
My acquired Bitcoin startup Bridgewalker is now open source - jav
https://www.bridgewalkerapp.com/blog/2014/01/07/bridgewalker-open-source/
======
jav
Some background: It's an Android wallet, where you maintain a euro balance
(held by Bridgewalker for you). Using those funds, bitcoins will be bought at
current market price whenever you want to send any. This allows you to use
Bitcoin only as a payment mechanism, without being affected by the exchange
rate volatility. You fund your account via Bitcoin as well, which will be
exchanged for euros at current market price and credited to your account.

So: Bitcoin as transaction mechanism, Euro as store of value.

~~~
meleva
Bitcoin newbie here, so it's probably something obvious, but can I buy Bitcoin
from this app ? I wasn't sure if the "receive Bitcoin" meant that.

~~~
jav
No, you cannot use this app to buy bitcoins. So I'm afraid it does not solve
one of the hardest challenges Bitcoin still faces, which is how to get any.
You'll have to figure out the best/cheapest way depending on where you are.

If you happen, for example, to stand in front of a Bitcoin ATM, you can use
that to turn fiat that you have in the form of cash into fiat that you have in
your Bridgewalker account (by buying Bitcoin from the ATM and sending it to
your Bridgewalker address), which you can then later spend wherever it says
"Bitcoin accepted here".

A lot of exchanging back and forth for sure, but basically the idea of
"Bitcoin only as tranfer mechanism" applied at every step. It's also just a
technical prototype. In practice it might make sense to cut some of those
exchange fees by having a more direct way to fund your account, at the cost of
only being available in certain markets/countries. For this prototype I went
with the easiest solution: only Bitcoin in, and Bitcoin out.

------
JoshTriplett
Quite nice to see that this is written in Haskell.

The idea of a bitcoin app that stores funds in another currency makes a lot of
sense for people who primarily want to use bitcoin as an exchange mechanism
without speculating on its future value.

I'm curious what service this uses to purchase bitcoins, or if it uses its own
exchange; it's not comforting to see a reference to the MtGox API, but
hopefully they're only used to find out the current value. (Even then, they're
not a reliable metric for the true value of bitcoins, since they're not
sufficiently liquid with respect to governmental currencies, but that'd still
be better than actually attempting to use them as a currency exchange.)

~~~
jav
It does use Mt.Gox in the background for the actual exchange process. There is
not enough volume (yet) to make an internal exchange practical, there would be
too much risk at the moment, at least for my taste.

When I started on this project, Mt.Gox was pretty much the only choice,
because of the large market share (> 80% at the time) and the necessary volume
and small enough market spread. Their withdrawal delays are annoying, that's
true. It does not affect me directly, since it's only Bitcoin in and Bitcoin
out for me, where so far Mt.Gox had pretty much never delays. But it does
distort the market price, which means you get a great rate when you fund your
Bridgewalker account (because BTC is overvalued on Mt.Gox) and get a bad rate
when you spend it (again, because BTC is overvalued on Mt.Gox) - so in the end
it kind of zeroes out for you as a user, but it's still confusing for the
user, why you have this offset.

There aren't many alternatives though. Bitstamp could be one, but I'm worried
that they still might run into regulatory issues down the line. Also none of
the other exchanges offer real-time streaming updates about changes to the
order book, like Mt.Gox does, which is very useful to keep track of the
market. Kraken could be an interesting alternative to Mt.Gox, since they seem
to run a solid operation. If they add such a streaming API with real-time
updates about the order book and maybe get some more volume, then I would
consider switching the backend over.

Or someone else does it first - it's open source now, after all! ;-)

Or maybe you could hedge the whole thing just with some financial swap
construction, but I haven't looked into that too much and it's not my area of
expertise. I would be interested to find out how much something like that
would cost in terms of overhead/fees and who would be a partner to provide
such financial services for Bitcoin. If you have some input regarding this,
feel free to contact me - my email address is on the Bridgewalker website.

------
knocte
this is awesome!

btw if you plan to make an iOS app, maybe you'll be delighted to know that you
can apply as an open source developer to free Xamarin licenses:
[http://resources.xamarin.com/open-source-
contributor.html](http://resources.xamarin.com/open-source-contributor.html)

(I guess writing F# would make you happier than ObjectiveC, given that you
wrote your server side in Haskell ;)

------
kvinnako
This is great. These kinds of open sourced production apps help people adapt
more of haskell.

