> ## Documentation Index > Fetch the complete documentation index at: https://docs.sailresearch.com/llms.txt > Use this file to discover all available pages before exploring further. # Create a Sailbox > Creates a Sailbox and waits for startup to finish, which can take a few minutes. `image` has to describe an image that is ready to boot: a base image on its own, or one already built from that same spec through an SDK or the CLI. Send an `Idempotency-Key` so a network retry replays this answer instead of starting a second Sailbox. A server error can still arrive once the Sailbox exists, so read [Retrying safely](/sailboxes-http-api#retrying-safely) before you retry one. ## OpenAPI ````yaml /sailbox-openapi.json post /sailboxes openapi: 3.1.0 info: title: Sail Sailbox API version: '2026-07-26' description: >- Create and operate Sailboxes over HTTP. Sailboxes are fast-booting virtual machines that you can pause, resume, checkpoint, and fork. Three things need an SDK or the CLI: running commands and moving files, turning on SSH, and building an image. Once SSH is on you can use `ssh` and `scp` for the first of those. See the [HTTP API guide](/sailboxes-http-api). servers: - url: https://sailbox-api.sailresearch.com/v1 security: - BearerAuth: [] tags: - name: Apps description: Groups that own Sailboxes. One app per workload. - name: Lifecycle description: >- A Sailbox's whole life: create it, watch it, stop and start it, terminate it. - name: Checkpoints description: Save a Sailbox to start from later, and copy a running one. - name: Networking description: >- Publish ports, serve them on hostnames you own, and identify a Sailbox to other Sailboxes. - name: Volumes description: >- Shared storage that outlives any one Sailbox. Alpha: these endpoints can still change. - name: SSH access description: Certificates for connecting to a Sailbox with `ssh`. - name: Usage description: Resource usage and spend. - name: Identity description: Who your API key belongs to. paths: /sailboxes: post: tags: - Lifecycle summary: Create a Sailbox description: >- Creates a Sailbox and waits for startup to finish, which can take a few minutes. `image` has to describe an image that is ready to boot: a base image on its own, or one already built from that same spec through an SDK or the CLI. Send an `Idempotency-Key` so a network retry replays this answer instead of starting a second Sailbox. A server error can still arrive once the Sailbox exists, so read [Retrying safely](/sailboxes-http-api#retrying-safely) before you retry one. operationId: createSailbox parameters: - $ref: '#/components/parameters/IdempotencyKey' requestBody: required: true content: application/json: schema: $ref: '#/components/schemas/CreateSailboxRequest' example: name: worker-1 app_id: app_0f6a2c31-8b4d-4e7a-9c15-2d8e6f4a1b03 size: m image: base: BASE_IMAGE_DEBIAN ingress_ports: - guest_port: 8000 protocol: http allowlist: - 203.0.113.0/24 responses: '200': description: >- Check `status`: `running` means the Sailbox is ready, and `failed` means it did not start, with `error_message` saying why. content: application/json: schema: $ref: '#/components/schemas/CreatedSailbox' example: sailbox_id: sb_9c8f1e2a-3b4d-4f5a-8c7e-1d2f3a4b5c6d status: running headers: Idempotent-Replayed: $ref: '#/components/headers/IdempotentReplayed' '400': description: >- The request was rejected. See the error message for the offending field. content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' example: error: message: memory_gib for size m must be between 8 and 128 type: invalid_request_error param: null code: null headers: Idempotent-Replayed: $ref: '#/components/headers/IdempotentReplayed' '401': description: The API key is missing or invalid. content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' example: error: message: Invalid API key type: authentication_error param: null code: invalid_api_key '402': description: >- The organization is out of credits. The error carries a `billing_url` pointing at the page where you add them. Retry once you have. content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' example: error: message: >- Your API key has been disabled due to insufficient credits. Visit https://app.sailresearch.com/billing to add credits. type: billing_error param: null code: credits_exhausted billing_url: https://app.sailresearch.com/billing '403': description: The API key is not allowed to perform this operation. content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' example: error: message: sailboxes require an organization-scoped API key type: permission_error param: null code: null '404': description: >- No app with that `app_id` exists in your organization, or a volume named in `volume_mounts` does not. content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' example: error: message: sailbox "sb_9c8f1e2a-3b4d-4f5a-8c7e-1d2f3a4b5c6d" not found type: not_found_error param: null code: null headers: Idempotent-Replayed: $ref: '#/components/headers/IdempotentReplayed' '409': description: >- The request cannot be served as written: `image` names an image that has not been built, `visibility` is `private` on a key that carries no user, or a requested `tcp` port is not available. An `Idempotency-Key` reused for a different request lands here too. content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' example: error: message: idempotency key reused with a different request body type: conflict_error param: null code: null headers: Idempotent-Replayed: $ref: '#/components/headers/IdempotentReplayed' '413': description: The request body is larger than the 256 MiB this endpoint accepts. content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' example: error: message: request body too large type: invalid_request_error param: null code: null '429': description: >- Too many requests in flight, or the organization is at a limit. A `Retry-After` header means the request never started, so retry it unchanged after that delay. Without one, the request ran and hit the limit `message` names. Some of those clear on their own, such as a shortage of public ports; others need you to free something up first. Send the request again once the cause is gone. If you sent an `Idempotency-Key`, use a new one, because the old key now replays this answer. content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' example: error: message: >- Too many concurrent requests. Please retry after some of your organization's in-flight requests complete. type: rate_limit_error param: null code: rate_limited headers: Retry-After: $ref: '#/components/headers/RetryAfter' Idempotent-Replayed: $ref: '#/components/headers/IdempotentReplayed' '500': description: Server error. content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' example: error: message: failed to fetch sailbox type: server_error param: null code: null '503': description: >- Sail is momentarily unavailable. Retry after the delay in the `Retry-After` header when one is present, and with backoff otherwise. content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' example: error: message: Authentication service unavailable type: server_error param: null code: null headers: Retry-After: $ref: '#/components/headers/RetryAfter' '504': description: >- The operation outran its deadline, or a retry sent with the same `Idempotency-Key` waited about 30 seconds and the original request was still going. The new Sailbox can exist even though the call failed, so list your Sailboxes before you retry. content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' example: error: message: idempotent request still in flight type: server_error param: null code: null components: parameters: IdempotencyKey: name: Idempotency-Key in: header required: false schema: type: string maxLength: 255 description: >- Makes the request retry-safe. Sail remembers the answer it sent under a key, including a 400 or a 409, and replays it with `Idempotent-Replayed: true` for a retry that repeats the key, the method, the path, and the body. Bodies are compared byte for byte. Reusing a key for a different request returns 409, so send a corrected request under a new key. A key that is blank or only spaces is ignored, and the request runs without idempotency. Any string of up to 255 bytes works, and characters outside ASCII count for more than one. A UUID is a good default. Keys are remembered for at least 24 hours and scoped to the API key that sent them. A server error, or a failure to record the answer, can leave a key unsettled, and creating a Sailbox is where that matters. See [Retrying safely](/sailboxes-http-api#retrying-safely). schemas: CreateSailboxRequest: type: object required: - name - app_id - image properties: name: type: string minLength: 1 pattern: \S maxLength: 128 description: >- Human-readable name for the new Sailbox. Names are not unique, so keep hold of the returned `sailbox_id`. It is stored as you send it, surrounding spaces included, so trim it yourself if you compare names later. Control characters are not allowed. app_id: type: string minLength: 1 pattern: \S description: >- Id of the app that will own the Sailbox. Use `POST /apps/find` to look one up by name. image: $ref: '#/components/schemas/ImageSpec' size: type: string enum: - s - m - l - '' default: m description: Machine size. `s` is 1 vCPU, `m` is 4 vCPUs, `l` is 8 vCPUs. memory_limit_gib: type: integer description: >- Memory limit in GiB. Allowed ranges are 2 to 64 for size `s`, 8 to 128 for `m`, and 16 to 256 for `l`. Omit it to take the default for the size: 16 for `s`, 32 for `m`, and 64 for `l`. state_disk_limit_gib: type: integer description: >- Disk limit in GiB. Allowed ranges are 8 to 128 for size `s`, 32 to 512 for `m`, and 64 to 1024 for `l`. Omit it to take the default for the size: 32 for `s`, 128 for `m`, and 256 for `l`. ingress_ports: type: array items: $ref: '#/components/schemas/IngressPort' description: >- Ports to publish. You