E2B

Status	Tested with a fake server (2026-10-28): implemented from E2B’s published API specs, not run against E2B
Adapter	e2b (internal/adapters/e2b)
Trust	declared (self-hostable): external for E2B’s hosted service; private only for an E2B you operate
Isolation	Firecracker microVM per sandbox
API checked	Control plane: spec/openapi.yml; in-sandbox daemon: spec/envd; docs.e2b.dev, read 2026-10-28

Capabilities

Feature	Supported	Notes
exec	yes	envd process.Process/Start (Connect, JSON) running bash -l -c; separate stdout and stderr; env and cwd native; timeout kills the process (exit 124)
exec.stream	yes	The same call, relayed as it arrives
files	yes	envd GET/POST /files (parent folders created) and ListDir
stdin	yes	Sent with SendInput once the process starts, then closed
lifecycle.stop-start	no	E2B has no stop that keeps the sandbox
lifecycle.pause-resume	yes	Pause keeps memory and disk; a paused sandbox is not billed
snapshots.disk	yes	Captured with memory
snapshots.memory	yes	POST /sandboxes/{id}/snapshots; a snapshot is a template, restored by creating from it
fork	yes	Through a snapshot and a new sandbox from it
ports.expose	with ports: public	https://<port>-<id>.<domain>; every listening port is public
network.egress-control	no	egress: none turns internet access off for the whole pool; E2B’s per-host allow and deny lists are not wired up
max size	8 vCPU, 8 GiB, 20 GiB (plan)	Sizes come from the template; the request’s resources are not applied
provider TTL backstop	yes	timeout (deletes), capped at maxLifetimeSeconds; moved with /timeout

Configure

pools:
  - name: e2b
    adapter: e2b
    trust: external          # required: external for E2B's hosted service
    region: us-west-1
    maxConcurrency: 20       # Hobby allows 20 concurrent sandboxes
    config:
      apiURL: https://api.e2b.app   # default: https://api.<domain>
      domain: e2b.app        # default; other regions have their own domain and key
      template: base         # default template (its size is the sandbox's size)
      maxLifetimeSeconds: "3600"    # the plan's maximum runtime: 3600 Hobby, 86400 Pro
      ports: private         # private (default) or public
      egress: public         # public (default) or none
    credentials: {secret: e2b-key}

differently admin secret put e2b-key --from-file ./e2b-api-key.txt
differently admin pool add e2b --adapter e2b --trust external --region us-west-1 \
  --config maxLifetimeSeconds=3600 --max-concurrency 20 --secret e2b-key

A pool without trust is refused. The Helm chart’s pool schema takes credentials: {env: E2B_API_KEY} with the key in server.extraEnv, or register the pool at runtime as above. A trust: external pool is not placed until policy approves external pools (keys-and-providers.md). The server needs egress to api.<domain> and sandbox.<domain> on 443.

Limits and differences

• Lifetime. E2B deletes a sandbox when its timeout ends, and the plan caps it from each start or resume (1 h Hobby, 24 h Pro). The adapter sends the sandbox’s TTL, never more than maxLifetimeSeconds; a sandbox with no TTL, or a longer one, is deleted at that cap and Differently then reports it gone. Set maxLifetimeSeconds to the plan’s limit: a larger value is refused by E2B at create.
• Sizes. CPU, memory and disk are fixed by the template at build time (the base template has 2 vCPU and 512 MiB). The request’s resources are used for quota and cost only. Build one template per size with E2B’s tools and point pools or templates at them.
• Ports. E2B has no per-port expose. With ports: private (default) the sandbox refuses public traffic and ports.expose is not offered; with ports: public every listening port is reachable by anyone with the URL. This is set at create and cannot change later.
• Snapshots pause the source briefly and drop its open connections, including running commands’ streams. They always include memory.
• Templates and errors. An unknown template is invalid_request, as is one the key may not use (403). 429 and 503 (including sandbox_capacity_unavailable) requeue as insufficient_capacity; sandbox_create_failed is sandbox_failed; 401 and other 5xx are provider_unavailable. Exec against a paused or unreachable sandbox (502 from E2B’s edge) is invalid_state.
• Regions are separate deployments with their own domain and API key (e2b.app is us-west-1). Register one pool per region.
• Quotas: Hobby 20 concurrent sandboxes and 1 create a second; Pro 100 or more and 5 a second. Paused sandboxes do not count.
• Pricing: per second while running, per vCPU and per GiB of RAM; disk is included; paused sandboxes are free.
• E2B’s infrastructure is open source and can be self-hosted. Point apiURL and domain at your install and declare trust: private only if you operate it. The limits above describe E2B’s hosted service; a self-hosted install has not been tried.

How it was tested

go test ./internal/adapters/e2b/ against a fake control plane and a fake envd speaking Connect’s streaming envelopes (2026-10-28): create with template, timeout cap, metadata, env, network and egress settings; idempotent create; exec and streamed exec (cwd, env, exit codes, Connect errors, timeout, stdin through SendInput and CloseStdin); files (write as multipart, read, list, missing paths); pause (twice) and resume with the refreshed envd token; a second adapter fetching the token itself; SetExpiry; snapshot, restore and delete; port URLs and their absence with private ports; paged List with E2B’s metadata filter encoding; idempotent delete; error classification for 401, 403, 404, 429, 500, 503 and E2B’s error codes. Nothing ran against E2B itself: no account or key was available.

---

Source: docs/providers/e2b.md