Betfair API-NG

[marksmeets302]

Hi Peter,

I did some digging in my email box. Here's something I sent to betfair on October 3rd. I think it explains the problem:

Hi,

I'm in the process of converting my software to the new API, and ran into something that puzzles me. Attached is a screenshot of a race at dundalk. All matches are shown. But I don't understand the what-if figures. For instance, should Michaelmas win, according to the website I should get 4.88 euros. But using my own calculations I arrive at quite a different number:

receive 12 x (56.67 - 1) = 668.04 because of the back on Michaelmas
receive 4.7 because of the lay on Magnolia beach
receive 4 because of the lay on Paene Magnus
Total to receive: 676.74

pay 10.95 x (61.50 -1) = 662.475 because of the lay on Michaelmas
pay 4 because of the back on Magnolia beach
pay 4 because of the bak on Paene Magnus
Total to pay: 670.475

Total to receive: 6.265

This is quite different from 4.88, commissions cannot explain it. The numbers for the other runners seem to be off as well. The simplest one is if none of the horses I bet on wins. Then I lose all my back stakes (4 + 4 + 12 = 20) and receive all my lay stakes (0.11 + 4.70 + 1.78 + 2.11 + 3.88 + 3.86 + 3.21 = 19.65). In other words: minus 35 cents. But the website shows -0.32.

Am I doing something wrong or is this a problem on betfairs end? If you want to examine, this was on my account <removed>, for the Fri 3 Oct 1m2f Grp3 20:40 Dundalk (20:40 is CET)

--------
Later on, I added this:

Hi, I'd like to add some more information. I think my calculations are correct, because in the end betfair agrees... According to me a loss of 35 cents should be booked if none of the horses I bet on wins. According to the betting interface, it would be 32 cents. None of the horses won indeed, and my p&l showed a loss of 35 cents (screenshot attached). So there appears to be a mismatch between the figures on the betting interface and the actual calculations carried out when computing the p&l.

For me this concludes the problem, but I thought you would like to know about it.

(Well, I stated that for me the problem was no longer relevant, but since I don't fully trust my program yet every once in a while I'm lured into the trap of believing the what-if figures on the site. Worse it slows down fixing my program tremendously)

Mark

[marksmeets302]

Hmm. Can't seem to add the image. Maybe like this:



Well, it still only shows half the image. Scaling it will make it unreadable. If you want to see the full picture, get it at betfair.marksmeets.nl/pictures/betangel1.png

Mark.

[blueport]

Is anyone in Oz actually maintaining a steady connection?

I've tried tweaking as much as i can but it's still very erratic. Response times frequently spike between 500-1000ms and stay there for 2-3 seconds before dropping back down to 50.

I'm interested to know if it's just me having these issues.

[blueport]

What does this line in the log mean?

Exception: Exception of type 'BetAngelHelper.APINGException' was thrown.

[Naffman]

Is anyone in Oz actually maintaining a steady connection?

I've tried tweaking as much as i can but it's still very erratic. Response times frequently spike between 500-1000ms and stay there for 2-3 seconds before dropping back down to 50.

I'm interested to know if it's just me having these issues.

I've been having the same problems, I thought it was just me!

[blueport]

I hope this is not what we have to deal with going forward.

Reliability is out the window.

[marksmeets302]

Just heard back from the guys at betfair. They have planned an upgrade of the site in January. What is a bit worrying is that they believe the incorrect what-if figures are a result of a new way of rounding. Well, since they are sometimes off by a thousand or so that seems far fetched...

Mark

[Naffman]

Just heard back from the guys at betfair. They have planned an upgrade of the site in January.

Mark

That is very worrying! Have they taken their Christmas break already?

[Euler]

It’s due to the difference in the rounding calculation that we are currently using (vs the old website) and is exacerbated when large number of small bets fragments are matched at high odds.
The plan is to address this issue in Jan next year as part of the ongoing improvements to the new Betfair Exchange website.

[Westerner]

Had huge problems using the API for the Aus v SA cricket this morning. Freezing/stickiness made things practically impossible.

How Betfair think this is acceptable is beyond me.

[Euler]

I had a good moan at them this morning on the Aussie stuff. In my mind unusable this morning.

I wonder whether to solve the failed call issue they have put in a fix that has just completely broken it. Up to that point the site worked but the call to get a market often failed. We managed to put in a work around to that. But can't work around this performance issue.

It is amazing to see them torpedo the usability like this. I won't trade the Aussie stuff tomorrow because of it.

[Euler]

Do they not use the exchange themselves? Surely they must at least log in and use it?

[Westerner]

It's incredible and gut wrenching to see them do so much damage to what they've done so well at creating over the last 14 years.

Once users lose confidence in their product (which I have this week) it's a slippery slope.

Just hope they can rectify these issues very quickly although I'm not holding out much hope. I pushed things this morning (when maybe I shouldn't have) and paid the price when things totally froze and got stuck in a position.

Truth is, I won't be able to continue trading if this goes on much longer - it just won't be practical.

Must be so frustrating for you guys who have to deal with Betfair regarding this change.

Thanks for your efforts and the updates.

[marksmeets302]

To be fair, I think it's good that betfair invests in new technology. The idea is that the engine behind the new api allows them to scale better which in the long run will only be beneficial to us. And the guys at technical support (bdp) are usually really helpful.

But Peter has a good point: do they even look at their own site? I mean the wrong what-if figures could result in real legal issues. Suppose a customer goes to court and presents a screenshot showing he won money according to the what-ifs, but lost a multiple of it in reality?

Mark

[LinusP]

Peter do you know how long APING will be free? It states till at least 5th Jan 2015 but do you know what the pricing structure will be after that?