All About Authorize.Net’s Silent Post

One very common topic at the Authorize.Net developer forums is their Silent Post feature and how it works. In fact, how it works seems to be the most common question by far. For better or worse, Authorize.Net’s documentation seems to be limited concerning silent post so I decided to make this blog post summarizing the information that has been shared in the community concerning this feature.

When a transaction is completed (via SIM, AIM, ARB, or CIM), Authorize.Net’s servers will literally POST the details of the transaction to a URL you specify. In the server-side code for the page that the URL points to, you can read all of the transaction details as if they were fields on a form. The end user never sees any of this, it is all done server-to-server, thus the “Silent” part.

Silent post will be incurred for successful SIM, AIM, ARB, and CIM transactions (this includes declines) as well as virtual terminal transactions. However, if a credit card on file within an ARB subscription has expired a transaction will not process thus you will not receive a Silent Post response, as you only receive Silent Post responses to transactions that process through your account. In order to be notified about expired credit cards, you can enable the ARB email notifications from within the account control panel.

Silent Post responses are returned in real-time, meaning as soon as the transaction processes the Silent Post is sent to your specified URL.

To add or edit a Silent Post URL to your production environment account:

  1. Login to your Merchant Interface at
  2. Click Settings in the main left side menu
  3. Click Silent Post URL
  4. In the URL text field, enter the URL to which the payment gateway should copy the transaction relay response. This URL must start with either “http://” or “https://”
  5. Click Submit. A confirmation message indicates that the URL has been added

Processing A Silent Post

To receive and process Silent Post data all you really need to know is what fields to expect. Basically it reports the same information as an AIM transaction response but also includes the subscription ID and subscription transaction number for ARB subscriptions and CIM Profile ID for CIM transactions. See the AIM integration guide for details about the response codes.

Sample Silent Post

Below is a dump of the fields and sample data that can be sent from Silent Post:

[x_response_code] => 2
[x_response_subcode] => 1
[x_response_reason_code] => 2
[x_response_reason_text] => This transaction has been declined.
[x_auth_code] =>
[x_avs_code] => P
[x_trans_id] => 2692521494
[x_invoice_num] =>
[x_description] =>
[x_amount] => 5.99
[x_method] => CC
[x_type] => auth_capture
[x_cust_id] => 17234
[x_first_name] => Johnny
[x_last_name] => Fakeuser
[x_company] =>
[x_address] =>
[x_city] =>
[x_state] =>
[x_zip] =>
[x_country] =>
[x_phone] =>
[x_fax] =>
[x_email] =>
[x_ship_to_first_name] =>
[x_ship_to_last_name] =>
[x_ship_to_company] =>
[x_ship_to_address] =>
[x_ship_to_city] =>
[x_ship_to_state] =>
[x_ship_to_zip] =>
[x_ship_to_country] =>
[x_tax] => 0.0000
[x_duty] => 0.0000
[x_freight] => 0.0000
[x_tax_exempt] => FALSE
[x_po_num] =>
[x_MD5_Hash] => 35BB06A9F9349854922A13EE67AE5115
[x_cavv_response] =>
[x_test_request] => false
[x_subscription_id] => 4991817
[x_subscription_paynum] => 2
[x_cim_profile_id] => 12354

* x_subscription_paynum starts at 1 for the first payment

Reading The Data

If a transaction is approved x_response_code will contain a value of 1.

If the card is declined x_response_code will contain a value of 2.

If there was an error the card is expired x_response_code will contain a value of 3. Expired credit cards will have this response code and x_response_reason_code will contain a value of 8.

If the transaction is held for review x_response_code will contain a value of 4.

Testing A Silent Post Script

Testing a Silent Post script is easy to do as it is no different then handling a submitted form. All you need is sample data to work with. The form below submits a sample ARB transaction to a Silent Post processing script (that you will write):

