David Justice
@david.justice.dev
Open source at Azure. These are my opinions.
Pinned
David Justice
@david.justice.dev
· Mar 26
Something I can't wait to talk about at #wasmio and @rejekts.io and at #kubecon: how to run #webassembly components at scale but with efficient hardware protection using #hyperlight.
aka.ms/hyperlight-w...
aka.ms/hyperlight-w...
Hyperlight Wasm: Fast, secure, and OS-free - Microsoft Open Source Blog
We're announcing the release of Hyperlight Wasm: a Hyperlight virtual machine “micro-guest” that can run wasm component workloads written in many programming languages. Learn more.
aka.ms
Running #Wasm components inside of a hypervisor and being able to tailor the exact interface between the hosted application and the trusted compute base enables platform builders unequaled ability to tune precisely the access provided to untrusted application code.
Reposted by David Justice
please enjoy: my Wasm-hosted, Wasm-targeting build of Clang/Clang++/LLD: a self-contained, 25 MiB (gzipped) pure function
www.npmjs.com/package/@yow...
www.npmjs.com/package/@yow...
October 26, 2025 at 9:49 AM
please enjoy: my Wasm-hosted, Wasm-targeting build of Clang/Clang++/LLD: a self-contained, 25 MiB (gzipped) pure function
www.npmjs.com/package/@yow...
www.npmjs.com/package/@yow...
Reposted by David Justice
Another depiction if the circularity of capital flows between OpenAI, Microsoft, Nvidia, CoreWeave, AMD, and Oracle.
October 22, 2025 at 11:57 AM
Another depiction if the circularity of capital flows between OpenAI, Microsoft, Nvidia, CoreWeave, AMD, and Oracle.
Reposted by David Justice
For those Master's or Ph.D. students doing systems work, you might have a look at this internship with @microsoft.com's research team: www.linkedin.com/posts/pedroh...
Yes, you'll do some immediately important work, and it's really cool, too.
Yes, you'll do some immediately important work, and it's really cool, too.
🚀 Internship Opportunity in Systems Research
The Microsoft Research - Systems Group https://lnkd.in/dPCb5fqC) and the Azure Research - Systems https://lnkd.in/dhf6Xx-s) are hiring an intern to help… ...
🚀 Internship Opportunity in Systems Research
The Microsoft Research - Systems Group https://lnkd.in/dPCb5fqC) and the Azure Research - Systems https://lnkd.in/dhf6Xx-s) are hiring an intern to help b...
www.linkedin.com
September 30, 2025 at 2:54 PM
For those Master's or Ph.D. students doing systems work, you might have a look at this internship with @microsoft.com's research team: www.linkedin.com/posts/pedroh...
Yes, you'll do some immediately important work, and it's really cool, too.
Yes, you'll do some immediately important work, and it's really cool, too.
Impressive work from Don Syme on Continuous Test Improvement. The post highlights how AI-driven workflows can systematically expand and improve test coverage with minimal cost and time. dsyme.net/2025/08/27/o...
On Continuous Test Improvement
Ever since we started working on “task-oriented programming”, our group at GitHub Next have been throwing around ideas related to “continuous” tasks in software repositories…
dsyme.net
August 27, 2025 at 5:46 PM
Impressive work from Don Syme on Continuous Test Improvement. The post highlights how AI-driven workflows can systematically expand and improve test coverage with minimal cost and time. dsyme.net/2025/08/27/o...
I think agentic coding AI's offer a really interesting test for usability. Say you are building dev tools and you want to see if given documentation a new user could do it, give it to the AI and see where it fails. I'm going to bet the places where the AI fails will be sticking points for humans.
August 8, 2025 at 3:39 PM
I think agentic coding AI's offer a really interesting test for usability. Say you are building dev tools and you want to see if given documentation a new user could do it, give it to the AI and see where it fails. I'm going to bet the places where the AI fails will be sticking points for humans.
Must read post from @rawkode.dev that does a wonderful job explaining the differences between Wassette and common ways of running MCP workloads.
I'm super excited for Wassette, so I put together a quick article on why it's important and a comparison with our current options for MCP.
August 7, 2025 at 2:54 PM
Must read post from @rawkode.dev that does a wonderful job explaining the differences between Wassette and common ways of running MCP workloads.
🎉 Introducing Wassette: a runtime for secure, sandboxed WebAssembly Component tool execution via the Model Context Protocol (MCP). Easily register reusable WASM tools inside AI agents like VS Code all without leaving the chat window. Start using it to safely extend your agent’s capabilities! 🚀
Introducing Wassette: WebAssembly-based tools for AI agents by Yosh Wuyts opensource.microsoft.com/blog/2025/08...
