Code & AI agent sandboxes: read the guide

Runtime

HostedSandbox

Linux sandboxes for AI agents

Homepage Docs Pricing

Scanned 15 Oct 2026 · Schema v5 · features v21

From: Free
prepaid usage-based
Free tier: Yes
No card required.
Isolation: Firecracker microVM
shares only the hypervisor
Regions: 1
Virginia, United States
Capabilities: 30 / 61
1 partial · 30 fail · 0 not assessed
Agent readiness: 11/11 · 10/11
read · drive, pre-login surface

Advertised for

Agent generated code execution · Persistent agent workspaces · Code interpretation · Desktop/browser automation · Sandbox hosted MCP tools · Scheduled isolated jobs · Preview and web services

Built for

Developers, then technical

· API/SDK/CLI/MCP-led Linux sandbox provisioning
· Active vCPU and reserved GiB-hour pricing
· Deep networking, identity, lifecycle and isolation reference docs

01 Pricing prepaid usage-based

Tier	EntryPrepaid usage (no plan tiers)
Price	No plan fee; CPU $0.025/active vCPU-hour + memory $0.0075/GiB-hour
Transfer	107.3741824 GB
vCPU hours	25 h
Memory gb hours	100 h
Transfer overage	$0.02/GB
vCPU hours overage	$0.025/h
Memory gb hours overage	$0.0075/h

active vCPU-hour + reserved GiB-hour; storage and network separately metered·Card required: No·withruntime.com

Overages: CPU $0.025/active vCPU-hour; memory $0.0075/reserved GiB-hour; outbound above 100 GiB/month $0.02/decimal GB; separate storage rates

02 Website design Desktop public website · assessed 15 Oct 2026

Complete assessment.

A restrained, near-monochrome desktop website pairs large, tightly tracked sans-serif headlines with generous whitespace, rounded surfaces and pill-shaped controls. The landing page uses a two-column illustrated comparison, pricing adopts a narrow editorial article and table, and documentation uses a sidebar with orderly card grids.

Editorial minimalism
Swiss-inspired

Landing page: captured
Pricing: captured
Docs: captured

03 Runtime Each fact carries its source; dots show confidence. Open a row for the evidence.

Isolation & lifecycle

Isolation primitive

Firecracker microVMshares only the hypervisor

Persistence

Disk survives stop/restart; paid pause preserves RAM while credit lasts; independent volumes outlive sandboxes.

Snapshots / forks

Forks and snapshots retain files, memory and running processes; 1–10 running fork copies.

Resources & limits

Storage

Persistent sandbox disk, attachable volumes with daily/on-demand off-server backups, kept snapshots copied off-server; mount your own S3/R2/GCS buckets.

Limits & quotas

Without credit: 4 concurrent, 2 vCPU/4 GiB/10 GiB disk each, 8 vCPU/16 GiB total, 10 retained sandboxes, 50 creates/day. Funded: 100 concurrent (200 with auto top-up), up to 16 vCPU/64 GiB/400 GiB disk each; 200 aggregate vCPU/400 GiB RAM, doubled with auto top-up.

GPU

Access

Deploy interface

apiclisdkmcpdockerfileoci-image

SDK languages

JavaScriptTypeScriptPythonGoRubyJava

Network & secrets

Egress controls

Per-sandbox allow/deny rules and internet-off; default public-network restrictions; dedicated outbound IP with funded account.

Secrets

Host-side HTTPS proxy swaps placeholders for credentials only on approved hosts; sandbox never receives the real value.

Bring your own cloud

Placement & use

Jurisdiction

United States; Colorado law and Denver courts/arbitration

Advertised workloads

Agent generated code executionPersistent agent workspacesCode interpretationDesktop/browser automationSandbox hosted MCP toolsScheduled isolated jobsPreview and web services

04 Capabilities 30 pass · 1 partial · 30 fail · 61 of 61 assessed

Supported — Documented on the public surface and verified.
Partially supported — Exists with caveats: gated, thin, or enterprise-only.
Not supported — Checked and not offered.
Not assessed — Scanned before this capability was tracked. Not a lack.

