
Show HN: Coinwall, a bitcoin paywall - marcell
http://www.coinwall.co
======
bobbygoodlatte
Very cool. One idea you might play with is the idea of debt. In other words:
allow me to view the content for free a couple times, while racking up an
"IOU".

Perhaps after the debt accumulates I'm forced to pay my freeloader's bill to
continue seeing content.

Second: Go to where the users are. You should have Coinbase support.

Looking forward to watching where you take this :)

~~~
marcell
Re IOU system: that is an interesting idea! It would solve one of the big
problems with micropayments, which is the mental barrier. Thanks.

Re Coinbase support: point taken; they are indeed one of the most popular
wallets.

------
dijxtra
Excellent concept... but I could not use it. It says "To view 46 words of
content, send exactly 0.00015612 BTC ($0.10) to
12smAWhdY9aMFyEenX6NLVZDend5WJgfVc". I paid with this transaction:
[https://blockchain.info/tx/047a379b7530f98876818540356b66964...](https://blockchain.info/tx/047a379b7530f98876818540356b66964534d00115553a78845d41ba390e5e84)
And nothing happened, not even after 2 confirmations.

~~~
rarestblog
Yes, excellent concept, but also did not work for me. Also attempt to refresh
the page asks for another payment. In this moment of weakness you wish there
was a "refund" button on BitCoin :)

~~~
marcell
Do you happen to have the transaction ID on hand for the failed payment?

Also, if you have a refund address, I can send the BTC back. It is a small
amount, but still :)

------
rolleiflex
"Coinwall is a zero-friction paywall that uses bitcoin."

A little bit ironic. Isn't paywall itself friction?

~~~
StavrosK
Given that you need the paywall, there's no _additional_ friction. By that
logic, doing _anything_ is friction, compared to not doing it. Why breathe?

------
krrishd
A friend of mine, Zach Latta made something very similar and posted to HN a
while ago:
[https://news.ycombinator.com/item?id=6881757](https://news.ycombinator.com/item?id=6881757)

------
jasonzemos
I'm assuming the technology behind this is either of two things:

* An implementation of probabilistic nanopayments ([https://en.bitcoin.it/wiki/Nanopayments](https://en.bitcoin.it/wiki/Nanopayments))

* Massive amount of extremely small transactions.

I'd like to know if any consideration has been made for the amount of data
hitting the blockchain when this scales. A flood of transactions will cause
fees to rise higher than the principal payment.

------
gbl08ma
I built something like this into my URL shortener a long time ago (
[http://tny.im/toll.php](http://tny.im/toll.php) ). However, it is nowhere as
easy to use, uses the Blockchain.info wallet APIs in a way they were never
meant to be used, doesn't have automatic (nor automated) payouts and I'm not
even sure that it still works. I never really advertised it seriously. Since
nobody ever really used it, and because it's not the main purpose of the
service (it has enough feature creep already...), I am considering
discontinuating the feature.

If Coinwall becomes popular (and I hope it does) I'll be damned :)

------
adrianwaj
Cool. Good for Soundcloud or YT users that want to provide links to dl their
content for a fee without requiring too much hoop-jumping. Even a way of
locating some content just through the referral link would be nice... that way
a user on their SC and YT pages can set a permalink, but provide the
redirection addresses on coinwall. Or rather, coinwall could have a
"Soundcloud/YT" referral url that the user fills in when setting up the
download: it's preprogrammed to handle those referrals and even stats could be
given on the download page and the site could offer top-10 lists of music and
video.

~~~
marcell
Yea, I was thinking of adding file upload support for music/videos is a next
feature. Having support for Soundcloud/Youtube/etc. URLs is a neat idea and
would make for an easy UX.

~~~
adrianwaj
Another idea is to have a "set your own price" w/wo a minimum price, like with
Bandcamp, where the download is like a post-donation gift. Also, once paid,
the purchaser may want to be able to leave an email address or message to get
further discounts in the future from the artist as VIP fans.

------
cr3ative
Ah. It seems to link directly to the protocol address "bitcoin:" \- and I
don't have anything registered to pick up on that - making the button appear
completely broken for me.

~~~
glitch003
You should get a bitcoin client :)

------
jacques_chester
Very clever. However I still think that any scheme that requires people to pay
in advance is going to struggle. You're always going to be facing the
"simulation heuristic".

------
tinypass
Tinypass is another paywall service that accepts bitcoin payments.
[http://tinypass.com](http://tinypass.com)

------
jordanthoms
Unfortunately bitcoin's potential for micropayments isn't so great at the
moment, when the transaction fee is 5-10c.

~~~
marcell
It was lowered by 10x recently, to .5-.1c:
[https://github.com/bitcoin/bitcoin/pull/3305](https://github.com/bitcoin/bitcoin/pull/3305)

~~~
nwh
It really hasn't been lowered. Most users aren't running the latest code, so
you would struggle to ever get your transaction into a block that way.

------
udfalkso
Great concept. Experience still needs some work...

How does the verification work? Do I have to register to verify that I've
paid?

~~~
marcell
No registration is required to pay or to make a paywall.

Verification is done by assigning a slightly different payment amount to each
person. For example, if you are charging 0.00015 BTC, the amount 0.00015001
and 0.00015002 may be used to distinguish two payments. These amounts are
cycled every ~15 mins.

Edit: Also, I may add support for BIP32 master public keys in the future. This
would allow derivation of child public keys on behalf of the user, providing a
unique payment address for each transaction. This is technically easy to do,
the only problem is most people don't know how to access their master public
key.

~~~
Rygu
That is kind of confusing isn't it, because there's also a miner fee. Does
your algorithm know how to subtract the miner fee to get the unique amount?
Also, are your floating point operations (subtract, compare) done correctly?

[http://floating-point-gui.de/errors/comparison/](http://floating-point-
gui.de/errors/comparison/)

~~~
bowmessage
Anyone who uses floating point numbers in a bitcoin project is doing it wrong.
Bitcoins have a fixed (for now) level of precision. 1 satoshi is currently the
smallest discrete amount of bitcoin that can exist.

The miner's fee is separate from the amount sent, this is easy to distinguish.

------
slipstream-
Any chance of dogecoin support? Given their community thrives on
micropayments...

------
christiangenco
Ooo, I like this concept.

