> ## Documentation Index > Fetch the complete documentation index at: https://orbit.nckrtl.com/docs/llms.txt > Use this file to discover all available pages before exploring further. # Register a T3 server > Called from a T3 server's host on startup with an admin session from `t3 auth session issue --label "Orbit Gateway"`. The Gateway checks that `url` serves `environment_id` and that T3 accepts `admin_session` with admin scopes, stores the session encrypted, and revokes its earlier sessions on that server. Returns `conn.environment_mismatch` or `conn.admin_scope_missing` (422), and `conn.server_unreachable`, `conn.session_rejected`, `conn.request_refused`, or `conn.response_invalid` (502). ## OpenAPI ````yaml /openapi.json post /api/v1/conn/environments openapi: 3.1.0 info: title: Orbit Gateway API version: v1 description: >- The HTTP API of the active Orbit Gateway. The CLI and the PHP SDK send every fleet command through these endpoints over WireGuard. See [Using the API](/api/overview) for transport, authentication, envelopes, and errors. servers: - url: https://gateway.orbit description: >- The active Gateway on the private WireGuard network, resolved by Orbit private DNS. security: [] tags: - name: Gateway description: >- Status and trust of the active Gateway, and the releases of the Gateway itself. - name: Nodes description: Machines in the fleet, their roles, access grants, and storage settings. - name: Clusters description: Groups of Nodes with one Router and one development TLD. - name: Firewall description: Named UFW rules on one Node. - name: Fleet rollout description: >- The rollout of each verified Gateway release to the managed Nodes, and its catch-up. - name: Tools description: Packages that Orbit installs on a Node through a Tool Manager. - name: Metrics description: The Prometheus and Grafana role and its exporters. - name: GitHub App description: The Gateway's own read-only GitHub App and the accounts that installed it. - name: Analytics description: >- The analytics role, its Plausible version, and the Stats API key the Gateway uses to read visits. - name: Projects description: Repository records with one type, default branch, and web root each. - name: Instances description: Development checkouts and production releases of a Project on one Node. - name: Environment description: Stored Instance environment configuration and its .env projection. - name: Routes description: Domains that reach an Instance. - name: Database connections description: The registry of mysql, pgsql, and sqlite connections. - name: Processes description: >- systemd services and Docker containers owned by an Instance, a Node, or a Project definition. - name: Schedules description: Recurring commands run by native systemd timers. - name: Annotations description: Instance annotations, T3 delivery, and replayable status events. - name: Tasks description: Commander feature groups and ordered subtasks. - name: Extensions description: Gateway-owned extension switches. - name: Doctor description: Verify-only drift checks across the fleet. - name: Activities description: The Gateway log of authorized commands. - name: proxycli description: CLIProxyAPI quota snapshots, provider pools, and account controls. - name: Vaultwarden description: The copy of database credentials into a Vaultwarden collection. - name: Conn description: >- Profiles, shared workspace settings, registered T3 servers, and the pairing links the Gateway mints on them for each Node. - name: Realtime description: >- The record-change event feed broadcast to Reverb, its channel authorization, and Reverb connection discovery. - name: Node callbacks description: Endpoints that managed Nodes and Caddy call; operators do not call them. paths: /api/v1/conn/environments: post: tags: - Conn summary: Register a T3 server description: >- Called from a T3 server's host on startup with an admin session from `t3 auth session issue --label "Orbit Gateway"`. The Gateway checks that `url` serves `environment_id` and that T3 accepts `admin_session` with admin scopes, stores the session encrypted, and revokes its earlier sessions on that server. Returns `conn.environment_mismatch` or `conn.admin_scope_missing` (422), and `conn.server_unreachable`, `conn.session_rejected`, `conn.request_refused`, or `conn.response_invalid` (502). operationId: conn-environment-register requestBody: required: true content: application/json: schema: type: object properties: environment_id: type: string pattern: ^\S+$(?![\s\S]) maxLength: 255 label: type: string maxLength: 255 url: type: string format: uri maxLength: 2048 admin_session: type: string pattern: ^\S+$(?![\s\S]) maxLength: 4096 required: - environment_id - label - url - admin_session additionalProperties: false responses: '200': description: The request succeeded. content: application/json: schema: type: object properties: data: $ref: '#/components/schemas/ConnEnvironment' meta: $ref: '#/components/schemas/Meta' required: - data - meta '403': description: >- The caller is not an active WireGuard peer (`peer.identity_unknown`) or lacks Node access to the target (`node_access.required`). content: application/json: schema: $ref: '#/components/schemas/Error' '409': description: >- A guard refused the change and the Gateway changed nothing; `error.code` names the guard. content: application/json: schema: $ref: '#/components/schemas/Error' '422': description: >- The JSON body is not an object, has duplicate or unknown members, or fails validation (`validation.failed`). content: application/json: schema: $ref: '#/components/schemas/Error' x-codeSamples: - lang: bash label: curl source: | curl -sS -X POST "https://gateway.orbit/api/v1/conn/environments" \ --cacert /path/to/orbit-root-ca.pem \ -H 'Accept: application/json' \ -H 'X-Orbit-Request-Id: 9d6b1e5c-4a3f-4a1b-9f0e-6d2c3f5a7b81' \ -H 'Content-Type: application/json' \ -d '{"environment_id": "example", "label": "example", "url": "example", "admin_session": "example"}' components: schemas: ConnEnvironment: type: object properties: environment_id: type: string label: type: string url: type: string server_version: type: - string - 'null' registered_by: type: - string - 'null' registered_at: type: string admin_session_expires_at: type: string status: type: string Meta: type: object properties: request_id: type: string format: uuid description: >- The request ID the Gateway assigned or accepted; the same value is in the `X-Orbit-Request-Id` response header and in the Activity record. required: - request_id Error: type: object properties: error: type: object properties: code: type: string description: >- Stable error code, namespaced by family, such as `node.not_active` or `route.target_conflict`. message: type: string description: >- Safe message without credentials, environment values, or remote output. details: type: object additionalProperties: true description: >- Bounded, redacted details such as the conflicting record IDs or the failed validation rule. request_id: type: string format: uuid required: - code - message required: - error ```` This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.