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

# Period IDs

Periods define the time segment of a game that a market applies to. Each period has a numeric `period_id`. Prematch and live periods use separate ID ranges.

## Prematch Periods

| Period             | ID | Description          |
| ------------------ | -- | -------------------- |
| Full Game          | 0  | Prematch full game   |
| 1st Half           | 1  | Prematch first half  |
| 2nd Half           | 2  | Prematch second half |
| 1st Quarter/Period | 3  | Prematch Q1          |
| 2nd Quarter/Period | 4  | Prematch Q2          |
| 3rd Quarter/Period | 5  | Prematch Q3          |
| 4th Quarter/Period | 6  | Prematch Q4          |

<Note>
  Tennis uses `period_id=0` for prematch full-match markets. Set-specific prematch markets reuse period IDs `3` and `4` for Set 1 and Set 2.
</Note>

## Live / In-Play Periods

| Period           | ID | Description       |
| ---------------- | -- | ----------------- |
| Live Full Game   | 7  | In-play full game |
| Live 1st Half    | 13 | In-play 1st half  |
| Live 2nd Half    | 14 | In-play 2nd half  |
| Live 1st Quarter | 15 | In-play Q1        |
| Live 2nd Quarter | 16 | In-play Q2        |
| Live 3rd Quarter | 17 | In-play Q3        |
| Live 4th Quarter | 18 | In-play Q4        |

<Note>
  Tennis uses `period_id=7` for live full-match markets. Live set-specific markets use `period_id=15` for Set 1 and `period_id=16` for Set 2.
</Note>

## V1 Best-Line Period Names

In the V1 best-line endpoint, periods are referenced by string names rather than numeric IDs. The mapping is as follows:

| Numeric ID | V1 Period Name         |
| ---------- | ---------------------- |
| 0          | `period_full_game`     |
| 1          | `period_first_half`    |
| 2          | `period_second_half`   |
| 3          | `period_first_period`  |
| 4          | `period_second_period` |
| 5          | `period_third_period`  |
| 6          | `period_fourth_period` |