Tzvetan Mikov (@tmikov) / X

Tzvetan Mikov

3,737 posts

Tzvetan Mikov

@tmikov

Not my employer's opinions. Meta, Static Hermes - a native AOT JS compiler. Co-founded failed web.archive.org/web/2014011108…

San Francisco Bay Area, USA

Joined October 2010

Pinned
Tzvetan Mikov
@tmikov
Feb 19
Announcing Hermes-node Hermes can now run as a standalone CLI with Node.js-compatible APIs - no C++ embedding required. Technically, hermes-node is a Node.js API compatibility layer for Hermes. It ports Node's native bindings (fs, net, http, child_process, etc.) to Node-API and
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71K
Tzvetan Mikov
@tmikov
Nov 2, 2023
We wanted to show the performance and the insane power of the Static Hermes native FFI. But we don't yet support the all language features needed to compile React Native (soon though!), so we improvised. We imported the bindings for DearImGui (a popular C++ imperative game UI
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Tzvetan Mikov
@tmikov
Nov 5, 2025
Reasonable take on FFmpeg and Google vulnerability controversy: FFmpeg is under no obligation to do anything. If people are unhappy with FFmpeg bugs, they have options: - Don't use FFmpeg - Pay someone to fix it or fix it themselves Nobody is under any obligation to do
55K
Tzvetan Mikov
@tmikov
Oct 19, 2025
Introducing proof of concept React Imgui! The name is a joke, but it is accurate enough. In the last few days I have been working on a prototype of React driving Dear ImGui using Static Hermes. The result is a fully native app written almost entirely in JavaScript, using
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211K
Tzvetan Mikov
@tmikov
Jul 7, 2020
A major milestone: Hermes can now parse the entirety of Facebook's JavaScript codebase, both for web and RN, including all ES6+ features, JSX and Flow type annotations, no Babel or any preprocessing. A single server VM with 24 workers parses 450MB/s. (1 of 3)
Tzvetan Mikov
@tmikov
Apr 9, 2020
For the next Hermes release, we have decreased the installed npm size from 120MB to 18MB!
Split out host tools into separate NPM · facebook/hermes@284ae5e
From github.com
Tzvetan Mikov
@tmikov
Mar 2, 2024
The perf impact of this is curious. Arguments are very cheap in JS, unlike objects. Using the wrong order will kill the hidden class. A lot of optimizations need to happen to eliminate the object allocation and the property access cost. The function better be hot and inlineable.
Cory House
@housecor
Mar 1, 2024
Habit: If a function accepts two arguments of the same type, I accept an object. This protects from accidentally passing args in the wrong order.
170K
Tzvetan Mikov
@tmikov
Sep 22, 2023
Hermes is hiring! We are looking for a C++ engineer in the US, West Coast timezone, to work on the Hermes runtime: standard JS library, runtime internals, garbage collector, etc. No prior experience in language runtimes is needed. Expert level C++ is also not needed, but good
148K
Tzvetan Mikov
@tmikov
Apr 27, 2021
I am proud to announce another major new feature in the next release of Hermes: our new concurrent garbage collector Hades. Up tp 30x shorter GC pause times on 64-bit devices, and up to 14x shorter on 32-bit devices! github.com/facebook/herme…
Tzvetan Mikov
@tmikov
Sep 25, 2024
Meta has rebuilt Instagram and Facebook in React Native for its Quest headsets techcrunch.com/2024/09/25/met… via @techcrunch Can you guess which JS engine is running them? Starts with an "S" and ends with "ermes".
Meta has rebuilt Instagram and Facebook for its Quest headsets | TechCrunch
From techcrunch.com
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Tzvetan Mikov
@tmikov
Sep 9, 2023
This is the slide deck of my Static Hermes announcement at @react_native_eu 2023, #reactnativeeu. Before you view it, please consider these disclaimers: - Static Hermes is WIP, not close to being ready for general use. - The video of the talk is funnier and adds important
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Tzvetan Mikov
@tmikov
Feb 12, 2024
We just landed initial support of generics in Static Hermes, via monomorphization (like Rust/C++). A separate copy of a function or type is generated for each set of distinct type arguments, leading to highly efficient code. Let's dive into how this works in #StaticHermes. 🧵
31K
Tzvetan Mikov
@tmikov
Jul 16, 2025
Hermes v2 ("static_h" branch) performance at end of June 2025, relative to Hermes and QuickJS. Numbers are relative to QuickJS (1.2 means 1.2x faster); higher is better.
29K
Tzvetan Mikov
@tmikov
Nov 2, 2023
Replying to @tmikov
Here is it running on Moto G5.
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