POST /v1/capsules/{id}/resume — Resume a paused capsule

Use this endpoint to restore a paused capsule from its snapshot. Wrenn boots a fresh Firecracker VM, loads the saved filesystem, and uses userfaultfd (UFFD) for lazy memory page loading so the capsule is ready to accept commands quickly. The capsule resumes exactly where it left off — running processes, in-memory state, and all.

Endpoint

POST https://app.wrenn.dev/api/v1/capsules/{id}/resume

Authentication

Pass your API key in the X-API-Key header.

X-API-Key: wrn_your_key

Path parameters

string

required

The ID of the capsule to resume (e.g., cl-abc123). The capsule must be in paused status.

Response

Returns 200 OK with the updated capsule object. The status field will be "running" once the VM has booted and the internal agent is ready.

string

required

Unique capsule ID, prefixed with cl-.

string

required

Will be "running" after the capsule has fully resumed.

string

required

Name of the template the capsule was created from.

integer

required

Number of virtual CPUs allocated.

integer

required

Memory allocated, in MiB.

integer

required

Inactivity TTL in seconds.

string

required

ISO 8601 timestamp of when the capsule was originally created.

string

required

ISO 8601 timestamp of when the capsule last changed status.

string

ISO 8601 timestamp of when the capsule most recently reached running status.

Example response

{
  "id": "cl-abc123",
  "status": "running",
  "template": "base-python",
  "vcpus": 2,
  "memory_mb": 1024,
  "timeout_sec": 300,
  "created_at": "2024-11-01T10:00:00Z",
  "started_at": "2024-11-01T10:10:02Z",
  "last_active_at": "2024-11-01T10:10:02Z",
  "last_updated": "2024-11-01T10:10:02Z"
}

curl

curl --request POST \
  --url https://app.wrenn.dev/api/v1/capsules/cl-abc123/resume \
  --header 'X-API-Key: wrn_your_key'

Python SDK

The SDK handles resume transparently when you call Capsule.connect() on a paused capsule:

from wrenn import Capsule

# connect() automatically resumes a paused capsule
capsule = Capsule.connect("cl-abc123")
print(capsule.status)  # "running"

You can also resume explicitly on an existing instance:

capsule = Capsule.connect("cl-abc123")
capsule.pause()   # pause it first
capsule.resume()  # resume from the paused state
print(capsule.status)  # "running"

Error responses

Status	Description
`401 Unauthorized`	Missing or invalid `X-API-Key`.
`404 Not Found`	No capsule with the given ID exists in your team.
`409 Conflict`	The capsule is not in `paused` status. Only paused capsules can be resumed.

Capsules

Execution

Files

Snapshots

POST /v1/capsules/{id}/resume — Resume a paused capsule

Endpoint

Authentication

Path parameters

Response

Example response

curl

Python SDK

Error responses

​Endpoint

​Authentication

​Path parameters

​Response

​Example response

​curl

​Python SDK

​Error responses

Endpoint

Authentication

Path parameters

Response

Example response

curl

Python SDK

Error responses