-12 | | [Marketo](https://www.runsonwhat.com/reverse/marketo) | Marketing | Custom domain, Email records | 2026-09 | | [Qualified](https://www.runsonwhat.com/reverse/qualified) | Sales & CRM | Website code | | | [Mintlify](https://www.runsonwhat.com/reverse/mintlify) | Support & Docs | Website code | | | [Pylon](https://www.runsonwhat.com/reverse/pylon) | Support & Docs | DNS verification records | | ## Company Ops | Tool | Category | Evidence | Since | |---|---|---|---| | [Google Workspace](https://www.runsonwhat.com/reverse/google-workspace) | Workspace | Email records, Website code | | | [Valimail](https://www.runsonwhat.com/reverse/valimail) | Security & Compliance | Email records | | | [Tailscale](https://www.runsonwhat.com/reverse/tailscale) | Security & Compliance | DNS verification records | | ## Recent changes at Fern - 2026-11-13: started using [Google Search Console](https://www.runsonwhat.com/reverse/gsc) - 2026-11-13: stopped using [Amazon Route 53](https://www.runsonwhat.com/reverse/route53) - 2026-11-06: started using [Valimail](https://www.runsonwhat.com/reverse/valimail) ## FAQ ### What tools does Fern use? As of November 2026, runsonwhat has found 30 tools at Fern (buildwithfern.com) in public records. Edge & Hosting: Cloudflare, Amazon Web Services and Amazon CloudFront. Application: React, Tailwind CSS and Next.js. Data & Observability: Google Analytics, Google Tag Manager and web-vitals. Go-to-market: Google Ads, LinkedIn Insight Tag and Microsoft Ads. Company Ops: Google Workspace, Valimail and Tailscale. Last checked November 13, 2026. ### What cloud does Fern run on? Fern uses Amazon Web Services for hosting and cloud infrastructure, alongside Vercel, according to runsonwhat (November 2026). runsonwhat found Amazon Web Services through a subdomain that points at Amazon Web Services and code on buildwithfern.com. Amazon Web Services is used by 147,636 companies runsonwhat tracks. ### What sales tools does Fern use? The sales tools runsonwhat has found at Fern are Apollo.io and Qualified (November 2026); no CRM shows up in Fern's public records. runsonwhat found Apollo.io through a subdomain that points at Apollo.io, in use since at least December 2024. ### What email provider does Fern use? Fern uses Google Workspace for email and office software, according to runsonwhat (November 2026). runsonwhat found Google Workspace through email records that authorize Google Workspace and code on buildwithfern.com. Google Workspace is used by 421,815 companies runsonwhat tracks. ### What does Fern use for customer support? Fern uses Mintlify for customer support and documentation, alongside Pylon, according to runsonwhat (November 2026). runsonwhat found Mintlify through Mintlify code on buildwithfern.com. Mintlify is used by 1,251 companies runsonwhat tracks. ### What payment provider does Fern use? Fern uses Stripe for payments and billing, according to runsonwhat (November 2026). runsonwhat found Stripe through a DNS verification record for Stripe and code on buildwithfern.com. Stripe is used by 31,482 companies runsonwhat tracks. ### How long has Fern used Webflow? Fern has used Webflow since at least February 2023, going by the first public certificate of the buildwithfern.com subdomain that points at Webflow. Other long-running tools at Fern include Amazon CloudFront (since March 2023), WorkOS (since March 2024) and incident.io (since April 2024). ### Does Fern use Cloudflare? Yes. runsonwhat found Cloudflare at Fern through DNS records that point at Cloudflare and code on buildwithfern.com. Cloudflare is a CDN & Edge tool used by 735,319 companies runsonwhat tracks. ### Has Fern changed tools recently? Yes. On runsonwhat's rechecks, Fern started using Google Search Console and Valimail (latest on November 13, 2026) and stopped using Amazon Route 53 (latest on November 13, 2026). A change counts only between two checks of buildwithfern.com done the same way. ### Which companies have a tech stack similar to Fern's? The companies with the stacks most like Fern's are Weave, Gigs, Brale and HelixDB, according to runsonwhat (November 2026). Each shares 11 to 16 tools with Fern, and rare tools count for more than common ones like Google Workspace, so the match reflects real stack choices. ### How does runsonwhat know what Fern uses? runsonwhat reads public records only. Of the 30 tools at Fern, 13 were found through code on buildwithfern.com, 8 through subdomains that point at the vendor, 6 through DNS records, 2 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 buildwithfern.com about monthly. --- Source: runsonwhat, https://www.runsonwhat.com/company/buildwithfern.com (updated November 2026). Counts are companies with direct public evidence of the tool (DNS records, certificates, website code, a real-browser crawl, subprocessor lists), so they are lower bounds. Methodology: https://www.runsonwhat.com/methodology.