<form action="" method="post">
    <input type="hidden" name="x_response_code" value="1"/>
    <input type="hidden" name="x_response_subcode" value="1"/>
    <input type="hidden" name="x_response_reason_code" value="1"/>
    <input type="hidden" name="x_response_reason_text" value="This 
                                                 transaction has been approved."/>
    <input type="hidden" name="x_auth_code" value=""/>
    <input type="hidden" name="x_avs_code" value="P"/>
    <input type="hidden" name="x_trans_id" value="1821199455"/>
    <input type="hidden" name="x_invoice_num" value=""/>
    <input type="hidden" name="x_description" value=""/>
    <input type="hidden" name="x_amount" value="9.95"/>
    <input type="hidden" name="x_method" value="CC"/>
    <input type="hidden" name="x_type" value="auth_capture"/>
    <input type="hidden" name="x_cust_id" value="1"/>
    <input type="hidden" name="x_first_name" value="John"/>
    <input type="hidden" name="x_last_name" value="Smith"/>
    <input type="hidden" name="x_company" value=""/>
    <input type="hidden" name="x_address" value=""/>
    <input type="hidden" name="x_city" value=""/>
    <input type="hidden" name="x_state" value=""/>
    <input type="hidden" name="x_zip" value=""/>
    <input type="hidden" name="x_country" value=""/>
    <input type="hidden" name="x_phone" value=""/>
    <input type="hidden" name="x_fax" value=""/>
    <input type="hidden" name="x_email" value=""/>
    <input type="hidden" name="x_ship_to_first_name" value=""/>
    <input type="hidden" name="x_ship_to_last_name" value=""/>
    <input type="hidden" name="x_ship_to_company" value=""/>
    <input type="hidden" name="x_ship_to_address" value=""/>
    <input type="hidden" name="x_ship_to_city" value=""/>
    <input type="hidden" name="x_ship_to_state" value=""/>
    <input type="hidden" name="x_ship_to_zip" value=""/>
    <input type="hidden" name="x_ship_to_country" value=""/>
    <input type="hidden" name="x_tax" value="0.0000"/>
    <input type="hidden" name="x_duty" value="0.0000"/>
    <input type="hidden" name="x_freight" value="0.0000"/>
    <input type="hidden" name="x_tax_exempt" value="FALSE"/>
    <input type="hidden" name="x_po_num" value=""/>
    <input type="hidden" name="x_MD5_Hash" value="A375D35004547A91EE3B7AFA40B1E727"/>
    <input type="hidden" name="x_cavv_response" value=""/>
    <input type="hidden" name="x_test_request" value="false"/>
    <input type="hidden" name="x_subscription_id" value="365314"/>
    <input type="hidden" name="x_subscription_paynum" value="1"/>
    <input type="submit"/>

If you’re looking for PHP code for processing a Silent Post check out Handling Authorize.Net ARB Subscription Failures at my Merchant Account Services blog.

Related Posts:

36 thoughts on “All About Authorize.Net’s Silent Post

  1. Pingback: » Handling Authorize.Net ARB Subscription Failures - Merchant Account Services Blog

  2. thanks for providing a 101 on silentPost .

    We are working on a large PCI Compliance project in house. In our systems, in order to reconcile our credit card transactions, we need to get the card type returned in the Silent Post. From the AIM guide and the site documentaion, I see that Crad type is not being returned in the silentPost.
    There are no automted reports that we can dopwnlod from that would give us this information.

    Can you throw some light on why the card type is not included in the Silent Post and whether or not there are plans to include it in a upcoming release.

    Thanks for your help.

  3. Gary, it is probably not included because it can be, and should be, recorded at the time the credit card is accepted by a website/software. It also doesn’t really have anything to do with individual transactions being processed so reporting it through silent post would be out of silent post’s scope. I haven’t heard if they plan on including it in silent post but I doubt it is in Authorize.Net’s plans.

  4. thanks for your quick repsonse.

    If we are using’s Payment submission form then we dont have control of what card type the customer chooses while making the payment.
    so the Card type that the customer chooses while making the payment might be different from what was recorded in our systems.

    makes sense?

  5. Ah, if you’re using SIM you lose a lot of control over the checkout process. Maybe this is a good reason to switch to AIM?

  6. We are implementing direct Customer Payments and automated recurring billing payments.
    For the customer paying directly AIM may be an option, but for the subscription type payment services, we DO NEED to rely on the Silent Post and hence the need for the card type.

    Is there any work around that can be used to get the card type through silent post?
    or can we use AIM and SIM interchangeably depending on the transaction (direct/subscription based) ?

  7. If it is a subscription you should already know the card type since you had to have the credit card number to set up the subscription (at least you do through their ARB API). Naturally each payment will use the same card so all you have to do is retrieve the card type from your database when a silent post is made using their subscription ID (which is provided when their subscription is created and through silent post). AIM transactions require your system handling the credit card information at the time of payment so that also allows you to capture the card type for later retrieval as well.

