Bitcoin Forum

I am excited to announce the launch of "Bridgewalker". After giving Instawallet into the capable hands of Paymium, I had some time to focus on this new project, which I believe is an important stepping stone in making Bitcoin more useful while it is still under the influence of the volatility of its small market.

The basic idea is simple: Bridgewalker is a (hosted) Bitcoin wallet for Android smartphones, which allows you to receive and send bitcoins. So far, pretty standard. The difference is, that you will never hold bitcoins for more than a few seconds, as Bridgewalker will automatically exchange them for Euros as soon as you receive them (and they confirm) and will only buy bitcoins just that moment when you are about to send them. You can therefore use Bitcoin solely as a payment network, while being protected from market swings.

https://www.bridgewalkerapp.com/img/bg/bridgewalker_with_device_art_small.png

  Get the app at: https://www.bridgewalkerapp.com/ !

A word about fees: You might assume that all that exchanging back and forth is prohibitively expensive. But it is actually not too bad (in my opinion), although there is certainly room for improvement. The fee for a "round trip" currently works out to around 1.5 %. Which means, if you send 1 BTC to Bridgewalker and then back right away, you are left with 0.985 BTC. This includes both exchange fees and losses through market spread (Bridgewalker currently uses Mt.Gox for currency exchange). The fees should go down though, as Bridgewalker's volume increases.

One additional feature: Green addresses (https://en.bitcoin.it/wiki/Green_address) make a comeback here. Bridgewalker accepts transactions from certain green addresses (at the moment only Mt.Gox) instantaneously and in turn sends out transactions that can be identified by the green address 1MAxx46Dp3tFw933PxPwEYYGCpxYda2pyH .

Feedback and comments much appreciated! :-)

Edit: Updated description to account for change of counter currency from USD to EUR (11/2013).

Edit: Bridgewalker has been acquired by Hive (https://bitcointalk.org/index.php?topic=304060.0;all)! (11/2013).

Edit: Bridgewalker is shutting down (03/2014).

Sounds like a very interesting direction! In what manner does the receiving party accept the Dollars? How does one transfer Dollars into the service?

Something like this will be the killer app that brings Bitcoin into Joe/Jane average's living room/phone handset.

While nerds like us would probably rather hold bitcoin than bankster paper, a method for peeps to hold fiat while using Bitcoin purely as a payment network is ingenious and needed: perfect competition for Western Union and its ilk.

The "interface" to the rest of the world, so to speak, is only Bitcoin. Bitcoin in, Bitcoin out. So in order to fund the account, you will have to buy bitcoins from somewhere else and transfer them. That might seem like an unnecessary step (use USD to buy BTC, just to have Bridgewalker convert it back), but I cannot and do not want to accept USD. Others are much better at selling coins and Bitcoin is the universal glue between us.


Thanks! I absolutely agree. This is certainly not for everyone and I am all for doing everything directly in BTC. But this is a middle ground for people who are not quite ready to trust some weird internet money, but see the appeal in the Bitcoin payment mechanism as a kind of "cash for the digital world".

FAN-TAS-TIC  :)

Yet another portion of my prediction from the Solution to the Bitcoin Foundation (https://bitcointalk.org/index.php?topic=115303.0) post coming true.





And as for this:


You're not only protected from market swings, but as I also said in my post from 51% attacks:


In other words, I see a future where people do not use bitcoins (or other cryptocurrencies) as their main store of value. They are too volatile and unpredictable; even further down the line there are many unknowns. Instead people will use crypto-coins for what they are best at which is transferring value. They will probably use gold/pm's for what they are best at, which is storing value. Many people will hold bitcoins, and other cryptocurrencies only long enough to get what they need. There will always be investors and speculators, of course, but primarily no cryptocurrency will be used in the way people now use cash, where they keep 99% of their wealth permanently stored there.

great job!

Jan I don't have an android phone but can you test something for me.

