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Dev tools · alternatives · 2026

24 alternatives to Mistle – Open-source infrastructure for running sandboxed coding agents

Hi HN, I'm Jonathan. My co-founder, Thomas, and I started building Mistle in Feb. We saw larger tech companies like Ramp (Inspect) and Stripe (Minions) build this internally and thought an open source version should exist. We made a few very intentional decisions when working on this: 1. Credentials are kept out of the sandbox. Authorized access goes through a proxy, so agents do not directly receive credentials. 2. The harness is not our problem. We're not going to tackle things like memory, self-learning. 3. No magic. Configurations are explicit. You can bring your own keys for models,…

Below are 24 products that do a similar job, ranked by how close each is in meaning and then by launch-day votes. Prices are shown for the 1 we have checked on their own sites, 1 of them free or with a free tier.

  1. 1

    Hello HN, I don't post on here much, but wanted to get some eyes on a new project I'm just launching. I think we definitely need one more AI code agent.. I'm a long-term C++ dev, and over 30+ years I've created some successful audio dev tools (JUCE, the Tracktion DAW, the Cmajor DSP language). All of these came from me getting annoyed with something I had to use, and deciding to have a go at my own take on whatever it was. So Juggler is my attempt at an AI code agent, after spending too many hours loving what the models could do, but hating the CLI experience, and having some opinions of…

    Jul 2026 · github.com · its alternatives →

  2. 2

    Hi there, Mike here from Budibase. We’ve recently launched AI Agents into Beta, alongside our existing open-source app-building and automation tools. We built Budibase Agents for teams that want to leverage AI within real-world workflows, using their own LLMs, data, and APIs. Because of this, our Agents can be powered by any LLM with an OpenAI-compatible API, including open-source and locally-hosted models. This means you can build Agents that connect to your existing toolstack, within your own environment. Some more details: - Agents' behavior is configured using natural language…

    2022 · budibase.com · its alternatives →

  3. 3

    Contribute to vrn21/bouvet.com development by creating an account on GitHub.

    Jan 2026 · github.com · its alternatives →

  4. 4
    Freebuff▲310

    Free coding agents to kill Claude, Cursor, Replit, and Devin

    Aug 2026 · freebuff.com · its alternatives →

  5. 5
    Buda▲197

    Run a full AI agent team in the cloud — no hardware, no setup. Persistent memory, browser automation, parallel agents. The OpenClaw alternative built for teams. Start free.

    May 2026 · buda.im · its alternatives →

  6. 6

    SOTA open-source agentic coding models and CLI agent

    Dec 2025 · mistral.ai · its alternatives →

  7. 7

    Agentic development environment built with the community

    May 2026 · github.com · its alternatives →

  8. 8
    Compyle▲125

    Hey HN! I'm Jonathan, one of the co-founders of <>> Compyle. We're building a coding agent that isn't afraid to stop and ask questions! It checks in with you before it makes key product and engineering decisions, so you can trust it with more open-ended tasks than you can with other coding agents. Before Compyle, we were building SmartAppetite (AI agents for insurance). Using tools like Claude Code &#x2F; Cursor, we had a demo in days - then spent weeks cleaning up a codebase we no longer fully understood. We had to pause feature development just to refactor. That pain is why we built…

    Nov 2025 · compyle.ai · its alternatives →

  9. 9

    OpenAgents - The collaboration OS for AI agents. Contribute to openagents-org/openagents development by creating an account on GitHub.

    Apr 2026 · open-agents.dev · its alternatives →

  10. 10

    Build production agents with harness and sandbox

    Apr 2026 · openai.com · its alternatives →

  11. 11
    OpenBox▲171

    See, verify, and govern every agent action.

    Apr 2026 · openbox.ai · its alternatives →

  12. 12
    Boxes.devfree tier, from $19/mo▲112

    Hi HN, we’re Nick and Drew, and we’re building boxes.dev – the first cloud-only agentic dev environment (ADE) that gives every Codex and Claude Code agent its own cloud computer. We’re two engineers who previously built Gem (co-founder&#x2F;CTO and first hire), and we spent the last year coding almost exclusively using Codex and Claude Code. It’s been a huge change to how we code, and it’s been exhilarating seeing the models keep getting better – but we eventually realized that developing on localhost was holding us back: - Git worktrees are clunky to set up and use for parallelizing work -…

    Jun 2026 · boxes.dev · its alternatives →

  13. 13

    Hello HN! The day has finally come to stop adding features and start sharing what I've been building the last 5-6 months. It's a bit of CrewAI, OpenDevon, LangFuse&#x2F;Cloud all in one, providing devs who prefer TypeScript an integrated framework thats provides a lot out of the box to start experimenting and building agents with. It started after peeking at the LangChain docs a few times and never liking the example code. I began experimenting with automating a simple Jira request from the engineering team to add an index to one of our Google Spanner databases (for context I'm the…

    2024 · github.com · its alternatives →

  14. 14

    Hi HN! Sina here. i wanted to share this open source project (apache 2.0) that i've been working on for the past month or so. it's called hotcell and it lets you create&#x2F;pause&#x2F;manage sandboxes on any device (your laptop, linux vm, bare metal). i've tested it against various benchmarks that i found on computesdk (https:&#x2F;&#x2F;www.computesdk.com&#x2F;benchmarks&#x2F;sandboxes&#x2F;) as well as the one shared by dax (cofounder of open code) on twitter recently (link to his original thread and my reply https:&#x2F;&#x2F;x.com&#x2F;sinasanm&#x2F;status&#x2F;2078158598996443346) and…

