# Bert Belder

> Bert Belder is deno co-founder and CTO; now Cloudflare workerd self-hosting lead. Deno Sandbox on Anchor Terminal, with grades, an about and public profiles.

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- Updated: 2026-10-28

Deno co-founder and CTO; now Cloudflare workerd self-hosting lead.

Bert Belder co-created the Deno JavaScript and TypeScript runtime with Ryan Dahl at Deno Land. After the Deno team joined Cloudflare in October 2026, he and Dahl lead an effort to make self-hosting Cloudflare's workerd runtime a supported way to build and run apps on the Workers programming model.

- LinkedIn: https://www.linkedin.com/in/bertbelder

## What Bert builds

- [Deno Sandbox](https://www.anchorterminal.com/tools/deno-sandbox.md), graded D, 50.4/100, in Code execution sandboxes. Deno Sandbox runs Linux microVMs on Deno Deploy for untrusted or AI-generated code. It is driven from the `@deno/sandbox` JavaScript SDK, the `deno-sandbox` Python SDK or the `deno sandbox` CLI, and launched in beta on 3 February 2026. Deno co-founder and CTO; now Cloudflare workerd self-hosting lead, researched 2026-10-27.

## Works with

- [Ryan Dahl](https://www.anchorterminal.com/people/ryan-dahl/), Deno co-founder; Sandbox launch author; now Cloudflare workerd self-hosting lead

## Backed by

- [Four Rivers](https://www.anchorterminal.com/investors/four-rivers/)
- [Rauch Capital](https://www.anchorterminal.com/investors/rauch-capital/)
- [Long Journey Ventures](https://www.anchorterminal.com/investors/long-journey-ventures/)
- [Mozilla](https://www.anchorterminal.com/investors/mozilla/)
- [Shasta Ventures](https://www.anchorterminal.com/investors/shasta-ventures/)
- [Ben Noordhuis](https://www.anchorterminal.com/investors/ben-noordhuis/)
- [Sequoia Capital](https://www.anchorterminal.com/investors/sequoia-capital/)
- [Insight Partners](https://www.anchorterminal.com/investors/insight-partners/)
- [Automattic](https://www.anchorterminal.com/investors/automattic/)
- [Netlify](https://www.anchorterminal.com/investors/netlify/)
- [Nat Friedman](https://www.anchorterminal.com/investors/nat-friedman/)
- [Dylan Field](https://www.anchorterminal.com/investors/dylan-field/)

## Questions

### Who is Bert Belder?

Bert Belder co-created the Deno JavaScript and TypeScript runtime with Ryan Dahl at Deno Land. After the Deno team joined Cloudflare in October 2026, he and Dahl lead an effort to make self-hosting Cloudflare's workerd runtime a supported way to build and run apps on the Workers programming model.

### What does Deno Land Inc. make?

Anchor Terminal lists Deno Sandbox from Deno Land Inc.. Deno Sandbox runs Linux microVMs on Deno Deploy for untrusted or AI-generated code. It is driven from the @deno/sandbox JavaScript SDK, the deno-sandbox Python SDK or the deno sandbox CLI, and launched in beta on 3 February 2026.

### Who has invested in Deno Land Inc.?

The sources our research read name Four Rivers, Rauch Capital, Long Journey Ventures, Mozilla, Shasta Ventures, Ben Noordhuis, Sequoia Capital, Insight Partners, Automattic, Netlify, Nat Friedman and Dylan Field.

### How are Bert's tools graded?

Deno Sandbox is graded D, 50.4 out of 100, on Anchor Terminal's benchmark, which scores every listing against the same checklist.

## Sources

- https://deno.com/blog/introducing-deno-sandbox
- https://deno.com/blog/cloudflare
- https://blog.cloudflare.com/deno-joins-cloudflare/
- https://x.com/rough__sea
- https://www.linkedin.com/in/bertbelder
- https://deno.com/
- https://deno.com
- https://www.linkedin.com/company/deno
- https://docs.deno.com/sandbox/

These are the people building the tools we list, named for their public role in the company or project behind a listing, from public pages, with the date it was researched. They don't work for Anchor Terminal (our own team is on the about page, /about/#author). We show public roles, public profiles and what the listing pages show, nothing private. To correct something, send an about or a photo, or have a page removed, write to privacy@anchorterminal.com.

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