    Basically what it boils down to is if you didn’t or are unable to capture the card type at the time the payment is made or subscription is created there is no way to retrieve it through silent post later.

  8. Thanks for the detailed response.
    we will be evaluating our requirements and the options we have before deciding which method (AIM/SIM ) to use.

  9. First of all, you are awesome and a total lifesaver. You have saved me hours of frustration tonight.

    I have two questions and I would love to hear your thoughts if you would be so kind:

    1. I have silent posts coming in from both AIM and ARB transactions. Using the MD5 to verify that the ARB transactions are legitimate is easy. But, for AIM transactions I can’t find any info on using MD5 at all. In fact, says that MD5 “is not necessary for use with AIM” (here: Is there any info anywhere about using MD5 to verify that a silent post about an AIM transaction is indeed coming from

    2. Let’s say I have an ARB subscriber whose first payment works without issue, but then their card is declined when their second payment is attempted (and I cut off their access to my site). Two days later, they update their credit card info to a legitimate card and I update the ARB subscription and reactivate their access to my site. My question is this: does that missed payment ever actually get charged? Does ARB know to go back and try again for the missed payment after the card is updated, or did my customer just get a free month?

    Thank you so much for any help you can provide. The lack of documentation on this stuff is extremely frustrating and you are a beacon of hope!


  10. Bob,

    I’m glad you found this information helpful. That’s why I post it. ๐Ÿ™‚

    1. What’s interesting about the MD5 field is a value is returned from Authnet for AIM and ARB transactions. It would be cool if they would tell us how they create it so we could use it to verify the transaction.

    Your options would be to either use the customer ID or invoice number to pull the customer information out of the database and verify it against what is submitted via silent post. Or, if you’re not using the description field for anything else, put in your own MD5 hash in there and use it just like it was a SIM transaction.

    2. If a card is declined ARB will not go back and charge the payment. This means you’ll have to do it yourself. But that isn’t a big deal since, assuming you have a form your customers fill out to provide their updated credit card information, you can use AIM at the time they update their credit card info to process any back payments they owe.

  11. I am using the ARB method for, I have used your sample code in php to get silent post responses from But the issue is I am not getting the subscription Id from silent post url.

    Please help

    Thanks in advance

  12. John, excellent website, you’ve made this ARB thing almost easy! Thank you so much for putting this information together! I have a question about expired credit cards…

    In your document, you said:

    However, if a credit card on file within an ARB subscription has expired a transaction will not process thus you will not receive a Silent Post response, as you only receive Silent Post responses to transactions that process through your account. In order to be notified about expired credit cards, you can enable the ARB email notifications from within the account control panel.

    But later on, you also said:

    If there was an error the card is expired x_response_code will contain a value of 3. Expired credit cards will have this response code and x_response_reason_code will contain a value of 8.

    So what really happens when a credit card with a subscription expires?

  13. Authorize.Net says expired cards will not be sent to Silent Post. But I see plenty of these sent to Silent Post. I am not sure whether all expired cards are sent to Silent Post, or just the ones where the wrong expiration date was provided to Authorize.Net and they found out it was expired when processing the transaction. But you will see expired transactions sent to Silent Post so it’s best to be aware of them and handle them accordingly.

  14. Hi Johnny,

    I have run into a problem using the Silent Post with SIM and I’m hoping that you can provide some insight in how to solve the problem.

    Here is the background:
    I’ve built three separate .NET web pages using SIM to process the credit card transactions for our company store, our membership department, and our donations department.

    For the company store, I’m using SIM and receiving the Silent Post transaction information without a problem. The company store has its own account.

    For the membership department, I am using Simple Checkout buttons in .NET web pages and also using SIM. I receive the silent post transaction information without a problem for the membership department. The membership department shares its account and the silent post page with the donations department.

    Here is the problem:
    I am not receiving Silent Post information for the donations department who is sharing an account and the silent post page with the membership department. I am using a .NET web page and SIM to process
    the donations department information.

    Besides writing the information to a database, I have the silent post page set to write to a text file whenever the page is queried. I have verified that
    information will print to the text file even if the silent post data is empty. The problem is that the transactions from the donations department don’t appear to be sent to the Silent Post page from

    I’ve talked to support but they can’t provide any guidance as to why the Silent post data from the membership department transactions aren’t reaching the silent post page.

    Do you have any suggestions on what might be causing the Silent Post to fail for the donations department web page?

    Thank you for the wonderful resource that you provide.

