# Butter

Official pricing: https://butter.dev  
Category: agent-sandbox · Isolation: gvisor

## Pricing regimes (raw)

- **Native product; see regime notes** (resource) [alt]

## Features

Yes: ≥24 h sessions, self-hosting, open source, arm64, Python, Node.js, gVisor or VM (no shared kernel)

No: snapshots, memory snapshots, fork/clone, pause/resume, persistent disk, volumes, idle auto-stop, custom image (Docker or snapshot), start from your own snapshot, your own Docker/OCI image, full VM (own kernel), Docker inside, nested virtualization, root, browser, desktop GUI, computer-use API, browser + desktop control, anti-bot stealth, CAPTCHA solving, preinstalled agents, SSH, public IPv4, HTTPS preview URLs, raw TCP inbound, egress allowlist, static egress IP, BYOC, SOC 2, HIPAA, SSO, GPU, Windows, macOS, HTTP method/path egress rules, wake on request, live resize, live fork (no pause), memory fork, EU data residency, MCP server, automatic snapshots, snapshots on demand, agent harness API, hosted agent API (their own agent), inbound access rules, firewall inside (nftables), secret proxy, secret proxy for any API, extra volumes, shared volumes

Unknown: everything else. Evidence (source + quote) per feature: https://battleships.dev/data/providers/butter.json → feature_evidence

## Caveats

- Current YC description explicitly local in-process safe bash, not remote VMs. Public runtime is relevant technology but no cloud compute sold is verified. Do not manufacture hosted tariff from a local library.
- Inventory exclusion: local runtime, not hosted compute. Card contains no numeric compute modes and no selectable price plan.
- Null values mean unknown, not free/unlimited. No model-token cost, tax or unverified ancillary charge included.
- Native browser/device/task/credit prices with unknown CPU/RAM are deliberately non-priceable. Check regime before interpreting any partial resource estimate.
- bVisor README: 'bVisor is an early proof-of-concept and should not yet be used in production.' TypeScript SDK only (npm 'bvisor'); Python SDK and CLI 'planned'. Isolation is seccomp-user-notifier syscall interception in-process (gVisor-inspired), not a VM or container; resource limits (cgroups) 'not started'. Last repo commit 2026-02-23 (about 7 months without activity).

## How this provider charges


YC: Winter 2025; directory status **Active**. Research scope: marginal-or-unavailable. Source: https://www.ycombinator.com/companies/butter

Embedded bVisor runtime

## Regime table

| Regime | When it applies | How billed | Numbers | Source |
|---|---|---|---|---|
| Native product; see regime notes | Incomplete or non-resource economics: rates remain null, never interpreted as free. | resource; CPU alloc, memory alloc | Unknown or native-unit billing; see facts below | https://butter.dev |
| Current applicable tariff unverified | Plan limits apply | Monthly fee; credits only as stated | fee=None; included usage=$None; concurrent=None; max session h=None | https://butter.dev |
| Retained disk / GiB-month | Lifecycle/scope must be checked | Native add-on | unverified, not $0 | https://butter.dev |
| Snapshots / GiB-month | Lifecycle/scope must be checked | Native add-on | unverified, not $0 | https://butter.dev |
| Egress / GiB | Lifecycle/scope must be checked | Native add-on | unverified, not $0 | https://butter.dev |
| IPv4 / month | Lifecycle/scope must be checked | Native add-on | unverified, not $0 | https://butter.dev |

## Verified billing facts and gotchas

1. Current YC description explicitly local in-process safe bash, not remote VMs. Public runtime is relevant technology but no cloud compute sold is verified. Do not manufacture hosted tariff from a local library.
2. Inventory exclusion: local runtime, not hosted compute. Card contains no numeric compute modes and no selectable price plan.

## Worked example

Requested: 4 vCPU/8 GiB, 50 simultaneous × 8 h/day × 22 days = **8,800 instance-hours**, 30% CPU; 50 GiB snapshots and 100 GiB egress. A month is 730 hours only when explicitly used in rate conversion.

**Total: unknown.** This product does not publish a verified complete 4-vCPU/8-GiB tariff and/or the service bills a different unit. Fifty concurrent instances and eight-hour sessions are not automatically supported. Neither 30% utilization nor retained snapshots can be converted into free resources. Use the native plan terms above and request the missing CPU/RAM, retention, egress and concurrency quote.

## Sources and coverage

- https://www.ycombinator.com/companies/butter

Page captures and documentation indexes/bundles are in `raw/`; provider JSON lists the evidence paths. HN query results were captured separately as `<id>--hn.txt`; they are discovery leads, not current tariff authority. Downloaded docs do not imply every feature was verified; unsupported assertions remain null.