can also publish ports later without restarting. volume_mounts: type: array items: $ref: '#/components/schemas/VolumeMount' description: Volumes to mount into the Sailbox. visibility: type: string enum: - org - private - '' default: org description: >- `org` lets anyone in your organization operate the Sailbox. `private` restricts that to the user whose key created it, so it needs a user-scoped key. An organization admin can still pause, resume, sleep, schedule a wake, upgrade, or terminate it by sending `X-Sail-Owner-Override-Reason`. allOf: - if: required: - size properties: size: const: s then: properties: memory_limit_gib: anyOf: - const: 0 - minimum: 2 maximum: 64 state_disk_limit_gib: anyOf: - const: 0 - minimum: 8 maximum: 128 - if: anyOf: - required: - size properties: size: enum: - m - '' - not: required: - size then: properties: memory_limit_gib: anyOf: - const: 0 - minimum: 8 maximum: 128 state_disk_limit_gib: anyOf: - const: 0 - minimum: 32 maximum: 512 - if: required: - size properties: size: const: l then: properties: memory_limit_gib: anyOf: - const: 0 - minimum: 16 maximum: 256 state_disk_limit_gib: anyOf: - const: 0 - minimum: 64 maximum: 1024 CreatedSailbox: type: object properties: sailbox_id: type: string description: Id of the new Sailbox. status: type: string description: >- Current state of the Sailbox. Values in use today are `creating`, `running`, `paused`, `sleeping`, `terminating`, `terminated`, `failed`, `create_failed`, `interrupted_restorable`, and `interrupted_unsafe_to_retry`. New values can appear over time, so treat this as an open set. error_message: type: string description: Why the Sailbox failed to start, when it did. required: - sailbox_id - status ErrorResponse: type: object required: - error properties: error: $ref: '#/components/schemas/ErrorObject' ImageSpec: type: object additionalProperties: false description: >- Describes the environment the Sailbox boots into. A base image on its own is ready to boot. Adding build steps, environment variables, or a Python version describes an image that has to be built before a Sailbox can start from it, and building one takes an SDK or the CLI. required: - base properties: base: type: string enum: - BASE_IMAGE_DEBIAN - BASE_IMAGE_DEVBOX description: >- Starting point for the image. `BASE_IMAGE_DEBIAN` is a plain Debian base you can build on. `BASE_IMAGE_DEVBOX` is a prebuilt development environment that accepts no build steps, environment variables, or Python version. build_steps: type: array items: $ref: '#/components/schemas/ImageBuildStep' description: Steps applied to the base image, in order. env: type: object propertyNames: pattern: ^[A-Za-z_][A-Za-z0-9_]*$ additionalProperties: type: string description: >- Environment variables baked into the image and present in every process. A variable name must start with a letter or `_` and contain only letters, numbers, and `_`. architecture: type: string enum: - IMAGE_ARCHITECTURE_AMD64 - IMAGE_ARCHITECTURE_ARM64 description: >- CPU architecture to build for. Defaults to `IMAGE_ARCHITECTURE_AMD64`. python_version: type: string pattern: ^([0-9]+\.[0-9]+\.[0-9]+)?$ description: >- Python version to install as `python3`. Give the full patch version, such as `3.12.13`; `3.12` is rejected. examples: - 3.12.13 allOf: - if: required: - base properties: base: const: BASE_IMAGE_DEVBOX then: properties: build_steps: maxItems: 0 env: maxProperties: 0 python_version: maxLength: 0 IngressPort: type: object required: - guest_port properties: guest_port: type: integer minimum: 1 maximum: 65535 description: >- Port your process listens on inside the Sailbox. Ports 10000, 10001, 15001, and 15002 are reserved and cannot be published on either protocol. Port 22 is reserved on `http` and available on `tcp`, which is what SSH needs. A guest port is published under one protocol at a time. Publishing it again under that same protocol replaces its allowlist; publishing it under the other protocol is refused. protocol: type: string enum: - http - tcp - '' default: http description: >- `http` publishes an HTTPS URL. `tcp` publishes a host and port for raw TCP, which is what SSH and database clients need. allowlist: type: array items: type: string description: >- Restricts who can reach the listener. An address or a range, such as `203.0.113.0/24`, lets matching source IPs in, and works on both protocols. An app name, which lets Sailboxes in that app call this one, works on `http` only and is rejected on `tcp`. An app name must not look like an address or a range, and must not contain a `/`. Every entry that reads as an address or a range is taken as one, and any other entry holding a `/` is refused as a malformed range. An address must not carry an IPv6 zone, such as `fe80::1%eth0`, which names an interface on one machine rather than a source. Entries come back canonicalized: a range is reported by its network address, a bare address as a single-address range, and blank or repeated entries are dropped. Leaving it empty makes the listener reachable by anyone who has the address. That is refused on a `tcp` listener for a well-known unauthenticated service port such as 5432 or 6379: publish those with an explicit allowlist, using `0.0.0.0/0` and `::/0` if you do want the whole internet. VolumeMount: type: object required: - volume_id - mount_path properties: volume_id: type: string minLength: 1 pattern: \S description: Id of a volume you created earlier. mount_path: type: string pattern: ^\s*/. description: >- Absolute path inside the Sailbox where the volume appears. Repeated slashes and `.