Compute & storage 6/11

Persistent diskStorage that survives restart/stop (not ephemeral-only).

Supported

Object storageManaged S3-compatible / blob object store the platform PROVIDES to a user's workloads (buckets, presigned URLs). DISTINCT from persistent-disk (block/volume attached to an instance) and from a self-host dependency (source.self_host.deps[]=["object-storage"] is an infra dep to RUN an OSS tool — the opposite direction). SCOPE varies and matters: native first-class (Railway Buckets, Cloudflare R2) vs a sibling SKU / extension (Fly Tigris, Bunny Storage, DigitalOcean Spaces) — record which in the evidence quote / note. Admitted v15.

Not supported

Snapshots / forkingSnapshot or copy-on-write fork of a running instance (filesystem-only counts). Whether the snapshot also restores memory + running processes is recorded separately by memory-snapshot (v19).

Supported

Live-state (memory) snapshotsA snapshot / checkpoint / pause captures a running instance's MEMORY and PROCESS state and restores it, so running processes continue where they left off instead of a freshly booted instance with the same files. Counts whether user-triggered (snapshot, checkpoint, pause-to-storage) or used to restore pre-initialised state (memory snapshots for fast cold starts). Distinct from snapshots-forks (any snapshot or fork, including filesystem-only; a product passing that key may still fail this one) and from scale-to-zero (an idle-cost property; suspension may or may not keep memory). Actor multiplexing (see scale-to-zero) records its live-state half here — only when the suspended actor's MEMORY/process state is what comes back, not a freshly booted worker with the actor's files.

Supported

Scale to zeroIdle instances suspend at no / negligible cost. ACTOR MULTIPLEXING (many suspended stateful actors sharing a small pool of pre-warmed workers, woken on request — Agent Substrate, AX, kagent; Rivet's hibernating actors) has NO key of its own (proposal REJECTED v20) — score the idle-cost half HERE and the live-state half under memory-snapshot; the oversubscription ratio / density is a performance characteristic the registry does not key.

Supported

GPU computeGPU-backed instances available.

Not supported

Multi-regionCompute placeable in more than one geographic region.

Not supported

Sandbox templates / custom imagesBuild reusable sandbox/VM images from an OCI image or Dockerfile (a base you fork instances from).

Supported

Cloud-init / ignition configCustomise a VM / microVM / instance at boot via cloud-init (or ignition) user-data — the same boot-metadata interface as AWS/Azure/GCP. Inject packages, users, SSH keys, files, and run-commands declaratively at launch. Distinct from sandbox-templates (a PREBUILT image you fork instances from) — this is PER-LAUNCH declarative customisation, not a baked image.

Not supported

Desktop / computer-use sandboxA virtual desktop (GUI) for LLM computer-use — browser + desktop automation, often via noVNC/VNC.

Supported

Selectable isolation runtimeThe user chooses the isolation runtime per workload / environment / sandbox from more than one option (e.g. microVM vs gVisor vs plain container, native namespaces vs gVisor, gVisor vs VM). Records the CHOICE; the isolation_primitive facet still records the best-evidenced primary. A platform that switches runtime automatically without a user choice (e.g. gVisor forced for GPU) does not pass on that alone.

Not supported

Networking & delivery 6/9

Automatic HTTPSTLS endpoints provisioned automatically per workload.

Supported

Built-in reverse proxyPlatform routes external traffic to workload services.

Supported

Custom domainsBring-your-own domain via CNAME/DNS.

Supported

Public preview URLsShareable per-deploy / per-branch URLs.

Supported

Direct public IPv6Per-instance stable public IPv6 for raw TCP/UDP (beyond a managed HTTPS proxy) — e.g. mosh / raw sockets.

Not supported

Egress controlsConfigurable OUTBOUND network policy — egress firewall / allowlist / egress proxy on traffic LEAVING a workload. Scoped to OUTBOUND only (v15): private-network REACHABILITY between a user's own services is private-networking, not this. Static-egress-IP belongs here (an outbound concept).