Introducing Wassette: WebAssembly-based tools for AI agents - Microsoft Open Source Blog
Wassette is a secure, open-source Model Context Protocol server that leverages WebAssembly to provide a trusted execution environment for untrusted tools.
opensource.microsoft.com
August 6, 2025 at 3:42 PM
🎉 Introducing Wassette: a runtime for secure, sandboxed WebAssembly Component tool execution via the Model Context Protocol (MCP). Easily register reusable WASM tools inside AI agents like VS Code all without leaving the chat window. Start using it to safely extend your agent’s capabilities! 🚀
Reposted by David Justice
Our USENIX ;login; article on Crescendo just dropped! We discovered what might be the most powerful blackbox jailbreak technique - Crescendo is undefeated against all frontier AI models in every harm domain we tested. I'm presenting at USENIX Security on August 14th.
www.usenix.org/publications...
www.usenix.org/publications...
July 31, 2025 at 10:21 PM
Our USENIX ;login; article on Crescendo just dropped! We discovered what might be the most powerful blackbox jailbreak technique - Crescendo is undefeated against all frontier AI models in every harm domain we tested. I'm presenting at USENIX Security on August 14th.
www.usenix.org/publications...
www.usenix.org/publications...
Reposted by David Justice
i've modified wasi-libc and wasi-sdk (PRs pending) so that you always have the concurrency APIs (pthread_*, thrd_*, <thread>, <mutex>, <atomic>) available to you, even in single-threaded targets. this makes porting applications (especially C++ ones) much, _much_ easier!
Refactor stub pthread library and enable unconditionally by whitequark · Pull Request #602 · WebAssembly/wasi-libc
This PR changes the layout of the stub pthread library to match that of libc-top-half: splits it into (mostly) one file per function, and ensures the same API is exposed from both libraries, adding...
github.com
July 26, 2025 at 5:45 PM
i've modified wasi-libc and wasi-sdk (PRs pending) so that you always have the concurrency APIs (pthread_*, thrd_*, <thread>, <mutex>, <atomic>) available to you, even in single-threaded targets. this makes porting applications (especially C++ ones) much, _much_ easier!
Reposted by David Justice
For those who are about difficult hardware #virtualization efficiency and dev experience (WTF????) you might find @dblnz.dev's blog post on #hyperlight and interactive debugging interesting. It's a blast for any micro-guest, including #webassembly. opensource.microsoft.com/blog/2025/07...
Hyperlight: Debugging hardware-protected guests - Microsoft Open Source Blog
Find out how you can step through code in your guest micro-VM by attaching the GNU Debugger at runtime to debug Hyperlight guest micro-VMs.
opensource.microsoft.com
July 15, 2025 at 4:33 PM
For those who are about difficult hardware #virtualization efficiency and dev experience (WTF????) you might find @dblnz.dev's blog post on #hyperlight and interactive debugging interesting. It's a blast for any micro-guest, including #webassembly. opensource.microsoft.com/blog/2025/07...
Reposted by David Justice
Missed this: very good article by @thenewstack.io on a @rejekts.io talk prior to #kubeconEU about #hyperlight and #webassembly in #envoy. Slow as a first draft; but getting faster and makes hostile multitenant #networkfunctions possible to imagine. thenewstack.io/webassembly-...
WebAssembly, ‘Hyper VMs’ and Hypervisors: Fast Speeds, Intense Isolation
In this article, we look at what happens when you combine WebAssembly with Hyperlight.
thenewstack.io
July 7, 2025 at 7:11 PM
Missed this: very good article by @thenewstack.io on a @rejekts.io talk prior to #kubeconEU about #hyperlight and #webassembly in #envoy. Slow as a first draft; but getting faster and makes hostile multitenant #networkfunctions possible to imagine. thenewstack.io/webassembly-...
Reposted by David Justice
I confess to liking the progress made in the #Dual-LLM family of #llm security patterns started with @simonwillison.net's original Dual-LLM "separation of query concerns" in simonwillison.net/2023/Apr/25/....
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The Dual LLM pattern for building AI assistants that can resist prompt injection
I really want an AI assistant: a Large Language Model powered chatbot that can answer questions and perform actions for me based on access to my private data and tools. …
simonwillison.net
June 26, 2025 at 12:39 PM
I confess to liking the progress made in the #Dual-LLM family of #llm security patterns started with @simonwillison.net's original Dual-LLM "separation of query concerns" in simonwillison.net/2023/Apr/25/....
