Read and decide the requests for approval

An approval is a request for a person's decision that an execution waits on. A Require Approval node raises one, and so does an AI Model node whose overrun policy asks a person. The operations of this page list the requests and decide one. The console shows the same requests on Approvals.

Who reads and who decides

Reading the requests takes management:read. Deciding one takes management:write, because a decision lets an execution spend money. The audit log records every decision.

A key reads and decides the requests of its own project. A request of another project, or one that does not exist, answers 404 with the code approval_not_found.

The list is the newest first and is read page by page, as Requests describes. Send status=pending to read only the requests that still wait.

What a decision does

• The body is optional. Its reason, of up to 500 characters, is kept with the approval and shows in the trace of the execution.

• The answer is the approval with its new status and decided_at. A decision made with an API key names the key in decided_by. A decision made in the console names the person in decided_by_user_id and decided_by_name.

• The request does not move the execution. The execution goes on within a minute: through the Approved port after an approval, and through Rejected after a rejection.

• A request from a model node is decided the same way. An approval lets the model call go on with a new hold, and a rejection refuses it with overrun_stopped — Approvals says what follows.

• Slen sends the webhook event approval.decided with the verdict.

A request that can no longer be decided

A request waits until expires_at. The author of a Require Approval node sets the time on the node, and a request from a model node waits 24 hours. When nobody decides in time, the request becomes expired within a minute, and approval.decided says expired. From then on it goes as after a rejection: the execution leaves a Require Approval node through Rejected, and the call of a model node is refused with overrun_stopped.

• A request that is no longer pending answers 409 with the code approval_already_decided: somebody decided it, or it has expired.

• A request that is still pending when its time has passed answers 409 with the code approval_expired. It is closed as expired at once, as if nobody had decided, and the execution goes on as after a rejection.

• A request whose execution has ended and no longer waits answers the same approval_expired. It is closed as expired, nothing goes on, and no webhook event is sent.

Operations

{
  "data": [
    {
      "approval_id": "74438200973594624",
      "project_id": "74438200973594624",
      "execution_id": "74438200973594624",
      "flow_id": "74438200973594624",
      "node_key": "string",
      "operation_code": "generate_email",
      "note": "string",
      "status": "pending",
      "decided_by": "string",
      "decided_by_user_id": "74438200973594624",
      "decided_by_name": "string",
      "reason": "string",
      "expires_at": "2026-10-02T09:30:00Z",
      "created_at": "2026-10-02T09:30:00Z",
      "decided_at": "2026-10-02T09:30:00Z"
    }
  ],
  "meta": {
    "limit": 1,
    "next_cursor": "string"
  }
}

{
  "reason": "string"
}

{
  "data": {
    "approval_id": "74438200973594624",
    "project_id": "74438200973594624",
    "execution_id": "74438200973594624",
    "flow_id": "74438200973594624",
    "node_key": "string",
    "operation_code": "generate_email",
    "note": "string",
    "status": "pending",
    "decided_by": "string",
    "decided_by_user_id": "74438200973594624",
    "decided_by_name": "string",
    "reason": "string",
    "expires_at": "2026-10-02T09:30:00Z",
    "created_at": "2026-10-02T09:30:00Z",
    "decided_at": "2026-10-02T09:30:00Z"
  }
}

{
  "reason": "string"
}

{
  "data": {
    "approval_id": "74438200973594624",
    "project_id": "74438200973594624",
    "execution_id": "74438200973594624",
    "flow_id": "74438200973594624",
    "node_key": "string",
    "operation_code": "generate_email",
    "note": "string",
    "status": "pending",
    "decided_by": "string",
    "decided_by_user_id": "74438200973594624",
    "decided_by_name": "string",
    "reason": "string",
    "expires_at": "2026-10-02T09:30:00Z",
    "created_at": "2026-10-02T09:30:00Z",
    "decided_at": "2026-10-02T09:30:00Z"
  }
}

Examples

Read the requests that wait

One execution waits for a decision on its node review. The note is the one the author of the flow left on the node.

curl "https://api.slen.ai/api/v1/approvals?status=pending" \
  -H "Authorization: Bearer $SLEN_API_KEY"

{
  "data": [
    {
      "approval_id": "74443031076798464",
      "project_id": "74438200973594624",
      "execution_id": "74443028719599616",
      "flow_id": "74438623450128384",
      "node_key": "review",
      "operation_code": "generate_email",
      "note": "Check the tone before the email goes out.",
      "status": "pending",
      "decided_by": null,
      "decided_by_user_id": null,
      "decided_by_name": null,
      "reason": null,
      "expires_at": "2026-10-03T09:20:11+00:00",
      "created_at": "2026-10-02T09:20:11+00:00",
      "decided_at": null
    }
  ],
  "meta": {
    "limit": 30,
    "next_cursor": null
  }
}

Approve a request

The answer is the approval with the verdict and the key that gave it.

curl -X POST https://api.slen.ai/api/v1/approvals/74443031076798464/approve \
  -H "Authorization: Bearer $SLEN_API_KEY"

{
  "data": {
    "approval_id": "74443031076798464",
    "project_id": "74438200973594624",
    "execution_id": "74443028719599616",
    "flow_id": "74438623450128384",
    "node_key": "review",
    "operation_code": "generate_email",
    "note": "Check the tone before the email goes out.",
    "status": "approved",
    "decided_by": "74438344587730944",
    "decided_by_user_id": null,
    "decided_by_name": null,
    "reason": null,
    "expires_at": "2026-10-03T09:20:11+00:00",
    "created_at": "2026-10-02T09:20:11+00:00",
    "decided_at": "2026-10-02T09:31:40+00:00"
  }
}

Reject a request

The reason is kept with the approval. The execution leaves the node through Rejected.

curl https://api.slen.ai/api/v1/approvals/74443031076798464/reject \
  -H "Authorization: Bearer $SLEN_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "reason": "The customer asked us not to write again."
  }'

{
  "data": {
    "approval_id": "74443031076798464",
    "project_id": "74438200973594624",
    "execution_id": "74443028719599616",
    "flow_id": "74438623450128384",
    "node_key": "review",
    "operation_code": "generate_email",
    "note": "Check the tone before the email goes out.",
    "status": "rejected",
    "decided_by": "74438344587730944",
    "decided_by_user_id": null,
    "decided_by_name": null,
    "reason": "The customer asked us not to write again.",
    "expires_at": "2026-10-03T09:20:11+00:00",
    "created_at": "2026-10-02T09:20:11+00:00",
    "decided_at": "2026-10-02T09:31:40+00:00"
  }
}

Where to go next

• Approvals — the same requests in the console.

• Async runs and waiting — how an execution that waits for a decision answers.

• Webhooks — approval.requested and approval.decided, and how they arrive.

• Error codes — what each code of this page means and what to do about it.