{"slug": "libriscv", "name": "libriscv", "category": "dev-libs", "category_name": "Libraries and frameworks", "description": "", "recommenders": 3, "commenters": 3, "warners": 0, "score": 2.684, "rising": -0.98, "first": "2025-12-23", "latest": "2026-07-21", "why": "this has the least latency out of any sandbox at only minor consequence of performance that they know of", "why_is_quote": true, "has_verdict": false, "sentiment": {"recommend": 5, "neutral": 0, "compare": 0, "warn": 0}, "spark": [0, 1, 1, 1, 0, 0, 1, 0, 1, 0, 0, 0], "listed": true, "loved": [], "caveat": "", "short_quote": "this has the least latency out of any sandbox at only minor consequence of performance that they know of", "kind": "", "icon": true, "domain": null, "github_repo": "github.com/libriscv/libriscv", "official_url": "https://github.com/libriscv/libriscv", "pricing": "", "aliases": ["libriscv"], "verdict": null, "praise": [{"label": "", "summary": "", "quotes": [{"id": 783844800, "item_id": 48990300, "url": "https://news.ycombinator.com/item?id=48990300", "by": "sph", "date": "2026-07-21", "stance": "recommend", "quote": "A very fast RISC-V VM with sandboxing of memory and syscalls.", "excerpt": "If you don't want to delegate the fun of learning to an LLM, here's how I've built a RV64IM simulator in C in a weekend. All you need is an opcode table, the RISC-V specs and to implement each instruction; the good thing of RISC CPUs is that instructions are very simple (i.e. pretty much everything is a variation of `dest = src1 OP src2`) and memory instructions are dedicated. The other cool thing is that there are n", "context": "", "use_case": "", "switched_from": "", "story": "Running Doom on Our Custom CPU and Going Viral"}, {"id": 769260960, "item_id": 48078810, "url": "https://news.ycombinator.com/item?id=48078810", "by": "Imustaskforhelp", "date": "2026-05-09", "stance": "recommend", "quote": "libriscv is one of the fastest libriscv emulators", "excerpt": "I have only read the first end of the article but I can't help but think that a project like libriscv[0] would've/could've worked for their game project too because fun fact but the creator of librsicv, the legendary fwsgonzo is also making a game. I highly recommend for people to check out their discord server. But my main point is that libriscv is one of the fastest libriscv emulators and then something like C/C++/", "context": "", "use_case": "sandboxed game scripting", "switched_from": "", "story": "Making your own programming language is easier than you think (but also harder)"}, {"id": 753174496, "item_id": 47073406, "url": "https://news.ycombinator.com/item?id=47073406", "by": "networked", "date": "2026-02-19", "stance": "recommend", "quote": "The author may like", "excerpt": "This is fun. The author may like https://skarnet.org/software/execline/ (can be containerized the same way?), https://github.com/darius/awklisp, and https://github.com/libriscv/libriscv + https://github.com/libriscv/libloong.", "context": "", "use_case": "", "switched_from": "", "story": "Show HN: A Lisp where each function call runs a Docker container"}, {"id": 745326945, "item_id": 46582934, "url": "https://news.ycombinator.com/item?id=46582934", "by": "Imustaskforhelp", "date": "2026-01-11", "stance": "recommend", "quote": "which is a sandbox (The fastest RISC-V sandbox)", "excerpt": "I recently had a question about what AI sandboxes use and I think Modal uses gvisor under the hood and I think others use firecracker/generally favour it as well Firecracker kind of ends up being in the VM categories and I would place gvisor in a similar category too under the VM So in my opinion, VM's are sandboxes. Of course there is also libriscv https://github.com/libriscv/libriscv which is a sandbox (The fastest", "context": "", "use_case": "", "switched_from": "", "story": "FUSE is All You Need \u2013 Giving agents access to anything via filesystems"}, {"id": 742644672, "item_id": 46415292, "url": "https://news.ycombinator.com/item?id=46415292", "by": "Imustaskforhelp", "date": "2025-12-28", "stance": "recommend", "quote": "I really appreciate libriscv", "excerpt": "Fwsgonzo, what a legend man!! I am not kidding but before seeing this post, I had commented about my experiences in the libriscv discord server (I am the person who had created the AUR arch repository for simplekvm but had to pull them down) For reference: https://news.ycombinator.com/item?id=46413053#46415223 Call this luck or whatever, but I really appreciate libriscv and I will definitely try to be more active, A ", "context": "", "use_case": "RISC-V emulation", "switched_from": "", "story": "Show HN: LoongArch Userspace Emulator"}]}], "caveats": [], "who": [], "tags": [], "use_cases": ["sandboxed game scripting", "risc-v emulation", "sandboxing untrusted code"], "compared": [{"slug": "deno", "name": "Deno", "co": 2, "switched_from": 0, "switched_to": 0}], "makers": [{"id": 759871440, "item_id": 47491965, "url": "https://news.ycombinator.com/item?id=47491965", "by": "fwsgonzo", "date": "2026-03-23", "stance": "recommend", "quote": "We present two implementations: libriscv (12-14ns overhead, emulated execution)", "excerpt": "I actually just published a paper about something like this, which I implemented in both libriscv and TinyKVM called \"Inter-Process Remote Execution (IPRE): Low-latency IPC/RPC using merged address spaces\". Here is the abstract: This paper introduces Inter-Process Remote Execution (IPRE), whose primary function is enabling gated persistence for per-request isolation architectures with microsecond-latency access to pe", "context": "author of IPRE paper", "use_case": "Emulated RISC-V execution", "switched_from": "", "story": "Show HN: Threadprocs \u2013 executables sharing one address space (0-copy