1.  on the phones web browser go here and click on the URI link in the first section.

http://lovebitcoins.org/developers.html (http://lovebitcoins.org/developers.html)

does it open your wallet app and pre-compose a send bitcoins transaction with the address and amount filled in?  and then wait for the "send" button to be pressed?

2.  use your app to scan the QR code in the second section. does it also bring in the address and amount?

if so we will add you to the recommended wallets list on BitPay as being fully URI compatible

https://bitpay.com/bitcoin-compatible-wallets (https://bitpay.com/bitcoin-compatible-wallets)

Looks impressive. I'm sure a lot of people will find this useful.

But what about trust? Namely, who does the user have to trust?

I skimmed the website, and it wasn't clear to me what happens when an account is created. Is this an account with the Bridgewalker service? Or with Mt. Gox? Do you have access to the bitcoin transactions involved in using this app? What about the Mt. Gox accounts used?

Super creative idea. I love it.

ONLY 1.5% oh boy. Thats only if you never actually use that $ balance...  if you ever actually transfer that in or out of gox to use is the real world, that % is larger than credit cards will ever be.

Payment vehicle rather than speculative instrument this I believe is what btc should be.   ;D

Glad you like it! :-) .. I agree with some of the points you make! Although personally I would rather see something like Bridgewalker becoming obsolete in the long run and - as the Bitcoin economy matures - things moving completely over into BTC. If only for efficiency reasons (avoid constant currency exchange). But at the moment that's simply not practical and probably will not be for quite some time. The popularity of payment processors like BitPay show, that at this point it is necessary to peg prices to USD because there is just too much volatility. And that's fine. This tool aims to bring the same concept to the customer side. Where merchants accept BTC and end up with USD, customers can use Bridgewalker to hold USD and pay in the form of Bitcoin transactions. The important point is, that Bitcoin is the neutral interface between them.


Scanning the QR code works! I support both things like "bitcoin:1asdf?amount=0.123" as well as the "broken" variant with "bitcoin://1asdf"

The URI link does not work at the moment, I haven't looked into where exactly I need to hook into there. But I definitely plan to support that! I'll let you know, when an update is available.


Aw, yes, I should put more details about that on the site. The account is with Bridgewalker and all Bitcoin transactions are going to and from Bridgewalker's Bitcoin daemon. Bridgewalker in turn has then one single account with Mt.Gox and transfers bitcoins between it's own wallet and the account at Mt.Gox to do the trading. The end result is, that most user funds end up in Bridgewalker's Mt.Gox account in the form of USD. So you need to trust that a) Mt.Gox keeps their user accounts safe in general and b) I keep the access to Bridgewalker's Mt.Gox account in particular safe. Only a small amount of funds are in BTC at any time, basically just a small hot wallet to be able to send out transactions quickly.

I'll answer more questions later, as I will be away from the computer for a few hours. Thanks for all the feedback so far!

I was just going to say the same :)

jav: are you considering to release the source code at some point?

This is pay pal without high fees. Very clever.

Awesome!  see what is required to register the bitcoin: protocol in AndroidOS.  BitcoinSpinner and the Andreas Wallet both support this, so the client source code should be able to tell you how its done.

This Is exactley what bitcoin needs to go into mainstream. I have been putting steps in place to develop a similar app for Australian users. Bitcoin needs people to be forward thinkers like this to push it along.   

Fascinating.

Now - since you're using Gox...

What about currency conversion?  What if I have two accounts with Gox; one in dollars and one in Francs, and I want to settle up with a Frenchman?  Can I send my dollars to your server and have them come out as Francs on the other person's phone?

When can I do that?

And should it cost any extra, or will there be some kind of conversion vigorish?

Inquiring minds want to know...

EDIT:  Should I even need a Gox account in Francs to send Francs with my dollars?  Shouldn't a proper Bridgewalker/Gox interface be able to take care of that?

EDIT #2:  Euros.  Heh.  Old habits die hard...