    Aug 2026 · github.com · its alternatives →

  15. 15

    I'm Josh, founder of Synth. We've been working on coding agent optimization with method like GEPA and MIPRO (the latter of which, I helped to originally develop), agent evaluation via methods like RLMs, and large scale deployment for training and inference. We've also worked on patterns for memory, processing live context, and managing agent actions, combining it all in a single stack called Horizons. With the release of OpenAI's Frontier and the consumer excitement around OpenClaw, we think the timing is right to release a v0. It integrates with our sdk for evaluation and optimization but…

    Feb 2026 · github.com · its alternatives →

  16. 161D

    We just open-sourced the internal system we built at Assembled for running coding agents as a team. Coding agents worked well for individual engineers, but the surrounding workflow was a bit of a mess. We generally found that many engineers had different MCP connections and context for their agents, personal automations running that other people couldn’t access, and very little introspection for what a human’s input into the coding agent looked like. So we built an internal system that converted coding agents into shared team infrastructure. The system runs Codex, Claude Code, OpenCode, and…

    Jun 2026 · its alternatives →

  17. 17

    We’ve been working with automating coding agents in sandboxes as of late. It’s bewildering how poorly standardized and difficult to use each agent varies between each other. We open-sourced the Sandbox Agent SDK based on tools we built internally to solve 3 problems: 1. Universal agent API: interact with any coding agent using the same API 2. Running agents inside the sandbox: Agent Sandbox provides a Rust binary that serves the universal agent API over HTTP, instead of having to futz with undocumented interfaces 3. Universal session schema: persisting sessions is always problematic, since…

    Jan 2026 · github.com · its alternatives →

  18. 18
    Code▲20

    Hey HN, Today we're launching Code, a community-driven, open-source coding agent for your terminal. It's a fork of OpenAI's codex with a focus on developer ergonomics and local control. Key features: - Browser integration – attach to your Chrome via CDP or use a built-in headless browser. You can browse pages, run the CLI in a browser session, and even take screenshots from the terminal. - Multi-agent commands – &#x2F;plan, &#x2F;solve and &#x2F;code orchestrate multiple models (ChatGPT, Claude, Gemini) to propose and implement solutions, with consensus or race options. - Diff viewer – see…

    2025 · github.com · its alternatives →

  19. 19

    Hi HN, I’m the creator of Cordum. I’ve been working in DevOps and infrastructure for years (currently in the fintech&#x2F;security space), and as I started playing with AI agents, I noticed a scary pattern. Most "safety" mechanisms rely on system prompts ("Please don't do X") or flimsy Python logic inside the agent itself. If we treat agents as autonomous employees, giving them root access and hoping they listen to instructions felt insane to me. I wanted a way to enforce hard constraints that the LLM cannot override, no matter how "jailbroken" it gets. So I built Cordum. It’s an open-source…

    Jan 2026 · github.com · its alternatives →

  20. 20
    Aether▲26

    Since coding agents like Claude Code and Codex came out, I've been pretty obsessed with them. It's hard not to when you're getting a 20x discount on inference. I've also been frustrated by them a lot. I hated walking around with my laptop lid open while connected to a hotspot on my phone, having to tediously accept commands so I don't lose my root directory, and running out of RAM when running multiple agents that were spinning up dev servers in different worktrees at once. A lot of people would say existing cloud agents are the solution to this, as none of the above problems apply to any…

    Jul 2026 · runaether.dev · its alternatives →

  21. 21

    A sandbox service for running untrusted, agent-authored code that reports the isolation boundary each run executed behind. Lessons, no clone needed: https://plimsollmark.github.io/plimsoll/trainers/ - plimsollmark/plimsoll

    10d ago · github.com · its alternatives →

  22. 22LA

    Hello HN, I am building a devtool to understand existing codebases. The idea originates from my time at big tech as well as various attempts to get involved in open source projects. When I was in college I wanted to improve my coding skills by contributing to opensource projects. I would pickup a bug or feature request but I always found myself stuck at the very first step. I did not understood where and how to begin contributing. I once submitted a patch in firefox which was labeled "Good first issue" but that was still very handheld. The assigner told me exactly which files I need to…

    2024 · lucidcode.ai · its alternatives →

  23. 23

    I love Claude Code but got tired of having nothing to do while I waited for sessions to finish, and managing multiple sessions on the command line was getting annoying and I kept losing track of the tabs. I originally built a quick and dirty version of this for my own use, but decided to polish it up and make it open source. The idea is that you should be able to do all your agentic coding without leaving the tool or needing to go back to a traditional IDE. You can view the diffs, run your program, and merge your changes back. I support OSX and Linux right now, but could add Windows support…

    2025 · github.com · its alternatives →

  24. 24OS

    Kshitij and Rahul here. We're building Playground, an open-source sandbox that lets your non-technical teams prototype directly on production codebases, without bugging you (developers) to spin up and maintain another repo. The repo is here: https:&#x2F;&#x2F;github.com&#x2F;B1u3B01t&#x2F;design-playground. We've been working together for six years. Last year we built an AI design agent because we thought designers were the biggest bottleneck. But we were wrong. After talking to teams, we realised designers, PMs, founders and even sales people all wanted to quickly change and explore flows…

    Jul 2026 · its alternatives →

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Ranked by how close each launch is in meaning, then by votes. Prices were read from each product’s own site when checked and can change. Refine with your own description →