---
title: Create Tunnel Certificate
url: https://platform.claude.com/docs/en/api/ruby/beta/tunnels/certificates/create
---

# Create Tunnel Certificate

`beta.tunnels.certificates.create(tunnel_id, **kwargs) -> BetaTunnelCertificate`

**POST** `/v1/tunnels/{tunnel_id}/certificates`

The Tunnels API is in research preview. It requires the `anthropic-beta: mcp-tunnels-2026-06-22` header and may change without a deprecation period. It supersedes the Admin API endpoints at `/v1/organizations/tunnels`, which remain available during a migration window.

Registers a public CA certificate on a tunnel. Anthropic verifies the gateway's server certificate against this CA when it terminates the inner TLS session. A tunnel holds at most two non-archived certificates.

## Parameters

- `tunnel_id: String` (path parameter)

  ID of the tunnel (`tnl_...`).

- `ca_certificate_pem: String`

  PEM-encoded X.509 CA certificate. Must contain exactly one certificate and no private-key material. Maximum 8KB.

  maxLength: 8192

- `betas: Array[AnthropicBeta]` (header parameter)

  This endpoint is in beta: requests must send `mcp-tunnels-2026-06-22` in this header.

  - `String = String`

  - `:"message-batches-2024-09-24"`

  - `:"prompt-caching-2024-07-31"`

  - `:"computer-use-2024-10-22"`

  - `:"computer-use-2025-01-24"`

  - `:"pdfs-2024-09-25"`

  - `:"token-counting-2024-11-01"`

  - `:"token-efficient-tools-2025-02-19"`

  - `:"output-128k-2025-02-19"`

  - `:"files-api-2025-04-14"`

  - `:"mcp-client-2025-04-04"`

  - `:"mcp-client-2025-11-20"`

  - `:"dev-full-thinking-2025-05-14"`

  - `:"interleaved-thinking-2025-05-14"`

  - `:"code-execution-2025-05-22"`

  - `:"extended-cache-ttl-2025-04-11"`

  - `:"context-1m-2025-08-07"`

  - `:"context-management-2025-06-27"`

  - `:"model-context-window-exceeded-2025-08-26"`

  - `:"skills-2025-10-02"`

  - `:"fast-mode-2026-02-01"`

  - `:"output-300k-2026-03-24"`

  - `:"user-profiles-2026-03-24"`

  - `:"user-profiles-2026-08-18"`

  - `:"user-profiles-2026-09-04"`

  - `:"advisor-tool-2026-03-01"`

  - `:"managed-agents-2026-04-01"`

  - `:"cache-diagnosis-2026-04-07"`

  - `:"dreaming-2026-04-21"`

  - `:"thinking-token-count-2026-05-13"`

  - `:"server-side-fallback-2026-06-01"`

  - `:"server-side-fallback-2026-07-01"`

  - `:"fallback-credit-2026-06-01"`

  - `:"fallback-credit-2026-07-01"`

  - `:"agent-memory-2026-07-22"`

  - `:"mid-conversation-tool-changes-2026-07-01"`

  - `:"compact-2026-01-12"`

  - `:"computer-use-2025-11-24"`

  - `:"mcp-tunnels-2026-06-22"`

  - `:"structured-outputs-2025-11-13"`

  - `:"task-budgets-2026-03-13"`

  - `:"thinking-display-updates-2026-08-18"`

  - `:"ce-user-management-2026-07-13"`

  - `:"mid-conversation-output-config-2026-07-01"`

  - `:"thinking-binding-controls-2026-08-01"`

  - `:"mid-conversation-system-clear-at-2026-08-21"`

  - `:"compact-2026-09-04"`

  - `:"inline-tools-2026-09-15"`

  - `:"mcp-client-2026-09-15"`

  - `:"ce-plugins-2026-09-01"`

  - `:"spend-limit-reads-2026-09-26"`

  - `:"telemetry-destinations-2026-08-11"`

- `workspace_id: String` (header parameter)

  Optional header to select the Workspace for this request. The value is a Workspace ID (for example, `wrkspc_011CZkZaBF1tNoB5wlCeusgy`).

  Only needed for credentials that can act on more than one Workspace. A credential that belongs to a specific Workspace may omit it; if sent, it must match that Workspace.

## Returns

- `class BetaTunnelCertificate`

  A CA certificate attached to a tunnel.

  - `type: :tunnel_certificate`

  - `id: String`

    Unique identifier for the certificate, prefixed with `tcrt_`.

  - `archived_at: Time`

    RFC 3339 datetime string indicating when the certificate was archived. Null if it is still in the trusted set.

    format: date-time

  - `created_at: Time`

    RFC 3339 datetime string indicating when the certificate was registered.

    format: date-time

  - `expires_at: Time`

    RFC 3339 datetime string indicating when the certificate expires, or `null` if it does not expire.

    format: date-time

  - `fingerprint: String`

    Lowercase hex SHA-256 fingerprint of the certificate's DER encoding.

  - `tunnel_id: String`

    ID of the tunnel the certificate is registered against.

## Example

```ruby
require "anthropic"

anthropic = Anthropic::Client.new(api_key: "my-anthropic-api-key")

beta_tunnel_certificate = anthropic.beta.tunnels.certificates.create("tunnel_id", ca_certificate_pem: "ca_certificate_pem")

puts(beta_tunnel_certificate)
```

### Response (200)

```json
{
  "id": "id",
  "archived_at": "2019-12-27T18:11:19.117Z",
  "created_at": "2019-12-27T18:11:19.117Z",
  "expires_at": "2019-12-27T18:11:19.117Z",
  "fingerprint": "fingerprint",
  "tunnel_id": "tunnel_id",
  "type": "tunnel_certificate"
}
```