You solved the problem

I think he did.

No.  He solved two problems.

Firstly - it brings complete anonymity to bitcoin.  No bank account required - USD are passed around just like cash.  And no Gox account required either, with all of its registration requirements.  With a burner phone paid for with VISA/Master Gift Cards (a phone with a removable battery), it's untraceable.

Eventually you get out your bitcoin to a fresh wallet - or send USD to someone who will hand you the cash.

Secondly - this is how to get bitcoin into anyone's hands quickly and easily.  Every friend you've got:  "Install Bridgewalker and I'll send you that twenty...".  Or:  "...and I'll pay you for that car".  EU cash restrictions are irrelevant, once this is enabled for Euros.

This is awesome.

I advise you to support multiple exchanges as soon as possible.

And get your server/servers somewhere other than the US...

This thing is centralized in two places.  Kill the Bridgewalker servers, it dies, kill MtGox, it dies.

Only in the Bitcoin world would this:

Turn into this:


LOL!  Everyone is trying to protect the guy for solving a problem... this only happens here.  

If he was working with anything else,  made a computer 20% faster,  made his phone battery last 4 times longer,  if he found a way to convert dollars to gold, he'd be a hero (those Gold ATM's made headlines for months).

Instead he figures a way to convert dollars to bitcoins on the fly,  and the advice is to watch his back because the exchanges are going to shut him down.

Not sure I follow, can you clarify what you mean exactly? The 1.5 % are in and out, so that already includes using it for something, like let's say shopping at bitcoinstore.com . Or are you talking about turning Bridgewalker-USD into actual bills in your hand? Then yes, that will probably require an extra cash out step somewhere with additional fees. And that's a good point - I personally would consider this an interesting benchmark: Person starts with a $20 bill, turns that into Bitcoin, and a couple of weeks later pays some merchant and the merchant has X amount of USD in his pocket at the end. What is the fee for that complete cycle? If the user keeps bitcoins for the couple of weeks there is pretty much no telling what he ends up with - the market might have moved in his favor or against him. With Bridgewalker that uncertainty is taken out of the equation, for an additional 1.5 %. With fees for acquiring bitcoins and then fees the merchant is paying to convert it back, we probably can not beat credit cards at this point. But I would like to think that we can at some point, if we continue to optimize at all of these points.


I might release the Android client as open source at some point, but the server will probably stay closed source for the foreseeable future.


My thinking exactly! :-) And regarding that: Transfers between Bridgewalker users are instantaneous and free.


It's mostly a question of liquidity. If market spread is very large all of the time, you end up not getting the best price when moving in and out of Bitcoin which can increase that "round trip fee" quite a bit. That's why I started out with Mt.Gox USD market which is quite liquid. I would like to offer a Euro version in the near future.


At the moment your Bridgewalker account will always be denominated in USD, you can not change that. But in theory there could be a separate Euro version of Bridgewalker (and hopefully will be at some point) and then you could definitely exchange money between the two. It would use Bitcoin as the middle man: Bridgewalker-USD -> BTC -> Bridgewalker-EUR.


The Bridgewalker server is currently hosted in Germany.

I've got this installed, put in a small amount of BTC, and all appears good.  I'll be transferring money with someone else tomorrow.

The model seems incredibly dangerous because of volatility and slippage.

Very interesting idea. If this actually works with low fees and it's possible to get this to work elsewhere with other currencies than the dollar, it could be a killer app for a lot of things.

What are the methods for getting cash in and out?

You mean dangerous for the users? I am not sure I would call it "dangerous", but yes, the risk of slippage is assumed by the user. That's why the 1.5 % round trip fee is typical, not guaranteed. If you happen to use it in the middle of a crash you will probably end up paying more. That's why Bridgewalker always gives you an estimation on how high the currency conversion overhead is.