Supported

Private networkingA platform-internal private network between a user's OWN services — service-to-service connectivity, VPC, service mesh, and/or service discovery, not exposed to the public internet. DISTINCT from egress-controls (OUTBOUND firewall/allowlist), reverse-proxy (PUBLIC inbound ingress), and direct-ipv6 (per-instance PUBLIC addressing). Admitted v15.

Supported

Email send / receiveSend and/or receive email from the workload.

Not supported

Edge KV storeA globally-replicated key-value store read from WITHIN an edge runtime at the PoP (low-latency, eventually-consistent) — Cloudflare Workers KV, Deno KV, Fastly KV Store, Akamai EdgeKV, Vercel Edge Config. Distinct from first-party-db (a managed DATABASE service you provision and connect to) and from http-query-api (HTTP access to an external store) — edge-kv is colocated with the edge compute and read at the edge.

Not supported

Developer access 6/10

Public APIDocumented programmatic API.

Supported

OpenAPI specMachine-readable OpenAPI / Swagger spec published.

Supported

CLIOfficial command-line tool.

Supported

SDKOfficial client library/libraries.

Supported

SSH accessDirect SSH into workloads.

Supported

Filesystem APIRemote file operations over the API (list/read/write/watch/copy/upload) without SSH.

Supported

Git deployDeploy from a Git repo / push-to-deploy.

Not supported

Private container registryHosted private image registry.

Not supported

E2B-compatible APIDrop-in compatibility with the E2B sandbox API/SDKs — existing E2B client code runs against this product by changing the endpoint/domain + key, with no business-code changes. E2B itself passes as the reference implementation. Distinct from public-api / sdk (the product has its own API — this key says it also speaks another vendor's) and from self-host-oss (a self-hosted E2B-compatible server is scored on both).

Partially supported

HTTP data APIQuery / read / write the stored DATA over plain HTTP/REST (or GraphQL) WITHOUT the native protocol driver (Postgres wire / Redis RESP) — agent- and edge-friendly data access via fetch(). The DATA plane; distinct from public-api (a control-plane / management API). Auto-generated-from-schema REST/GraphQL (PostgREST, pg_graphql) is a flavour of this.

Not supported

AI & agents 5/12

Built-in coding agentShips a first-party AI coding agent in the product.

Not supported

Agent skillsInstallable / declarable agent skills or tools.

Supported

AI app builderPrompt-to-app / vibe-coding generation surface.

Not supported

MCP serverExposes a Model Context Protocol server for agents.

Supported

MCP clientActs as an MCP client / consumes MCP tools.

Not supported

MCP-server hostingRun/host MCP servers as a workload on the platform (distinct from exposing a first-party MCP control server — that is mcp-server).

Supported

LLM gatewayRoutes LLM API calls through the platform (multi-provider).

Not supported

BYOK for LLMsBring-your-own LLM provider keys.

Supported

Model inference API (first-party)A FIRST-PARTY hosted LLM/model inference API — the provider serves its OWN catalogue of (usually open-weight) models behind a (typically OpenAI-compatible) endpoint, billed per token. Distinct from llm-gateway (a multi-PROVIDER proxy/router for YOUR calls to external providers like OpenAI/Anthropic) and from byok-llm (bring your own provider keys) — here the platform IS the inference provider, serving its own models.

Not supported

Autonomous QA agentA first-party AUTONOMOUS AI agent that QA-TESTS a running app / implementation — exercising it like a real user (clicking through flows, checking behaviour) and reporting bugs/defects (often back to a coding agent, or before a human review). Distinct from built-in-agent (a code-AUTHORING agent — this one VERIFIES the result, it does not write the feature; a product can ship both), from ai-guided-code-review (organises a diff for a HUMAN to review — not an autonomous tester), and from observability (runtime metrics/logs, not active testing).

