# Celesto (formerly SmolVM) vs E2B (slim)

> E2B scores 70.1 (BB) to Celesto's 68 (B) for code sandboxes. Prices, MCP, x402, uptime and agent notes side by side.

- Full: https://www.anchorterminal.com/compare/celesto-vs-e2b.md (~4,800 tokens) · this version ~2,480 tokens · JSON https://www.anchorterminal.com/compare/celesto-vs-e2b.json · canonical https://www.anchorterminal.com/compare/celesto-vs-e2b
- Index: https://www.anchorterminal.com/llms.txt · API: https://www.anchorterminal.com/api/v1/index.json · MCP: https://www.anchorterminal.com/mcp · Updated: 2026-11-07
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E2B scores 70.1 (BB) on agent readiness against Celesto (formerly SmolVM)'s 68 (B), and leads in 5 of 7 scored categories. Celesto (formerly SmolVM) leads on payments & pricing. Both do code sandboxes.

- Celesto (formerly SmolVM): B 68, rank #298 of 1486 · https://www.anchorterminal.com/tools/celesto.min.md
- E2B: BB 70.1, rank #214 of 1486 · https://www.anchorterminal.com/tools/e2b.min.md
- Celesto (formerly SmolVM), good for Local microVM sandboxes for agent code, browsers and desktops on Linux and macOS, with a path to a hosted cloud. Ahead on Payments & pricing, 60 against 50. Also No key needed to call it; No incidents deducted, where E2B loses 3 points for them.
- E2B, good for Code interpreters and agent workspaces that pause and resume with memory, and teams that may want to self-host later. Ahead on Reliability, 77 against 66; Schema & documentation, 92 against 85; Security & auth, 62 against 52; Maintenance & community, 93 against 81. Also Agent-ready, a grade of BB or better; A hosted endpoint, with nothing to install.

| Category | Celesto (formerly SmolVM) | E2B |
| --- | --- | --- |
| Reliability (16%) | 66 | 77 |
| Performance (10%) | pending | pending |
| Schema & documentation (13%) | 85 | 92 |
| Agent ergonomics (13%) | 69 | 70 |
| Security & auth (14%) | 52 | 62 |
| Payments & pricing (10%) | 60 | 50 |
| Task success (10%) | pending | pending |
| Maintenance & community (7%) | 81 | 93 |
| Transparency & trust (7%) | 70 | 70 |

| Fact (where they differ) | Celesto (formerly SmolVM) | E2B |
| --- | --- | --- |
| Kind | SDK + MCP | HTTP API |
| Vendor | Celesto AI, Inc. | E2B |
| Hosted endpoint | no (local only) | `https://api.e2b.app` |
| Transports |  | HTTP |
| Auth | None | API key |
| Last release | 2026-11-05 | 2026-10-28 |
| Terms last updated | 2026-10-30 | 2024-12-04 |
| Privacy policy last updated | 2026-10-30 | 2024-04-08 |
| Terms restrict benchmarking | not found in the text | yes |
| Terms or service can change without notice | not found in the text | yes |
| Arbitration or class-action waiver | not found in the text | yes |
| Popularity | 1.1k stars, 699 PyPI/wk | 13k stars, 2.2M npm/wk, 1.4M PyPI/wk |
| Agent reviews | none | 3/5 (2) |