`/`..` segments are resolved first, and the result cannot be `/`. Two mounts in one request cannot nest inside each other. examples: - /mnt/shared ErrorObject: type: object required: - message - type - param - code properties: message: type: string description: Human-readable description of what went wrong. type: type: string description: >- Error category: `invalid_request_error`, `authentication_error`, `permission_error`, `billing_error`, `not_found_error`, `conflict_error`, `rate_limit_error`, or `server_error`. param: oneOf: - type: string - type: 'null' description: >- The request field the error refers to, when the error is about one field. code: oneOf: - type: string - type: integer - type: 'null' description: Stable short code for the error, when one applies. billing_url: type: string format: uri description: Page where you add credits. Sent with a 402. additionalProperties: true ImageBuildStep: type: object additionalProperties: false description: One build step. Set exactly one field per step. Steps run in order. minProperties: 1 maxProperties: 1 properties: apt_install: $ref: '#/components/schemas/PackageInstall' pip_install: $ref: '#/components/schemas/PackageInstall' run_command: type: object additionalProperties: false required: - command properties: command: type: string minLength: 1 pattern: \S description: Shell command to run while building the image. add_local_file: $ref: '#/components/schemas/AddLocalFile' add_local_dir: $ref: '#/components/schemas/AddLocalDir' PackageInstall: type: object additionalProperties: false required: - packages properties: packages: type: array minItems: 1 items: type: string minLength: 1 pattern: \S description: Package names to install. AddLocalFile: type: object additionalProperties: false description: >- Copies one file into the image. Its contents are uploaded while the image is built. required: - content_sha256 - remote_path properties: content_sha256: type: string pattern: ^[0-9a-f]{64}$ description: SHA-256 of the file contents, lowercase hex. remote_path: type: string pattern: ^/ description: >- Absolute path the file lands on inside the image. No trailing `/` and no `..` segment. A space, `$`, `"`, or `\` anywhere in the path is rejected. examples: - /opt/app/entrypoint.sh mode: type: integer minimum: 0 maximum: 511 description: >- Permission bits for the file, as a number. `493` is `rwxr-xr-x`. Omit it, or send `0`, for `420` (`rw-r--r--`). AddLocalDir: type: object additionalProperties: false description: >- Copies a directory of files into the image. Their contents are uploaded while the image is built. required: - remote_path - files properties: remote_path: type: string pattern: ^/ description: >- Absolute directory the files land in inside the image. It cannot be `/`. No trailing `/` and no `..` segment. A space, `$`, `"`, or `\` anywhere in the path is rejected. examples: - /opt/app files: type: array minItems: 1 maxItems: 50000 items: $ref: '#/components/schemas/AddLocalDirFile' description: The files to copy. Every `relative_path` has to be distinct. AddLocalDirFile: type: object additionalProperties: false description: One file within an `add_local_dir` step. required: - relative_path - content_sha256 properties: relative_path: type: string maxLength: 1024 pattern: ^[^/] description: >- Path within the directory, relative to `remote_path`. No leading or trailing `/`, and no empty, `.`, or `..` segment. A `$`, `"`, or `\` anywhere in the path is rejected. The limit is 1024 bytes, and characters outside ASCII count for more than one. examples: - src/main.py content_sha256: type: string pattern: ^[0-9a-f]{64}$ description: SHA-256 of the file contents, lowercase hex. mode: type: integer minimum: 0 maximum: 511 description: >- Permission bits for the file, as a number. `493` is `rwxr-xr-x`. Omit it, or send `0`, for `420` (`rw-r--r--`). headers: IdempotentReplayed: description: >- `true` when this response is the stored answer to an earlier request that sent the same `Idempotency-Key`. Absent when the request ran for the first time. schema: type: string enum: - 'true' RetryAfter: description: >- How many seconds to wait before retrying. On a 429 it also means the request never started, so the retry can reuse the same `Idempotency-Key`. schema: type: integer minimum: 0 securitySchemes: BearerAuth: type: http scheme: bearer bearerFormat: API Key ````