Not supported

Credential-injection proxyThe platform holds real secrets OUTSIDE the workload and injects them on the wire (an egress / broker proxy swaps a placeholder or phantom token for the real credential on matching outbound requests), so code running in the sandbox — e.g. an untrusted agent — never sees or can exfiltrate the real key. Distinct from secrets-management (storage + injection INTO the workload as env vars/files — the workload holds the secret) and from egress-controls (outbound allow/deny POLICY; a product can have an allowlist without injecting credentials, and vice versa).

Supported

Preinstalled coding agentThe platform installs and launches a THIRD-PARTY coding agent (a harnesses.yml entry — Claude Code, Codex, OpenCode, Pi ...) inside a workspace/sandbox it provisions, with the agent's auth wired in (your own account or API key), so you start an agent session rather than an empty box. Distinct from built-in-agent (a FIRST-PARTY agent the vendor ships) and from harnesses[] (which records that a harness CAN target the product, not that the product runs it for you).

Not supported

Data 0/4

First-party databasePlatform-provided managed database.

Not supported

Database branchingCopy-on-write branch of a DATABASE (schema + data) as a dev-lifecycle primitive — branch your data like code, usually instant via a metadata operation. Distinct from snapshots-forks (forks a running compute INSTANCE / VM state) and from preview-environments (a full per-PR environment that may USE a DB branch). For a data product a CoW branch maps HERE, not to snapshots-forks.

Not supported

Vector searchFirst-class storage, indexing, and similarity search of vector embeddings — a native vector type/index or a managed vector DB. The data-layer primitive for RAG / semantic retrieval.

Not supported

Ephemeral instant DB (no-signup)Provision a working, usable instance via a single command / HTTP call with NO account, signup, or card — typically time-boxed (expires unless claimed). A zero-onboarding path an agent can hit directly.

Not supported

Platform & operations 2/6

Scheduled tasksCron / scheduled job primitive.

Supported

Durable workflowsDurable execution / long-running workflow primitive.

Not supported

Preview environmentsA full EPHEMERAL environment spun up per PR / branch — compute + addons + (often) a DB branch — torn down on merge. More than preview-urls (which is just a shareable URL for one deploy).

Not supported

Built-in observabilityFirst-party metrics / logs / tracing / APM / profiling included in the platform (no third-party stack required to see what a workload is doing).

Supported

Managed CI/CD runnersPlatform-hosted, drop-in CI/CD runner VMs (GitHub Actions / GitLab), typically faster and cheaper than the CI vendor's own hosted runners, billed per runner-minute; isolated + ephemeral per job. Distinct from git-deploy (push-to-deploy of an APP) and scheduled-tasks (cron) — this is managed CI COMPUTE you point your existing pipelines at.

Not supported

Project template marketplaceA marketplace / gallery of prebuilt PROJECT STARTER templates (apps or websites) a user clones or launches a new project from and then customises — the "start from a template" surface of a builder / PaaS. Distinct from sandbox-templates (a COMPUTE base IMAGE you fork runtime INSTANCES from — Dockerfile / OCI), from app-builder (the prompt-to-app GENERATION surface — a product can have both), and from one-click OSS-app catalogues / helm-addon-marketplace (deploy a FINISHED app as-is, not a starter you build on).

Not supported

Organisation & security 5/9

Built-in authPlatform-provided authentication / IAM for workloads.

Not supported

SSO / SAMLEnterprise single sign-on.

Supported

Secrets managementFirst-class secrets storage / injection.

Supported

TeamsMulti-user team accounts.

Supported

SharingShare a running workload/resource via link (optionally gated).

Supported

BYOCRuns inside the customer's own cloud account.

Not supported

Deploy into customers' VPCsA SaaS vendor uses the platform to deploy and operate ITS software inside ITS CUSTOMERS' cloud accounts / VPCs (nested or "customer BYOC"), managed from the vendor's control plane. Distinct from byoc (your own workloads in your own cloud account).

