# Compare live with the test

Source: https://langbot.ai/docs/api/monitoring/get-vs-test

`GET /v1/bots/{bot_id}/vs-test`

Live against the Sim run the bot is linked to: fill rate, fee per contract, P&L per contract and slippage against tested prices, each with its sample sizes.

**Auth.** An account token (`Authorization: Bearer lb_…`) or a signed-in web session. A report-only token (`lbr_…`) is refused here with `403 scope_denied`.

**Limits.** Counts against your plan's API requests (60, 600 or 3,000 a minute on Free, Builder and Standard).

## Parameters

### Path parameters

| Name | Type | Required | Description |
|---|---|---|---|
| `bot_id` | string | yes | The bot id (`bot_…`). |

### Query parameters

| Name | Type | Required | Description |
|---|---|---|---|
| `since` | integer | no | Start of the live window, ms epoch (default: when the bot was created). |

## Request

**curl**

```bash
curl "https://api.langbot.ai/v1/bots/bot_01M6G72RFQRQ8JGNG8T1447GGP/vs-test" \
  -H "Authorization: Bearer $LANGBOT_API_TOKEN"
```

**Python**

```python
from langbot import LangbotClient

async with LangbotClient() as lb:  # reads LANGBOT_API_TOKEN
    v = await lb.bots.vs_test("bot_01M6G72RFQRQ8JGNG8T1447GGP")
    if v["available"]:
        m = v["metrics"]["fill_rate"]
        print(m["live"], m["tested"], m["live_n"], m["tested_n"])
```

**TypeScript**

```ts
import { LangbotClient } from "@langbotai/sdk";

const lb = new LangbotClient(); // reads LANGBOT_API_TOKEN
const v = await lb.bots.vsTest("bot_01M6G72RFQRQ8JGNG8T1447GGP");
```

## Response

`200 OK`

```json
{
  "test_run_id": "run_01M6F9\u2026",
  "available": true,
  "reason": null,
  "window": {
    "since": 1793690000000,
    "until": 1793693150782
  },
  "metrics": {
    "fill_rate": {
      "live": 0.8,
      "tested": 0.5,
      "diff": 0.3,
      "live_n": 20.0,
      "tested_n": 100.0,
      "unit": "contracts ordered"
    },
    "fee_per_contract": {
      "live": 0.01,
      "tested": 0.02,
      "diff": -0.01,
      "live_n": 16.0,
      "tested_n": 50.0,
      "unit": "contracts filled (with a known fee)"
    },
    "pnl_per_contract": {
      "live": 0.031,
      "tested": 0.1,
      "diff": -0.069,
      "live_n": 16.0,
      "tested_n": 50.0,
      "unit": "contracts filled"
    },
    "slippage": {
      "cents": 2.0,
      "markets_compared": 1,
      "live_fills": 1,
      "tested_fills": 1,
      "by_market": [
        {
          "ticker": "KX-T1",
          "side": "yes",
          "action": "buy",
          "live_avg_price": 0.4,
          "tested_avg_price": 0.38,
          "cents": 2.0,
          "live_contracts": 16.0,
          "tested_contracts": 50.0,
          "live_fills": 1,
          "tested_fills": 1
        }
      ]
    }
  },
  "slippage_reason": null
}
```

Each number comes with the sample behind it (`live_n`, `tested_n`, in `unit`); no significance test is claimed, so read small samples as small. `slippage` is in cents, weighted by live contracts, positive when live bought higher or sold lower than the test, over markets present in both; it is usually `null` (`slippage_reason`), because a test replays a past event. `available: false` with a `reason` when the bot has no linked run, or the run has no scorecard.

## Errors

| Status | `code` | When |
|---|---|---|
| 404 | `not_found` | No bot with that id on your account (or it was deleted). |
| 401 | `auth_required` | No token was sent. |
| 401 | `token_invalid` | The token was not recognised (mistyped, revoked or expired). |
| 422 | `validation_error` | A parameter failed validation; `detail[].loc` names it. |
| 429 | `rate_limited` | Over your request budget; wait `Retry-After` seconds. |

Every error body is `{"detail": …, "code": "…"}`; branch on `code`. All codes: [Errors](https://langbot.ai/docs/api#errors).