  15. John,

    Your code is great and many thanks.

    Are these the only fields output to the silent post? Specifically I am looking for the subscription name in ARB’s.


  16. I have set up the silent post URL, it’s getting called but not capturing any information, any idea what could be the issue?

  17. Hey john,
    I have set up the silent post URL, itโ€™s getting called but not capturing any post response information, any idea what could be the issue?

  18. Hi,
    This is great resource about Silent post, I have a question to ask.

    If a site administrator went straight into his account and cancel a subscription, would it trigger a silentpost call back for subscription cancellation?

    Thanks in advance.


  19. No, it would not. Silent Post only receives data from transactions. Cancelling a subscription wouldn’t be considered a transaction.

  20. Hi John frist of all thank you very much becouse your information is the better I found in internet about it. Just a question. Silent Post, sends me a post message every time there is a change on the payment status (x_response_code), I mean if for example I do an authorize buying, and at the end of this buying, I get payment_status Pending, is Silent post going to notify me if a day later this status changes to denied?? Thank you very much!

  21. Your blog is nice but I am still facing problems.

    I am going ARB using silent post.

    As of now I can see that my create subscription step is returning success message but the transaction remain in “Captured/Pending Settlement” for a long time and never hit back silent post URL.

    Please suggest.

  22. Hi John. I was VERY happy to see in your post that one of the values that might be sent in the silent post was:

    [x_cim_profile_id] => 12354

    However, after I ran a live transaction using the CIM api, no such value was found in the silent post.

    Do you have any additional information about that? Is it a field that was previously sent but is no longer being sent? I would be EXTREMELY appreciative for any additional info you can share on that.

    What I’m trying to do is outsource ALL credit card handling for PCI Compliance reasons. I found a provider which can provide a hosted payment page (in their PCI compliant environment) which will look identical to mine. They customer enter the information on that page and after processing, the customer is sent back to my site. This works great but that provider doesn’t send me CIM ids!

    So that’s why i was so excited to see in this post that the CIM id would be sent in the silent post. I could then use the API to match up the last 4 digits of the card used with the one in the pmt profile. However, as I said, I’m not receiving that value in the silent post.

    Again, I would be VERY appreciate of any additional info you can share on that ‘[x_cim_profile_id] => 12354’ field which according to this article should be sent in silent post.

    And thanks for sharing all this great info!

    : )
    John G

  23. Hello Sir

    Can you tell me that whenever the subscription in is renewed then silent post notify us or not?


  24. You should highlight that does not use a useragent. If you use a application firewall (for PCI purposes), you may need to disable any filters having to do with blocking requests from users with empty user agents.

  25. I now have to recommend against relying on silentPosts to determine if a transaction occurred. Instead you should query for transactions using the transaction details API

    We use silent posts to track when ARB transaction succeed or fail. On a certain day we did not receive silent posts from even though transactions occurred. I have checked our logs, the server was up and responsive at the time when the transactions were processed. When I contacted for more information they could provide nothing except “we don’t see any error messages/codes”.

    I learned two things from the supervisor I talked to:
    1) does not check response codes for their silentPosts
    2) does not log anything for silentPosts

    This means that silentPost is not reliable (and hence, should not be used).

  26. I have automated processes that are dependent upon the postback in order for online subscriptions to be renewed. It’s lame that the SilentPost service isn’t more robust and at least logging HTTP status codes and/or the first thousand or so bytes of the response.

    Thanks for sharing and I’ll definitely going to review the XML method since their no official ColdFusion SDK available.

  27. Only wanna tell that this is very useful , Thanks for taking your time to write this. Santerre

  28. Hello,

    If we simply store an arb silent post received from, we see a field x_account_number, which contains the last four digits of the credit card. says that it is included in all AIM transactions. Why it is not included here?

  29. James is absolutely correct. We have been relying on Silent Post to communicate ARB transactions. And on days where many transactions are processed (1st month, the 15th, ect) we end of losing some. In our case, this becomes like searching for a needle in a haystack as we process thousands of transactions and there is no easy way to export out the valid ones from Auth and bump it up against our Silent Post list. Bottom line – if you rely on Silent Post to sync your transactions, you are asking for big trouble.

  30. I think that silent post is not working if url provided is not at standard http(80) or https(443) port. Same as for relay response.
    It is never mentioned by, and therefore it could be very frustrating to make it work.

Leave a Reply

Your email address will not be published. Required fields are marked *