Why the edge:
- Maintenance & community, E2B +12: Celesto (formerly SmolVM) 81 (0.1.13 on PyPI on 5 November 2026, tagged 6 November (30). 22 PyPI releases in the 90 days to 6 November (20). Most open issues are filed by maintainers. Outside reports such as the thread-safety issue got replies, and several recent ones have none yet; pull-request reply times were not read (15 of 25). The Python SDK is current, the TypeScript SDK is an alpha not published to npm (8 of 15). uv and Cargo lock files, CodeQL and publish workflows, with run results unread (8 of 10). Total 81.); E2B 93 (e2b 2.62.0 tagged on 28 October 2026 in both SDKs (30). 13 weekly dated changelog entries from 3 August to 26 October, and 30 JavaScript `e2b` tags and 33 Python SDK tags since 3 August (20). Per the 1 October check, 25 open issues against 12,900 stars; GitHub's issue pages couldn't be read on 1 November (18). Current official Python and JavaScript SDKs (15). Test workflows for every package on pull requests, lint and type checks, and dependency CVE bumps merged through 30 October (10). The 1 October note gave 5 because CI wasn't checked.)
- Reliability, E2B +11: Celesto (formerly SmolVM) 66 (Read with the local-software lines, because the graded surface runs on the owner's machine. Installs from PyPI as `celesto` with Python 3.11 or newer on Linux and macOS stated, plus an install script (20). The repository has pytest, e2e, lint, TypeScript and smoke-test workflows and 38 test packages, but GitHub's API answered with a rate limit, so no run result was read (15 of 25, unchecked). 22 open issues and pull requests against about 188 commits in 90 days. The open bugs include a snapshot restore that can lose a VM's disk if interrupted and a thread-safety issue with five replies (18 of 25). A dated changelog with Security, Fixed, Added and Removed sections, and the rename to Celesto marked as a breaking release, though versions stay below 1.0 (13 of 15). Pre-1.0 per SECURITY.md (0). Total 66.); E2B 77 (Status page at status.e2b.dev (incident.io) with component and region history (20). Its feed and history page, read on 1 November 2026, list 16 incidents from 4 August to 29 October. Each hit one component, one region or a share of requests, so all count as minor. The longest, 3 September (23:48 on 2 September to 02:28 UTC per the postmortem, posted as two incidents, with "a portion of sandbox creation requests" failing and other sandbox traffic succeeding) and 15 September (16:53 to 21:01 UTC, "some teams" creating sandboxes from snapshots), were read as majors on 1 October. 20 August was a Google Cloud incident in the US region affecting under 1 per cent of resumes, and the 27 and 29 October incidents were on US-West-1 only. Minor incidents only (20). Rate limits published per endpoint, 10 requests a second on Hobby and 20 on Pro, with sandbox creation at 1 and 5 a second (15). 429s carry `Retry-After` and the SDKs retry them from 2.49.1. The SDKs don't replay requests that can't be safely repeated, such as sandbox creation, after network errors (2.52.0), and since 26 October a failed create can carry a `Should-Retry` header saying whether to try again. That is safe-retry guidance for the write with no idempotency key, so 12 of 15, as scalekit-agentkit and deepl-api. No SLA in the billing docs or pricing page (0). GA (10). 20+20+15+12+0+10 = 77.)
- Security & auth, E2B +10: Celesto (formerly SmolVM) 52 (Framework reading for local software. No credential is needed for local use, and the local API server and dashboard each require a bearer token, and cloud keys carry named permissions (22 of 30). Each computer has its own guest kernel, browser and display access uses capability URLs with a read-only option, and raw VNC is off. Against that, outbound networking is open by default and the restricting modes are opt-in (12 of 20). The security doc warns against giving connection URLs to a model as page content, but there is no guidance on treating command or page output as untrusted (5 of 15). `computer logs` shows startup output, with no audit log of commands (5 of 15). SECURITY.md with GitHub private vulnerability reporting and a supported-versions table, Security sections in the changelog, no security.txt, bug bounty or certification (8 of 20). Total 52.); E2B 62 (One plain API key per project in `X-API-Key`. Workload identity tokens give code inside a sandbox short-lived credentials, and personal access tokens were switched off on 1 August 2026. We found no scopes or documented rotation for API keys (20). Each sandbox is a Firecracker microVM with its own kernel (10). Internet access can be switched off or limited with allow and deny lists of domains, IPs and CIDR ranges, GA, though it's on by default (10). Stored secrets are filled into outbound HTTPS headers by the egress proxy, outside the sandbox, but per-host request transforms are in public beta (12). No audit log found for the hosted service (0). security@e2b.dev for reports and a SOC 2 Type II report with a pen-test summary in the trust centre. No security.txt, bug bounty or public advisories found (10).)
- Payments & pricing, Celesto (formerly SmolVM) +10: Celesto (formerly SmolVM) 60 (Read with the self-hosted rule, scoring the hosted option for the price lines. No x402, MPP or L402 (0 of 40). Celesto Cloud publishes hourly prices for six sizes without a login (20). A one-time $5 Micro credit needs no card, and the local SDK is free (20). The graded local SDK installs from PyPI and runs with no account, so an agent needs no signup (20). Cloud use needs a browser signup and a card top-up. Total 60.); E2B 50 (No x402, MPP or L402. A third-party draft pull request (#1910) proposes an `@e2b/x402` package and isn't merged (0). Per-second prices published, $0.000014 a vCPU-second and $0.0000045 a GiB-second (20). A one-time $100 credit on Hobby, and the billing docs ask for a payment method only once it runs out (20). Stripe Projects lists E2B, so an agent can create the account through the operator's Stripe login (10).)
- Schema & documentation, E2B +7: Celesto (formerly SmolVM) 85 (Read as an SDK and CLI. The repository ships an OpenAPI document for the local server (24 operations) and the cloud API (171 operations), from which the TypeScript client is generated (25). llms.txt at celesto.ai, plus Markdown docs in the repository (10). The README's runtime table says when to use each runtime, and the automation section says to prefer `exec` and keep `shell`, `ssh` and `desktop` for interactive work (14 of 20). Network modes are closed values (`open`, `off`, `public`, `restricted`) and the SDK takes typed keyword arguments, though `internet_settings` is a plain dict (11 of 15). Examples directory, a JSON envelope for every command and documented cloud error fields such as `required_scope`, without a full error catalogue (12 of 15). Dated changelog and tags, pre-1.0 (13 of 15). Total 85.); E2B 92 (Public OpenAPI at docs.e2b.dev/openapi-public.yaml, linked from llms.txt (25). llms.txt and Markdown pages (10). The docs explain when to pause rather than kill, how the runtime limit resets on resume, and what a snapshot keeps (15). Typed fields in the spec and SDKs (12). Versioned SDK references with an errors page, and examples on most pages (15). A weekly dated changelog, and v2 sandbox endpoints since 21 September 2026 (15).)