AI tool comparison
CrabTrap vs smolvm
Which one should you ship with? Here is the side-by-side panel verdict, pricing read, reviewer split, and community vote comparison.
Developer Tools
CrabTrap
Open-source HTTP proxy that enforces security policies on AI agent API calls
50%
Panel ship
—
Community
Paid
Entry
CrabTrap is an open-source HTTP/HTTPS proxy built by Brex's engineering team that sits between AI agents and the external internet, evaluating every outbound request against configurable security policies before it reaches any third-party API. It uses a two-tier evaluation system: fast deterministic static rules handle the obvious cases (block this domain, require this header), while an LLM-as-a-judge handles ambiguous requests that need semantic understanding — like determining whether a request to send an email is within scope of the current task. Built in Go with a TypeScript frontend, CrabTrap ships with a PostgreSQL-backed audit log and a web UI for policy management. It supports MITM inspection of HTTPS traffic, request/response logging, and policy versioning — making it suitable for production agentic systems where compliance or security teams need a paper trail. Version 0.0.1 was released April 17, 2026 and is MIT licensed. The problem it solves is real: as AI agents gain more autonomy and access to external APIs, the attack surface grows. A compromised or misbehaving agent that can freely call any URL is a significant risk. CrabTrap gives engineering teams a single chokepoint to enforce least-privilege access — something that's been missing from most agentic frameworks that assume a trusted execution environment.
Developer Tools
smolvm
Ship portable Linux VMs that boot in under 200ms — isolation by default
75%
Panel ship
—
Community
Paid
Entry
smolvm is a Rust-based CLI tool for building, running, and distributing lightweight Linux virtual machines with sub-second cold starts. Born from the smol-machines project, it addresses a gap in the developer toolchain: running untrusted code or reproducible environments without the overhead of Docker daemons or full hypervisors. A single "Smolfile" TOML config declares your VM, and state packs into a portable .smolmachine file you can share across macOS and Linux. Under the hood, smolvm uses libkrun VMM with Hypervisor.framework on macOS and KVM on Linux. Memory is elastic via virtio balloon, so the host reclaims unused RAM. Network is off by default — a deliberate security stance. SSH agent forwarding works without exposing private keys to guest VMs. OCI image compatibility means you can pull from Docker Hub or ghcr.io without modification. The key use case shaping community interest is sandboxing AI agent workloads: give agents a hardware-isolated VM that boots in under 200ms with configurable filesystem and egress constraints. With AI coding tools increasingly executing arbitrary code, smolvm fills a meaningful gap between "run it on bare metal" and "stand up a full Kubernetes pod." At 2.2k GitHub stars and 487 HN upvotes on the day of its Show HN post, developer traction is real.
Reviewer scorecard
“This fills a gap that every production agentic system needs but almost no one has solved yet. The two-tier policy engine — static rules for speed, LLM for ambiguity — is the right architecture. The fact that Brex built and open-sourced this suggests they've already battle-tested it against real agent deployments.”
“This solves the AI agent sandbox problem cleanly. Sub-200ms boot, declarative Smolfile config, and OCI compatibility means you can integrate it into a CI pipeline in an afternoon. The network-off-by-default stance is exactly right — I want to opt into exposure, not opt out.”
“v0.0.1 with 126 GitHub stars is a weekend project right now, not infrastructure you should bet your production agents on. The LLM-as-a-judge for policy evaluation is also expensive and introduces its own latency — you're adding an AI call to evaluate every AI agent call. The operational complexity of running MITM HTTPS inspection in production is non-trivial.”
“It's alpha-quality infrastructure with 2.2k stars and a tiny team. Running production AI workloads in a project with 84 forks and no enterprise backing is a gamble. The macOS/Linux-only support also cuts out anyone running Windows-based CI, which is a real limitation for enterprise adoption.”
“Agent security tooling is where network security tooling was in the early 2000s — primitive, fragmented, and urgently needed. CrabTrap is an early bet on a category that will be worth billions once enterprises start mandating audit trails for agentic systems. Brex building this in-house and open-sourcing it is a strong signal of what production agent operators actually need.”
“As AI agents become default executors of arbitrary code, hardware-isolated sandboxes become load-bearing infrastructure, not optional hardening. smolvm's portable .smolmachine format is the right abstraction — the 'Docker image for VMs' primitive that the agent ecosystem has been missing.”
“This is deeply in the DevOps/infrastructure lane — not something a creator or designer would ever touch directly. But if the tools you use to generate content are backed by CrabTrap-style security, you'd want that. For now, it's a ship for the engineers who configure your AI stack, a skip for everyone else.”
“For anyone running code-gen tools or AI pipelines that touch the filesystem, this is peace of mind packaged in a CLI. The Smolfile config feels approachable, and the fact you can email a .smolmachine file and have it boot identically on a colleague's Mac is genuinely delightful.”
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