Not supported

Workload identityThe platform gives each workload its own verifiable identity (OIDC token, SPIFFE SVID, cloud IAM federation) that it exchanges for short-lived credentials, so no long-lived static secret is stored or injected. Distinct from secrets-management (stores / injects static secrets) and credential-injection-proxy (swaps real secrets in on the wire).

Supported

Self-host / OSS coreOpen-source core that can be self-hosted.

Not supported

05 Agent readiness Pre-login surface · counts, not a grade

Can an agent read it?

parse-ability · docs, metadata, machine-readable surfaces

11/11

9 full · 2 partial · 100% of applicable checks

llms.txt
Supported
“https://withruntime.com/llms.txt — substantive product, SDK, docs and pricing index; retained.”
llms-full.txt
Supported
“https://withruntime.com/llms-full.txt — HTTP 200 text/plain; 964,093-byte documentation corpus; bounded pointer retained.”
robots.txt AI policy
Partially supported
“https://withruntime.com/robots.txt — User-Agent: * Allow: /; no AI-specific named policy. /admin, /api/, /account disallowed.”
JSON-LD
Supported
“https://withruntime.com — SoftwareApplication Runtime Sandbox with description, featureList and Offer pricing; homepage-audit.json retains parsed JSON-LD.”
Sitemap
Supported
“https://withruntime.com/sitemap.xml — substantive multi-page URL index, linked in robots.txt.”
Meta tags
Supported
“https://withruntime.com — descriptive title, meta description and full OG URL/title/description/image/site metadata; actual HTML audit retained.”
Markdown negotiation
Supported
“https://withruntime.com — Accept: text/markdown returns clean Markdown; https://withruntime.com/docs/api.md also returns Markdown. Default programmatic homepage response is itself Markdown.”
Content efficiency
Partially supported
“https://withruntime.com — actual server HTML 268,656 bytes; extracted readable text 9,805 bytes; ratio 3.6496%, excluding scripts/styles. Default Markdown is not used as HTML denominator.”
Docs discoverable
Supported
“https://withruntime.com — Docs first-class header navigation; landing screenshot and HTML show link.”
Machine-readable pricing
Supported
“https://withruntime.com/pricing — structured resource price table; source Markdown includes rates and allowances, not contact-only prose.”
No anti-bot wall
Supported
“Public landing, docs, pricing and linked API specification fetched without challenge. Sign-in/network-based free-usage restrictions are not blocks on public docs.”

Can an agent drive it?

act-ability · APIs, SDKs, MCP, credentials, webhooks

10/11

10 full · 0 partial · 91% of applicable checks

Public API
Supported
“https://withruntime.com/docs/api — documented versioned HTTPS API at https://api.withruntime.com.”
OpenAPI spec
Supported
“https://api.withruntime.com/v1/openapi.json — fetched HTTP 200, valid OpenAPI 3.1.0; pointer and response metadata retained.”
MCP server
Supported
“https://withruntime.com/docs/mcp — documented https://api.withruntime.com/mcp Streamable HTTP plus npx -y withruntime mcp bridge.”
SDK packages
Supported
“https://withruntime.com/docs — official JavaScript/TypeScript, Python, Go, Ruby, Java SDK docs/packages.”
Auth documented
Supported
“https://withruntime.com/docs/api and https://withruntime.com/docs/security — bearer tokens, sessions, owner/admin-only account-wide keys and scoped access; OAuth/device approval documented.”
Self-serve credentials
Supported
“https://withruntime.com/docs/api — full-access owner/admin key can create/list/revoke /v1/keys. https://withruntime.com/llms.txt also documents paid wallet-only agent account creation; no purchase or account opening attempted.”
Webhooks
Supported
“https://withruntime.com/docs/observability — Runtime-Signature: t=...,v1=...; HMAC-SHA256 of {t}.{body}, five-minute replay window and SDK verification.”
CLI tool
Supported
“https://withruntime.com/docs/cli — official npx withruntime CLI with JSON output and product subcommands.”
Error model
Supported
“https://withruntime.com/docs/api — structured error {code,status,message,details}; x-request-id and status/code taxonomy.”
Rate limits documented
Supported
“https://withruntime.com/docs/api — about 50 requests/s per key, burst 200, per-account/in-flight limits; 429 Retry-After.”
Agent config files
Not supported
“https://withruntime.com/agents.md and https://withruntime.com/.well-known/agent return HTML 404; no installable configuration/skill listing found in inspected docs. Framework tool SDKs and llms.txt are captured separately, not invented as these configuration discovery files.”

