# Data source for option historical bars?

**URL:** <https://forum.alpaca.markets/t/data-source-for-option-historical-bars/17704>\
**Category:** Alpaca Market Data\
**Created:** [August 26, 2025, 9:49am UTC](https://forum.alpaca.markets/t/data-source-for-option-historical-bars/17704 "2025-08-26T09:49:18Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Mysterious\_Shadow](https://sea2.discourse-cdn.com/flex020/user_avatar/forum.alpaca.markets/mysterious_shadow/32/7459_2.png) [@Mysterious\_Shadow](https://forum.alpaca.markets/u/Mysterious_Shadow)\
**Post date:** [August 26, 2025, 9:49am UTC](https://forum.alpaca.markets/t/data-source-for-option-historical-bars/17704/1 "2025-08-26T09:49:18Z")

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I’m looking at:

> **[Historical bars](https://docs.alpaca.markets/reference/optionbars)**
>
> The historical option bars API provides aggregates for a list of option symbols between the specified dates. The returned results are sorted by symbol first, then by bar timestamp. This means that you are likely to see only one symbol in your first...

For a free user, what data am I getting / where am I getting the data from for ohlcv option bars (not quotes or trades)? And is the data delayed by 15 minutes? Thanks.

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**Author:** ![Dan\_Whitnable\_Alpaca](https://sea2.discourse-cdn.com/flex020/user_avatar/forum.alpaca.markets/dan_whitnable_alpaca/32/1658_2.png) [@Dan\_Whitnable\_Alpaca](https://forum.alpaca.markets/u/Dan_Whitnable_Alpaca)\
**Post date:** [August 26, 2025, 1:00pm UTC](https://forum.alpaca.markets/t/data-source-for-option-historical-bars/17704/2 "2025-08-26T13:00:38Z")

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@Mysterious_Shadow There is really only one data source for option data which is OPRA ([Options Price Reporting Authority](https://www.opraplan.com/)). They are a securities information processor registered with the SEC who collects and disseminates trade and quote data for all US exchange listed option contracts. They do not provide data for free. Due to licensing only data older than 15 minutes can be displayed without restrictions. Real time OPRA data requires an Algo Trader Plus subscription.

The free Basic market data subscription provides access to OPRA data older than 15 minutes (ie delayed 15 minutes). All bars for example are calculated with OPRA data. The free subscription simply limits queries from the most recent 15 minutes (if you do not include an `end` parameter in your query the system 1) looks up your data subscription then 2) defaults the `end` to the latest available for your subscription).

To help with debugging, when you are simply getting code to work and may not want to pay for data, Alpaca provides ‘Indicative’ data. This is actual OPRA data but randomized a bit. It’s not real data, but it’s close. This avoids licensing issues while still providing good test data. Indicative data should not be used for live trading.

So, to answer your specific question “_where am I getting the data from for ohlcv option bars (not quotes or trades)? And is the data delayed by 15 minutes?_” Bars are always OPRA data. One simply is blocked from fetching the most recent 15 minutes with the free Basic subscription.