....
....
Reposted by David Justice
I put LLM spike coding into all my recruitment ads, in white font. Some of the replies are a lot of fun, and it sure speeds up shortlisting.
June 19, 2025 at 11:38 AM
I put LLM spike coding into all my recruitment ads, in white font. Some of the replies are a lot of fun, and it sure speeds up shortlisting.
Come join Taylor Thomas and I today as we discuss Wasm I Right or Wasm I Wrong? a Review of the Wasm Ecosystem at KubeCon + CloudNativeCon Europe 2025 sched.co/1tcxS #KubeCon
KubeCon + CloudNativeCon Europe 2025: Wasm I Right or Wasm I Wrong? a Review o...
View more about this event at KubeCon + CloudNativeCon Europe 2025
sched.co
April 2, 2025 at 7:19 AM
Come join Taylor Thomas and I today as we discuss Wasm I Right or Wasm I Wrong? a Review of the Wasm Ecosystem at KubeCon + CloudNativeCon Europe 2025 sched.co/1tcxS #KubeCon
Come join Terence Lee and I today as we discuss Building WebAssembly Like It's 2011 - at KubeCon + CloudNativeCon Europe 2025 sched.co/1txGl
KubeCon + CloudNativeCon Europe 2025: Building WebAssembly Like It's 2011 - Da...
View more about this event at KubeCon + CloudNativeCon Europe 2025
sched.co
April 2, 2025 at 7:15 AM
Come join Terence Lee and I today as we discuss Building WebAssembly Like It's 2011 - at KubeCon + CloudNativeCon Europe 2025 sched.co/1txGl
Running #Wasm components inside of a hypervisor and being able to tailor the exact interface between the hosted application and the trusted compute base enables platform builders unequaled ability to tune precisely the access provided to untrusted application code.
Something I can't wait to talk about at #wasmio and @rejekts.io and at #kubecon: how to run #webassembly components at scale but with efficient hardware protection using #hyperlight.
aka.ms/hyperlight-w...
aka.ms/hyperlight-w...
Hyperlight Wasm: Fast, secure, and OS-free - Microsoft Open Source Blog
We're announcing the release of Hyperlight Wasm: a Hyperlight virtual machine “micro-guest” that can run wasm component workloads written in many programming languages. Learn more.
aka.ms
March 26, 2025 at 2:19 PM
Running #Wasm components inside of a hypervisor and being able to tailor the exact interface between the hosted application and the trusted compute base enables platform builders unequaled ability to tune precisely the access provided to untrusted application code.
Good day, folks! The #CNCF TAG-Runtime Wasm Working Group is meeting today in about 30 mins. We'll be covering updates on WASI cloud interfaces (blob, key/value, config, etc) and an update on WASI preview 3! Come join or just listen in! docs.google.com/document/d/1...
Wasm-WG Meeting Notes
§WASM WG | Meeting Notes 📆 📅 Fortnightly, Tuesdays at 5:00 pm CET/ 8:00 am PST Tockify Calendar Charter Join the Zoom Meeting Wasm Working Group Slack Past Meetings (TAG-Runtime channel) ...
docs.google.com
March 18, 2025 at 2:29 PM
Good day, folks! The #CNCF TAG-Runtime Wasm Working Group is meeting today in about 30 mins. We'll be covering updates on WASI cloud interfaces (blob, key/value, config, etc) and an update on WASI preview 3! Come join or just listen in! docs.google.com/document/d/1...
Delighted to see this post land! Learn how you can make a guest for Hyperlight to execute code in a secure sandbox with "Build a Hyperlight C guest to securely execute Javascript" opensource.microsoft.com/blog/2025/03...
Build a Hyperlight C guest to securely execute Javascript - Microsoft Open Source Blog
This article will show you how to create a “guest” application that uses the Hyperlight library and have fun with some JavaScript. Learn more.
opensource.microsoft.com
March 10, 2025 at 7:41 PM
Delighted to see this post land! Learn how you can make a guest for Hyperlight to execute code in a secure sandbox with "Build a Hyperlight C guest to securely execute Javascript" opensource.microsoft.com/blog/2025/03...
If you were unable to make it to the Wasm working group with week, here's the recording youtu.be/dGvEMWYvenM?.... It was great to have the @zed.dev folks chat with us about their component model usage, and the JS/TS stack folks to discuss the tools and projects involved. Thank you, presenters!!
March 6, 2025 at 8:27 PM
If you were unable to make it to the Wasm working group with week, here's the recording youtu.be/dGvEMWYvenM?.... It was great to have the @zed.dev folks chat with us about their component model usage, and the JS/TS stack folks to discuss the tools and projects involved. Thank you, presenters!!