06 Coding harnesses Which agents and IDEs are documented to run here

Advertised integrations 7

Claude Code Anthropic
Supported
“Claude Code, Codex, Cursor, Windsurf, VS Code, Gemini CLI and any other MCP client connect to Runtime's own MCP server, which offers every Runtime product as tools.”
Source withruntime.com
Codex CLI OpenAI
Supported
“Claude Code, Codex, Cursor, Windsurf, VS Code, Gemini CLI and any other MCP client connect to Runtime's own MCP server, which offers every Runtime product as tools.”
Source withruntime.com
Cursor Anysphere
Supported
“Claude Code, Codex, Cursor, Windsurf, VS Code, Gemini CLI and any other MCP client connect to Runtime's own MCP server, which offers every Runtime product as tools.”
Source withruntime.com
Windsurf Codeium
Supported
“Claude Code, Codex, Cursor, Windsurf, VS Code, Gemini CLI and any other MCP client connect to Runtime's own MCP server, which offers every Runtime product as tools.”
Source withruntime.com
Gemini CLI Google
Supported
“Claude Code, Codex, Cursor, Windsurf, VS Code, Gemini CLI and any other MCP client connect to Runtime's own MCP server, which offers every Runtime product as tools.”
Source withruntime.com
OpenCode opencode
Supported
“createRuntimeSandbox() runs Claude Code, Codex, OpenCode or Pi under HarnessAgent”
Source withruntime.com
Pi earendil-works
Supported
“createRuntimeSandbox() runs Claude Code, Codex, OpenCode or Pi under HarnessAgent”
Source withruntime.com

Plausible compatibility 10

Derived, not stored: the product passes SSH access, so any CLI coding agent is installable inside it. This is plausible compatibility, not a supported integration.

Aider
Amp
Antigravity
Devin
Droid
Goose
Hermes Agent
Kilo Code
Kiro CLI
Qwen Code

07 Compliance & regions Standards held, with ordinal rigor; never a score

Certifications held 0

Official trust page attributes certifications to infrastructure/data-center subprocessors, not Runtime LLC. Table column is "Their certifications, checked 27 September 2026"; sandbox data center has "SOC 1, SOC 2 and SOC 3 Type 2; ISO 27001". No provider-level held certification was established on reviewed official pages. Privacy promises SCC-based transfers. Do not promote supplier certifications into Runtime certified rows.

Regions 1

Virginia, United StatesVirginia

Trust: Everything runs in one region, in Virginia, United States. Subprocessors identifies sandbox dedicated server provider as OVH US LLC (OVHcloud US). Legal jurisdiction Colorado, not a second compute region.

Legal

Privacy notice Terms of service

08 Company & presence Facts only, not scored

Company

Headquarters: Not disclosed
Founded: —
Team size: Not disclosed
Hiring: unknown

Activity

Last release: 2026-10-15 withruntime.com
Last blog post: 2026-10-10 withruntime.com

Presence 3

Links found on the public surface scanned; not an exhaustive search.

09 Sources & method How this entry was produced

Public surface only

Everything here was read from withruntime.com's unauthenticated pages, docs, pricing and repository on 15 Oct 2026. Nothing behind a login was used.

Statuses, not scores

Capabilities are pass, partial or fail against a written rubric (features v21). “Not assessed” means the scan predates the key.

Confidence is separate

Each fact carries its own confidence. Low-confidence facts are shown, never hidden, so you can weigh them.

Schema: scan v5
Features registry: v21
Keys tracked today: 61
Assessed on this entry: 61

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