> ## Documentation Index
> Fetch the complete documentation index at: https://docs.fiveninelabs.com/llms.txt
> Use this file to discover all available pages before exploring further.

# not_found

> 404 not_found — the id is unknown, or the resource isn't owned by this account. Indistinguishable by design.

**HTTP 404 · type `not_found`.** The id doesn't exist — or it exists but belongs to a
different account. The two cases are deliberately indistinguishable: a 404 never
confirms that someone else's session id is real.

## The shape

```json theme={null}
{
  "error": {
    "type": "not_found",
    "code": "not_found",
    "message": "No session sess_0aaaa is visible to this account.",
    "doc_url": "https://docs.fiveninelabs.com/errors/not_found",
    "request_id": "req_6bb90x"
  }
}
```

<Warning>
  **A planned route is a 501, not a 404.** Everything marked `x-fn-status: planned`
  in the [API reference](/api-reference) (discover, extractions, monitors, refresh,
  redaction, `GET /v1/receipts/{id}`, webhook test/redeliver, `/mcp`) answers
  **`501 not_implemented`** with a `surface` field naming what is missing — see
  [not\_implemented](/errors/not_implemented). Do not branch on 404 to detect an
  unshipped route; branch on 501.

  **One other thing does still answer 404, honestly stated:** a **wrong HTTP method
  on a known path** (a 405 is planned). If a route you're sure exists 404s, check the
  verb before hunting for an ownership problem.
</Warning>

## How to fix

* Check the id's prefix against the resource: `sess_` for sessions, `ext_` for
  extractions, `mon_` for monitors, `whep_` for webhook endpoints. A `sess_` id on
  `/v1/webhooks/{id}` is a 404, not a type error. (The extractions and monitors
  surfaces answer `501` on every id, right prefix or wrong — they aren't served yet.)
* Confirm you're calling with a key from the **same account** that created the
  resource — keys on other accounts see nothing, by design. `fn_test_` and `fn_live_`
  keys share the account, so that split is not the cause.
* List what the account can actually see: `GET /v1/sessions` (covers extractions and
  monitor runs via `type`).
* Redaction is **planned, not served** — `DELETE /v1/sessions/{id}` answers `501`
  today, so nothing you can call yet produces a redacted run. When it ships, a
  redacted run will keep its ledger skeleton while its data reads 404; if you rely
  on long-lived reads, note runs are retained at least 90 days.

## Reproduce it

Works on an `fn_test_` key, \$0:

```bash theme={null}
curl https://api.fiveninelabs.com/v1/sessions/sess_0doesnotexist \
  -H "Authorization: Bearer $FIVENINE_TEST_KEY"
```