# Interface Between the BlockCerts App and the Issuer URL **URL:** \ **Category:** Technical\ **Created:** [July 17, 2018, 5:31pm UTC](https://community.blockcerts.org/t/interface-between-the-blockcerts-app-and-the-issuer-url/1201 "2018-07-17T17:31:34Z")\ **Posts on this page:** 9\ **Page:** 1
**Author:** ![dev](https://avatars.discourse-cdn.com/v4/letter/d/e8c25b/32.png) [@dev](https://community.blockcerts.org/u/dev)\ **Post date:** [July 17, 2018, 5:31pm UTC](https://community.blockcerts.org/t/interface-between-the-blockcerts-app-and-the-issuer-url/1201/1 "2018-07-17T17:31:35Z")
We are trying to build a demo of the entire process of blockchain based certification using the Blockcerts app. We have been able to issue certificates and successfully get it verified using the cert-issuer and web based verifier . Now, we are trying to interface the Blockcerts app with our server, so that the User can add us as a Issuer and get our issued certificates on their Blockcerts app. We are unsure how to do this in terms of setting up our server to communicate with the app. By reading from the discussions here, it seems that the app will call the Issuer URL that the user provides, with the public address of the user. We are unsure how to receive this call on our server and what should be the feedback (content and format) that the server needs to send back to the app. Can someone help us out with this and/or point us to some documentation/discussion that makes this point clear? ---
**Author:** ![stuartf](https://sea2.discourse-cdn.com/flex016/user_avatar/community.blockcerts.org/stuartf/32/39_2.png) [@stuartf](https://community.blockcerts.org/u/stuartf)\ **Post date:** [July 18, 2018, 5:14pm UTC](https://community.blockcerts.org/t/interface-between-the-blockcerts-app-and-the-issuer-url/1201/2 "2018-07-18T17:14:48Z")
I found this post: [Learning Machine Contributes Android App to Blockcerts](https://community.blockcerts.org/t/learning-machine-contributes-android-app-to-blockcerts/227/12) it looks like we need to respond with JSON like what’s at [https://github.com/blockchain-certificates/BlockcertsFramework-iOS/blob/master/Frameworks/BlockcertsTests/Resources/Issuers/issuer-v2.json](https://github.com/blockchain-certificates/BlockcertsFramework-iOS/blob/master/Frameworks/BlockcertsTests/Resources/Issuers/issuer-v2.json) but with our issuer details obviously. ---
**Author:** ![dev](https://avatars.discourse-cdn.com/v4/letter/d/e8c25b/32.png) [@dev](https://community.blockcerts.org/u/dev)\ **Post date:** [July 18, 2018, 10:33pm UTC](https://community.blockcerts.org/t/interface-between-the-blockcerts-app-and-the-issuer-url/1201/3 "2018-07-18T22:33:19Z")
Cool. Thanks @stuartf. Do you know how to receive this HTTP call on the issuer side? so as to grab the Public Address of the user that is supposed to be present on the http call payload? ---
**Author:** ![stuartf](https://sea2.discourse-cdn.com/flex016/user_avatar/community.blockcerts.org/stuartf/32/39_2.png) [@stuartf](https://community.blockcerts.org/u/stuartf)\ **Post date:** [July 19, 2018, 11:31am UTC](https://community.blockcerts.org/t/interface-between-the-blockcerts-app-and-the-issuer-url/1201/4 "2018-07-19T11:31:18Z")
I think that first request is just a GET without any parameters. Then I think it will POST with the user’s public key and an optional one time shared token to the introductionUrl from the issuer details. ---
**Author:** ![dev](https://avatars.discourse-cdn.com/v4/letter/d/e8c25b/32.png) [@dev](https://community.blockcerts.org/u/dev)\ **Post date:** [July 19, 2018, 9:17pm UTC](https://community.blockcerts.org/t/interface-between-the-blockcerts-app-and-the-issuer-url/1201/5 "2018-07-19T21:17:10Z")
Thanks! Was able to track the POST request from the app. Looks like this. print request.data {“bitcoinAddress”:“xxxxxxxxxxxx”,“nonce”:“yyyyyy”} Its public address for a bitcoin wallet. I was looking to get the whole demo working on Ethereum chain… ---
**Author:** ![aronning](https://avatars.discourse-cdn.com/v4/letter/a/47e85d/32.png) [@aronning](https://community.blockcerts.org/u/aronning)\ **Post date:** [July 20, 2018, 2:29pm UTC](https://community.blockcerts.org/t/interface-between-the-blockcerts-app-and-the-issuer-url/1201/6 "2018-07-20T14:29:33Z")
Address from the mobile app is primarily for signing keys. It could be any sort of priv/pub key and it would work just the same. With our current implementation, there’s no need to have this be chain specific, especially since transactions are not sent to the recipients anyways, only referenced inside the blockcert. FYI, since you’re going down that pathway right now, I have to mention that Ethereum verification inside the mobile app is currently in the works. So you’ll be able to import the certificate but not verify yet. ---
**Author:** ![dev](https://avatars.discourse-cdn.com/v4/letter/d/e8c25b/32.png) [@dev](https://community.blockcerts.org/u/dev)\ **Post date:** [July 20, 2018, 2:51pm UTC](https://community.blockcerts.org/t/interface-between-the-blockcerts-app-and-the-issuer-url/1201/7 "2018-07-20T14:51:06Z")
Thanks @aronning Okays. Yes, knew that the transactions are sent to a burn address. So, This pub key would be unique to the particular user. That would be enough as an identity for the user. Cool, We will use this public address for issuing the blockcert. And, thanks for the verification on the mobile app info. This was going to be my upcoming post on the forum 🙂 , as I saw yesterday that verification was not initiating on the app. ---
**Author:** ![aronning](https://avatars.discourse-cdn.com/v4/letter/a/47e85d/32.png) [@aronning](https://community.blockcerts.org/u/aronning)\ **Post date:** [July 20, 2018, 2:53pm UTC](https://community.blockcerts.org/t/interface-between-the-blockcerts-app-and-the-issuer-url/1201/8 "2018-07-20T14:53:36Z")
Yup, each blockcerts app is essentially a wallet with that regards. Right now they don’t do a whole lot, but we’ve talked about some cool functionality that would rely on those addresses/signatures 🙂 ---
**Author:** ![dev](https://avatars.discourse-cdn.com/v4/letter/d/e8c25b/32.png) [@dev](https://community.blockcerts.org/u/dev)\ **Post date:** [July 20, 2018, 3:03pm UTC](https://community.blockcerts.org/t/interface-between-the-blockcerts-app-and-the-issuer-url/1201/9 "2018-07-20T15:03:24Z")
More cooler functionality with the app… Looking forward to that!!