So as one of screenshots show, if I enter 5 USD, I see something like this: "Recipient will receive 0.10991995 BTC (~ 5.00 USD). From your account 5.03004 USD will be deducted. This is a difference of about 0.6 %". So in this case you paying 0.6 % more than the recipient will receive. And market spread is already taken into account here, because for the recipient a market order sell is assumed (albeit without any exchange fess the recipient might pay) and for you a market order buy for acquiring the bitcoins plus exchange fees is assumed. If there happens to be a much larger gap, you will see this percentage value going up and might want to wait for the markets to settle before doing your transaction. But in my testing over the last months this hasn't really been a problem for me.


Only Bitcoin.

why not using mtgox the polling data feed, it's super solid comparing to that shady streaming channel. The lag is unnoticeable most of the time.

The link to your forum profile is broken. You have it set to the logged in users profile.

For your profile specifically, you just need to append ";u=4070" at the end of "https://bitcointalk.org/index.php?action=profile".

I'm not sure if there's been much in the way of chargeback/attack security testing on the Giftcoins.me cards yet - but you might consider something along those lines (or just linking out to resellers) to provide initial and simple BTC acquisition for public users who want to explore the network and for whom a USD denominated account makes more sense.

You could even provide an in-app system for linking to bitcoin retailers (and probably derive some additional revenue that way) which would enable users quick access to the bitcoin marketplace. If they have a wallet on their phone with $xxx.xx USD in it and it is their primary or exclusive access point to the btc network they may find the fact that they can save hugely on bitcoinstore (for example) and only ever experience the transaction in USD (or at least have the USD price on every page of their transaction).

Yes, good point, I might have to do that, if all else fails. I would just prefer to have real-time updates. Mt.Gox seems to work on a new version of their Socket.IO server, maybe that will improve things.


Aw, thx for pointing that out, I will fix it in next update.


That's definitely something I find very interesting: Go into the next supermarket, buy a Bitcoin gift card denominated in USD ("$20 worth of bitcoins, for $20.25), load that up in Bridgewalker (with the added benefit of checking that you got your money's worth) and then spend it next door on cupcakes or on they other side of the globe on candy from Japan. And as mentioned before, I would consider it a goal to get that complete cycle down to 3 % and lower to be able to compete with credit cards. (At the moment I find all these "Bitcoin has low fees" claims a little bit dishonest. Yes, Bitcoin transactions themselves are fairly cheap, but pretty much anything practical you will do with Bitcoins _today_ will involve some currency conversion steps, which are unfortunately not cheap yet.)

And by the way: Anytime Bitcoin gift cards come up, some people want to have them denominated in BTC. While that seems natural, I don't see how it would be practical at all. A supermarket etc. can not reprice items in their inventory every few days. It needs to be a fixed price for the supermarket and then some extra activation step where the actual conversion at current market price happens. Giftcoins.me got that part right and it is a very interesting project.

Perhaps Expensify could recommend Bridgewalker to their clients' contractors:

http://techcrunch.com/2013/03/27/expensify-now-offers-support-for-bitcoin-an-alternative-to-paypal-for-international-contractors/

http://help.expensify.com/bitcoin/

So, iOS.   I understand your reluctance, what with Apple being the closed minded way they are, however..... Cydia ;)    There'd still be a decent market (in fact I'd suggest the people who are into Bitcoin at this "early" stage are the same who'd have a jailbroken phone).

Anyway, just food for thought.

My impression is, that almost nobody actually bothers to jailbreak their device, even among those people who would be able to do it. So I don't know, it seems to me like that would be a very limited group of people to whom that would be a solution. But I'll keep it in mind!

@BitPay: A new version of the app is out which now completes the support for URI links - i.e. it also works now, when clicking a link somewhere. So that means all "must have"s according to lovebitcoins.org (which, by the way, is down at the moment (?) ) are present. :-)

Quick update: I implemented a workaround to get rid of of the minimum limit of 0.01 BTC. Transactions down to 1 satoshi are now supported.

