<p>Every website may have a different way of aggregating this sort of data. I would expect that the exact method used by each website will be determined by their specific needs/applications. There is no absolute "right or wrong way" to get this job done. For example:</p>

<ul>
<li>A simple implementation someone makes for fun might just display the average of two different API calls</li>
<li>A firm like the CME will pull data from only the most legitimate sources, with external considerations to ensure the price data cannot be manipulated to game futures trades on their exchange</li>
</ul>

<p>To find more info on some actual implementations, I would suggest looking up some websites that display data in the way you're looking for, and see if they provide any info on the algorithms/methods used. I would guess at least a few sites make that info public.</p>

CC BY-SA 3.0
2018-02-02T01:41:43.457Z
2018-02-02T01:41:43.457Z
chytrik
<p>There are websites with historical data of coins. How do they get it?</p>

<p>Do they get the price from 10 exchanges at the same time, then divide by 10?</p>

CC BY-SA 3.0
2018-02-01T23:27:24.307Z
Every website may have a different way of aggregating this data. The method you mentioned would work as long as none of the exchanges report bad data.
chytrik
CC BY-SA 3.0
2018-02-01T23:29:51.770Z
@chytrik do you know where I can find the different ways that websites do it?

I imagine some check the set of prices for outliers before averaging, and some may even give weight to some exchanges more, right?

Thanks for answering
Kyle Graham
CC BY-SA 3.0
2018-02-02T00:05:23.407Z
if I were you I would start by checking out some websites that provide a service like this, and see if they publish any info on their specific algorithms. There is no "right or wrong way" to do something like that, your method will likely need to be determined by your specific needs/application.
chytrik
CC BY-SA 3.0
2018-02-02T00:11:50.280Z
@chytrik alright, if you write up what we discussed, I will mark it as the accepted answer
Kyle Graham
<exchanges><altcoin><raw-data><historical-trade-data><stocks>
How do websites get prices for a coin?
Kyle Graham
# How do websites get prices for a coin?

(Asked by: username_0 on 2018-02-01)

There are websites with historical data of coins. How do they get it?

Do they get the price from 10 exchanges at the same time, then divide by 10?

**Tags:** exchanges, altcoin, raw-data, historical-trade-data, stocks

> **Comments:**
> **username_1**: Every website may have a different way of aggregating this data. The method you mentioned would work as long as none of the exchanges report bad data.  
> **username_0**: @username_1 do you know where I can find the different ways that websites do it?  I imagine some check the set of prices for outliers before averaging, and some may even give weight to some exchanges more, right?  Thanks for answering  
> **username_1**: if I were you I would start by checking out some websites that provide a service like this, and see if they publish any info on their specific algorithms. There is no "right or wrong way" to do something like that, your method will likely need to be determined by your specific needs/application.  
> **username_0**: @username_1 alright, if you write up what we discussed, I will mark it as the accepted answer  

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## 1 answers

### Answer by username_1 on 2018-02-02. Score: 0 | Accepted answer

Every website may have a different way of aggregating this sort of data. I would expect that the exact method used by each website will be determined by their specific needs/applications. There is no absolute "right or wrong way" to get this job done. For example:

* A simple implementation someone makes for fun might just display the average of two different API calls
* A firm like the CME will pull data from only the most legitimate sources, with external considerations to ensure the price data cannot be manipulated to game futures trades on their exchange

To find more info on some actual implementations, I would suggest looking up some websites that display data in the way you're looking for, and see if they provide any info on the algorithms/methods used. I would guess at least a few sites make that info public.


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