# One session's closing measurements

> FirmTape's derived closing summary of one finished session: open, close, high, low, the zero-gamma flip and its crossings, the walls, the net-gamma percentile, ATM IV. No key.

Source: https://firmtape.com/docs/developers/replay/session

FirmTape's derived closing summary of one finished session: open, close, high, low, the zero-gamma flip and its crossings, the walls, the net-gamma percentile, ATM IV. No key.

`GET /api/session/{day}`

Plan Free · No key · Version 1.1.0 · Since 2026-09-01

**This endpoint serves:** [REPLAY: The session archive and session pages](https://firmtape.com/docs/replay#session-archive), [REPLAY: The terminal, free on every finished day](https://firmtape.com/docs/replay#free-replay). **Plan:** [Free](https://firmtape.com/features/replay). Free, no account

## Parameters

| Name | What it does | Default | Error |
| --- | --- | --- | --- |
| `day` (required) path, string | Finished SPX trading day |  |  |

## Response

Public derived session summary

| Field | Meaning | Unit |
| --- | --- | --- |
| `day` (string) |  |  |
| `url` (string) |  |  |
| `previous_day` (string \| null) |  |  |
| `next_day` (string \| null) |  |  |
| `open` (number) |  |  |
| `close` (number) |  |  |
| `high` (number) |  |  |
| `low` (number) |  |  |
| `vwap_close` (number \| null) |  |  |
| `zero_gamma_flip` (number \| null) |  |  |
| `call_resistance` (number \| null) |  |  |
| `put_support` (number \| null) |  |  |
| `atm_iv_open` (number \| null) |  |  |
| `net_gamma_percentile` (number \| null) |  |  |
| `flip_crossings` (integer) |  |  |
| `source` (string) |  |  |

## Errors

| Status | Code | What to do |
| --- | --- | --- |
| 404 |  | Unknown, live or unavailable session. |

## Request

```sh
curl \
  "https://firmtape.com/api/session/2026-10-09"
```

```python
import os, requests

H = {}
r = requests.get("https://firmtape.com/api/session/2026-10-09", headers=H)
print(r.status_code, r.text[:500])
```

```js
const r = await fetch("https://firmtape.com/api/session/2026-10-09", {
  method: "GET",
  headers: {  },
});
console.log(r.status, await r.text());
```

## Changes

- 2026-09-01: Added.