Hey Folks, the CNCF Wasm WG will be meeting today to talk about all things #Wasm. Joining us today are folks from @zed.dev to discuss their use of the component model to extend Zed. We'll also be joined by folks discussing their work on JS/TS WASI support. Join us: docs.google.com/document/d/1...
Wasm-WG Meeting Notes
§WASM WG | Meeting Notes 📆 📅 Fortnightly, Tuesdays at 5:00 pm CET/ 8:00 am PST Tockify Calendar Charter Join the Zoom Meeting Wasm Working Group Slack Past Meetings (TAG-Runtime channel) ...
docs.google.com
March 4, 2025 at 3:04 PM
Hey Folks, the CNCF Wasm WG will be meeting today to talk about all things #Wasm. Joining us today are folks from @zed.dev to discuss their use of the component model to extend Zed. We'll also be joined by folks discussing their work on JS/TS WASI support. Join us: docs.google.com/document/d/1...
Reposted by David Justice
Very happy that the @cncf.io toc has voted to accept #hyperlight into the sandbox program! github.com/cncf/sandbox...
[Sandbox] Hyperlight · Issue #312 · cncf/sandbox
Application contact emails [email protected],[email protected],[email protected] Project Summary Hyperlight is an open-source Rust library you can use to execute smal...
github.com
March 1, 2025 at 11:23 AM
Very happy that the @cncf.io toc has voted to accept #hyperlight into the sandbox program! github.com/cncf/sandbox...
Reposted by David Justice
My closing keynote from Rust Nation UK last week is now online: "Microsoft is Getting Rusty: A Review of Successes and Challenges"
Microsoft is Getting Rusty: A Review of Successes and Challenges - Mark Russinovich
YouTube video by Rust Nation UK
www.youtube.com
February 26, 2025 at 10:18 PM
My closing keynote from Rust Nation UK last week is now online: "Microsoft is Getting Rusty: A Review of Successes and Challenges"
Reposted by David Justice
I'm super proud to be, with colleagues in humanity @anfibiacreativa.bsky.social ( @microsoft.com ) and @tschneidereit.bsky.social ( @fermyon.com ) to update our survey of debugging core #webassembly and #wasm components at #wasmio in Barcelona! 2025.wasm.io/sessions/no-...
It can now be done!
It can now be done!
WASM I/O • 27-28 Mar • Barcelona 2025
No More Printf: Interactive Debugging Wasm for web and server • Wasm I/O 2025. A 2-day WebAssembly conference in Barcelona, Spain
2025.wasm.io
February 21, 2025 at 11:05 AM
I'm super proud to be, with colleagues in humanity @anfibiacreativa.bsky.social ( @microsoft.com ) and @tschneidereit.bsky.social ( @fermyon.com ) to update our survey of debugging core #webassembly and #wasm components at #wasmio in Barcelona! 2025.wasm.io/sessions/no-...
It can now be done!
It can now be done!
Reposted by David Justice
Here's @bluestein.bsky.social's uncensored thread of the town hall held by Rep. Rich McCormick (R-GA), in which an unhappy audience pushes back against DOGE cuts: threadreaderapp.com/thread/18927...
Over on X, simple tweets by my colleague Greg Bluestein of the Atlanta Journal Constitution have been blocked. They were nothing but video of a town hall held by Rep. Rich McCormick R-GA where he was asked questions about DOGE
February 21, 2025 at 3:31 AM
Here's @bluestein.bsky.social's uncensored thread of the town hall held by Rep. Rich McCormick (R-GA), in which an unhappy audience pushes back against DOGE cuts: threadreaderapp.com/thread/18927...
Reposted by David Justice
At @rejekts.io there's tons of stuff to see. I'm looking forward to a little hot #envoy #webassembly network filter action with cfp.cloud-native.rejekts.io/cloud-native....
Wasm, Envoy, and Hyperlight Walk Into a Pod: No Vulnerabilities Allowed Cloud Native Rejekts Europe (London) 2025
Hyperlight, which has been submitted to CNCF, adds a new layer of security to WebAssembly workloads. By leveraging hardware-assisted virtualization via KVM or Hyper-V, Hyperlight creates ultra-lightwe...
cfp.cloud-native.rejekts.io
February 20, 2025 at 10:46 AM
At @rejekts.io there's tons of stuff to see. I'm looking forward to a little hot #envoy #webassembly network filter action with cfp.cloud-native.rejekts.io/cloud-native....