pointers)"}], "threads": [{"url": "https://news.ycombinator.com/item?id=48987846", "title": "Running Doom on Our Custom CPU and Going Viral", "mentions": 1}, {"url": "https://news.ycombinator.com/item?id=48048902", "title": "Making your own programming language is easier than you think (but also harder)", "mentions": 1}, {"url": "https://news.ycombinator.com/item?id=47491414", "title": "Show HN: Threadprocs \u2013 executables sharing one address space (0-copy pointers)", "mentions": 1}, {"url": "https://news.ycombinator.com/item?id=47069876", "title": "Show HN: A Lisp where each function call runs a Docker container", "mentions": 1}, {"url": "https://news.ycombinator.com/item?id=46580136", "title": "FUSE is All You Need \u2013 Giving agents access to anything via filesystems", "mentions": 1}, {"url": "https://news.ycombinator.com/item?id=46375067", "title": "Show HN: LoongArch Userspace Emulator", "mentions": 1}], "sentiment_by_month": {"2025-11": {}, "2025-12": {"recommend": 1}, "2026-01": {"recommend": 1}, "2026-02": {"recommend": 1}, "2026-03": {}, "2026-04": {}, "2026-05": {"recommend": 1}, "2026-06": {}, "2026-07": {"recommend": 1}, "2026-08": {}, "2026-09": {}, "2026-10": {}}, "quotes": [{"id": 783844800, "item_id": 48990300, "url": "https://news.ycombinator.com/item?id=48990300", "by": "sph", "date": "2026-07-21", "stance": "recommend", "quote": "A very fast RISC-V VM with sandboxing of memory and syscalls.", "excerpt": "If you don't want to delegate the fun of learning to an LLM, here's how I've built a RV64IM simulator in C in a weekend. All you need is an opcode table, the RISC-V specs and to implement each instruction; the good thing of RISC CPUs is that instructions are very simple (i.e. pretty much everything is a variation of `dest = src1 OP src2`) and memory instructions are dedicated. The other cool thing is that there are n", "context": "", "use_case": "", "switched_from": "", "story": "Running Doom on Our Custom CPU and Going Viral"}, {"id": 769260960, "item_id": 48078810, "url": "https://news.ycombinator.com/item?id=48078810", "by": "Imustaskforhelp", "date": "2026-05-09", "stance": "recommend", "quote": "libriscv is one of the fastest libriscv emulators", "excerpt": "I have only read the first end of the article but I can't help but think that a project like libriscv[0] would've/could've worked for their game project too because fun fact but the creator of librsicv, the legendary fwsgonzo is also making a game. I highly recommend for people to check out their discord server. But my main point is that libriscv is one of the fastest libriscv emulators and then something like C/C++/", "context": "", "use_case": "sandboxed game scripting", "switched_from": "", "story": "Making your own programming language is easier than you think (but also harder)"}, {"id": 753174496, "item_id": 47073406, "url": "https://news.ycombinator.com/item?id=47073406", "by": "networked", "date": "2026-02-19", "stance": "recommend", "quote": "The author may like", "excerpt": "This is fun. The author may like https://skarnet.org/software/execline/ (can be containerized the same way?), https://github.com/darius/awklisp, and https://github.com/libriscv/libriscv + https://github.com/libriscv/libloong.", "context": "", "use_case": "", "switched_from": "", "story": "Show HN: A Lisp where each function call runs a Docker container"}, {"id": 745326945, "item_id": 46582934, "url": "https://news.ycombinator.com/item?id=46582934", "by": "Imustaskforhelp", "date": "2026-01-11", "stance": "recommend", "quote": "which is a sandbox (The fastest RISC-V sandbox)", "excerpt": "I recently had a question about what AI sandboxes use and I think Modal uses gvisor under the hood and I think others use firecracker/generally favour it as well Firecracker kind of ends up being in the VM categories and I would place gvisor in a similar category too under the VM So in my opinion, VM's are sandboxes. Of course there is also libriscv https://github.com/libriscv/libriscv which is a sandbox (The fastest", "context": "", "use_case": "", "switched_from": "", "story": "FUSE is All You Need \u2013 Giving agents access to anything via filesystems"}, {"id": 742644672, "item_id": 46415292, "url": "https://news.ycombinator.com/item?id=46415292", "by": "Imustaskforhelp", "date": "2025-12-28", "stance": "recommend", "quote": "I really appreciate libriscv", "excerpt": "Fwsgonzo, what a legend man!! I am not kidding but before seeing this post, I had commented about my experiences in the libriscv discord server (I am the person who had created the AUR arch repository for simplekvm but had to pull them down) For reference: https://news.ycombinator.com/item?id=46413053#46415223 Call this luck or whatever, but I really appreciate libriscv and I will definitely try to be more active, A ", "context": "", "use_case": "RISC-V emulation", "switched_from": "", "story": "Show HN: LoongArch Userspace Emulator"}, {"id": 741901040, "item_id": 46368815, "url": "https://news.ycombinator.com/item?id=46368815", "by": "Imustaskforhelp", "date": "2025-12-23", "stance": "recommend", "quote": "this has the least latency out of any sandbox at only minor consequence of performance that they know of", "excerpt": "I had been in a similar boat and here are some softwares that I recommend or would discuss with you https://github.com/libriscv/libriscv (I talked with the author of this project, amazing author fwsgonzo is amazing) and they told me that this has the least latency out of any sandbox at only minor consequence of performance that they know of Btw for sandboxing, kvm itself feels good too and I had discussed it with the", "context": "", "use_case": "sandboxing untrusted code", "switched_from": "", "story": "Fabrice Bellard Releases MicroQuickJS"}]}