Blaxel

Status	Tested with a fake server (implemented from Blaxel’s published OpenAPI specs, not run against Blaxel)
Adapter	blaxel (internal/adapters/blaxel)
Trust	external (provider-managed; Blaxel is hosted-only)
Isolation	microVM per sandbox, Blaxel-managed. The docs say “microVMs” without naming the hypervisor; Blaxel’s blog says Firecracker
API checked	Control plane: controlplane.yml. In-sandbox API: sandbox-api openapi.yml. Guides at docs.blaxel.ai. All read 2026-10-28

Blaxel splits its API in two. The control plane (api.blaxel.ai/v0) creates, lists and deletes sandboxes. Each sandbox then serves its own API at its metadata.url (https://sbx-<name>-<workspace>.<region>.bl.run), which runs commands and moves files. The adapter uses both, with one API key.

Capabilities

Capability	Support
exec	yes; runs through sh -c in the sandbox with env, cwd and timeoutSeconds (Blaxel kills the process at the deadline). The adapter reads Blaxel’s NDJSON stream, so commands may outlast the 60 s cap on Blaxel’s waiting form
exec.stream	yes; chunks as the process writes them. A command that finishes before Blaxel streams anything arrives one line per event without the newline; buffered exec uses the final result and is exact
files	yes; read, write (parent directory created first) and one-level list. On mk3.0 sandboxes Blaxel’s proxy refuses bodies over 8 MiB, reported as invalid_request
stdin	yes; staged in a temporary file the command reads, then removed. Not interactive
lifecycle.stop-start	no; Blaxel has no stop or start call
lifecycle.pause-resume	no explicit call. Blaxel puts a sandbox with no connection into standby on its own after about 15 s, keeping memory and processes, and wakes it on the next request in under 25 ms; standby compute is not billed
snapshots.disk	no; Blaxel’s snapshots are a private preview, marked WIP in its spec
snapshots.memory	no (same private preview)
fork	no (same private preview)
ports.expose	yes: a private preview URL with a preview token valid for one hour in its query string (?bl_preview_token=…); anyone holding the URL can reach the port until the token expires
network.egress-control	no; Blaxel’s spec has network settings, but the adapter doesn’t set them
Max size	tier-dependent, shown only in Blaxel’s console. CPU follows memory (one core per 2048 MB); the root filesystem lives in memory, so diskGiB has no effect
Provider TTL backstop	spec.runtime.ttl, set to the sandbox’s TTL and at least 5 minutes (Blaxel’s minimum); not moved when the TTL changes later

Configure

Key	Default	Meaning
workspace	required	The Blaxel workspace name, sent as X-Blaxel-Workspace
region	Blaxel picks the closest	us-pdx-1, us-was-1, eu-lon-1 or eu-fra-1 (what your account can use)
image	blaxel/base-image:latest	A Blaxel hub image or a template image from your workspace. A request’s template overrides it
apiURL	https://api.blaxel.ai/v0	The control plane

The credential is a Blaxel API key (Console → Profile → Security, or a service account’s key, which reaches only its own workspace).

differently admin secret put blaxel-key --from-file ./blaxel-api-key.txt
differently admin pool add blaxel --adapter blaxel --trust external \
  --config workspace=my-workspace --config region=us-pdx-1 \
  --region us-pdx-1 --max-concurrency 10 --secret blaxel-key

In the server config file:

pools:
  - name: blaxel
    adapter: blaxel
    trust: external          # always external; a private claim is overridden
    region: us-pdx-1
    maxConcurrency: 10
    config:
      workspace: my-workspace
      region: us-pdx-1
    credentials: {secret: blaxel-key}

With Helm, the chart’s providers.* block covers Daytona and Freestyle only. Either register the pool at runtime as above, or add it under config.pools with credentials: {env: DIFFERENTLY_BLAXEL_API_KEY} and set that variable through server.extraEnv from a Kubernetes Secret. In both cases set networkPolicy.server.egress.runtimeProviders: true, so the server can reach api.blaxel.ai and the sandboxes’ *.bl.run hosts on port 443.

Like every external pool, it receives no work until the global policy approves it (keys and providers).

Limits and differences

• Idempotent create uses Blaxel’s createIfNotExist=true with a name derived from the sandbox ID (sbx_01ABC → sbx-01abc); names are unique per workspace.
• Listing pages through every sandbox in the workspace and filters on the adapter’s labels (dly-sandbox, dly-installation), because Blaxel’s only server-side search is fuzzy. A large shared workspace makes each reconcile pass slower; a workspace per installation keeps it small.
• Error classification: 429 and QUOTA_EXCEEDED → insufficient_capacity; 400 INVALID_IMAGE → invalid_request; 408 CREATION_TIMEOUT and a sandbox Blaxel reports FAILED → sandbox_failed; 5xx and rejected credentials → provider_unavailable. A create that times out at Blaxel’s edge (504) is followed by name until it is ready.
• Idle timeouts: Differently’s idleTimeoutSeconds leaves Blaxel sandboxes alone, since the pool can neither pause nor stop them. Blaxel’s own standby already stops compute billing when a sandbox is idle.
• Restore from a snapshot is refused with unsupported_operation.
• Sandbox count is capped per tier (10 on the free tier, 50 and 200 on the next two), and TTLs are capped at 7 days on the free tier.
• Pricing: active compute is billed per GB of memory per second, CPU included; standby compute is free.
• Sandbox environment variables are stored in the sandbox’s spec on Blaxel.

How it was tested

Unit tests in internal/adapters/blaxel run against a fake server built from the published control-plane and sandbox API shapes: create (including a replayed create and a 504 at the edge), get, paged list filtered by installation, a list page that fails, delete twice, exec (exit codes, env, cwd, timeout, staged stdin, a command that cannot start), the NDJSON stream, file read, write and list, preview URLs, and error classification for 401, 408, 429, QUOTA_EXCEEDED, INVALID_IMAGE and 503. Run on 2026-10-28 with go test -race.

Not run: anything against a live Blaxel account. Unconfirmed from the docs: whether the sandbox API needs X-Blaxel-Workspace (the adapter sends it), and the exact error bodies Blaxel returns at its gateway.

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Source: docs/providers/blaxel.md