Version 0.4 of the app is out now and I have updated the website. I have slightly pivoted in how the idea and the service is presented. The new description reads like this:


Essentially I show your balance in BTC at all times to make it clear that this is really a Bitcoin wallet: Bitcoin in, Bitcoin balance, Bitcoin out. But that Bitcoin balance is adjusted up and down to create that "stable in respect to a counter currency" effect of the original Bridgewalker. It is really just a change in presentation, as the underlying system still works the same. But I'm hoping this presentation might make it easier for people to understand the value proposition and why such a service might be useful in some cases.

What do you guys think? I call it "exchange rate adjusted Bitcoin wallet" - does that term make sense to you? any better alternatives?

Discussion continues here: https://bitcointalk.org/index.php?topic=228535.0

Scratch that, discussion continues here. ;-)

I have quietly continued working on this, mostly fixing some smaller bugs and increasing stability and robustness of the software system. Some updates:

• I switched from USD to EUR as the counter currency for the time being. As I'm based in Germany and I wanted to focus more on in-person use cases, it makes it more practical for me to prototype it. Sorry to anyone who was relying on USD accounts! I hope to bring back USD and add other currencies at some point in the future.
• Uploaded an old presentation that I gave about green addresses (there called marker addresses): http://www.youtube.com/watch?v=1iLV9zjxHFU . Bridgewalker has support for green addresses, so deposits coming from recognized green addresses are credited instantaneously.
• I put together a video demonstrating the app. It is online at http://www.youtube.com/watch?v=ERVD1xoDT0M - although unfortunately already outdated again. =)
• Implemented preliminary backup functionality for guest accounts.

And Bridgewalker is now also on Twitter: https://www.twitter.com/bridgewalkerapp .

As always: Feedback and comments much appreciated! :-)

I presented Bridgewalker at the BitcoinKonferenz in Cologne on October 22. There is now a recording available: http://youtu.be/YWKkuQ__N7c . The talk is in German, but I added English subtitles (using YouTube's caption feature) and translated slides.

https://i.imgur.com/NlLi4uD.png

Hi everyone,

We are extremely pleased to announce the acquisition of Jan Vornberger's Bridgewalker wallet for Android (https://bitcointalk.org/index.php?topic=156943.0). We are also extremely pleased to announce that Jan will be joining the Hive (https://bitcointalk.org/index.php?topic=304060.0;all) team. Hive for Android will be available in late spring, 2014.

Wendell:


Jan:


Hive for Android's public repo will open in early January.

Discussion thread here:
https://bitcointalk.org/index.php?topic=334383

Bridgewalker is now open source! More info here: https://www.bridgewalkerapp.com/blog/2014/01/07/bridgewalker-open-source/ . Patches very welcome! :-)

May I ask the status of Bridgewalker now that MtGox has closed up shop?

I understand that it used MtGox to hold its reserves.

That's correct, unfortunately. I am traveling at the moment, but will give a more detailed update afterwards. Whatever happens though, all Bridgewalker users will be fully reimbursed. Sorry for the unavailability of the service at the moment.

It is with regret, that I have to announce, that I have decided to shut down Bridgewalker. With Mt.Gox ultimately imploding, I currently do not want to invest the effort to switch the backend to another exchange. I will write up a "post mortem" that will go into more details regarding my decision. All user funds will be refunded in full. I will announce a claim process for that in the coming days. Thanks to everyone who supported this project!

The claim process is now active. An update should be available shortly through Google Play which will allow you to submit a Bitcoin address, where you would like to have your funds sent.

More details in this blog post: https://www.bridgewalkerapp.com/blog/2014/03/14/bridgewalker-shutdown/ .

To end things on a positive note, I will now be completely focusing on Hive Android, which should be arriving shortly - keep an eye out for it! And who knows, maybe at some point Bridgewalker will be rising from its ashes. ;-) Thanks again to all beta users and everyone who helped me out along the way!