diff --git a/zip-0321.rst b/zip-0321.rst
index 3859af3e..40f7f00a 100644
--- a/zip-0321.rst
+++ b/zip-0321.rst
@@ -88,7 +88,7 @@ URI Syntax:
   addrparam       = "address" [ paramindex ] "=" zcashaddress
   amountparam     = "amount"  [ paramindex ] "=" 1*DIGIT [ "." 1*DIGIT ]
   labelparam      = "label"   [ paramindex ] "=" *qchar
-  memoparam       = "memo"    [ paramindex ] "=" *qchar
+  memoparam       = "memo"    [ paramindex ] "=" *base64url
   messageparam    = "message" [ paramindex ] "=" *qchar
   paramname       = ALPHA *( ALPHA / DIGIT / "+" / "-" )
   reqparam        = "req-" paramname [ paramindex ] [ "=" *qchar ]
@@ -97,7 +97,8 @@ URI Syntax:
   allowed-delims  = "!" / "$" / "'" / "(" / ")" / "*" / "+" / "," / ";"
 
 Here, ``ALPHA``, ``unreserved`` and ``pct-encoded`` are as defined in
-[#RFC3986]_. "base58" is defined as in [#base58check]_
+[#RFC3986]_. "base58" is defined as in [#base58check]_. "base64url" is defined
+as in [#base64url]_ with padding omitted.
    
 A ZIP-321 URI represents a request for the construction of a transaction having
 one or more *payments*. In the case that only a single payment is being
@@ -152,6 +153,40 @@ message
    Message that clients can display for the purpose of presenting descriptive
    information about the transaction to the user.
 
+Examples
+--------
+
+Valid examples
+~~~~~~~~~~~~~~
+
+.. code-block:: 
+
+  zcash:ztestsapling10yy2ex5dcqkclhc7z7yrnjq2z6feyjad56ptwlfgmy77dmaqqrl9gyhprdx59qgmsnyfska2kez?amount=1&memo=VGhpcyBpcyBhIHNpbXBsZSBtZW1vLg&message=Thank%20you%20for%20your%20purchase
+
+A valid payment request for a payment of 1 ZEC to a single shielded address, with a base64url-encoded memo and a message for display by the wallet.
+
+.. code-block:: 
+
+  zcash:?address=tmEZhbWHTpdKMw5it8YDspUXSMGQyFwovpU&amount=123.456&memo=eyAia2V5IjogIlRoaXMgaXMgYSBKU09OLXN0cnVjdHVyZWQgbWVtby4iIH0&address.1=ztestsapling10yy2ex5dcqkclhc7z7yrnjq2z6feyjad56ptwlfgmy77dmaqqrl9gyhprdx59qgmsnyfska2kez&amount.1=0.789&memo.1=VGhpcyBpcyBhIHVuaWNvZGUgbWVtbyDinKjwn6aE8J-PhvCfjok
+
+A valid payment request with one transparent and one shielded recipient address, with encoded JSON and unicode memos.
+
+Invalid Examples
+~~~~~~~~~~~~~~~~
+
+.. code-block:: 
+
+  zcash:?amount=3491405.05201255&address.1=ztestsapling10yy2ex5dcqkclhc7z7yrnjq2z6feyjad56ptwlfgmy77dmaqqrl9gyhprdx59qgmsnyfska2kez&amount.1=5740296.87793245
+
+An invalid payment request; this is missing a payment address for the 0th payment index..
+
+.. code-block:: 
+
+  zcash:?address=tmEZhbWHTpdKMw5it8YDspUXSMGQyFwovpU&amount=1&address=ztestsapling10yy2ex5dcqkclhc7z7yrnjq2z6feyjad56ptwlfgmy77dmaqqrl9gyhprdx59qgmsnyfska2kez&amount.1=2
+  zcash:?address.1=tmEZhbWHTpdKMw5it8YDspUXSMGQyFwovpU&amount=1&address.0=ztestsapling10yy2ex5dcqkclhc7z7yrnjq2z6feyjad56ptwlfgmy77dmaqqrl9gyhprdx59qgmsnyfska2kez&amount.1=2
+
+Invalid payment requests; this contains more than one value for the 0th and 1st payment addresses, respectively.
+
 Forward compatibility
 ---------------------
 
@@ -179,3 +214,4 @@ References
 .. [#bip-0021] `BIP 21: URI Scheme <https://github.com/bitcoin/bips/blob/master/bip-0021.mediawiki>`_
 .. [#bip-0070] `BIP 70: Payment Protocol <https://github.com/bitcoin/bips/blob/master/bip-0070.mediawiki>`_
 .. [#base58check] `Base58Check encoding <https://en.bitcoin.it/wiki/Base58Check_encoding>`_
+.. [#base64url] `RFC 4648 section 5: Base64 Encoding with URL and Filename Safe Alphabet <https://tools.ietf.org/html/rfc4648#section-5>`_