diff --git a/app/models/user.rb b/app/models/user.rb
index 32093a87b..21351d6fc 100644
--- a/app/models/user.rb
+++ b/app/models/user.rb
@@ -83,6 +83,14 @@ class User < ApplicationRecord
     invalid_editor_version: "%<value>s must be either v1 or v2",
     reserved_username: "username is reserved"
   }.freeze
+  # follow the syntax in https://interledger.org/rfcs/0026-payment-pointers/#payment-pointer-syntax
+  PAYMENT_POINTER_REGEXP = %r{
+    \A                # start
+    \$                # starts with a dollar sign
+    ([a-zA-Z0-9\-.])+ # matches the hostname (ex ilp.uphold.com)
+    (/[\x20-\x7F]+)?  # optional forward slash and identifier with printable ASCII characters
+    \z
+  }x.freeze
 
   attr_accessor :scholar_email, :new_note, :note_for_current_role, :user_status, :pro, :merge_user_id,
                 :add_credits, :remove_credits, :add_org_credits, :remove_org_credits, :ip_address
@@ -205,6 +213,7 @@ class User < ApplicationRecord
   validates :inbox_type, inclusion: { in: INBOXES }
   validates :name, length: { in: 1..100 }
   validates :password, length: { in: 8..100 }, allow_nil: true
+  validates :payment_pointer, format: PAYMENT_POINTER_REGEXP, allow_nil: true
   validates :rating_votes_count, presence: true
   validates :reactions_count, presence: true
   validates :sign_in_count, presence: true
@@ -252,6 +261,7 @@ class User < ApplicationRecord
   # make sure usernames are not empty, to be able to use the database unique index
   before_validation :verify_email
   before_validation :set_username
+  before_validation :strip_payment_pointer
   before_create :set_default_language
   before_destroy :unsubscribe_from_newsletters, prepend: true
   before_destroy :destroy_follows, prepend: true
@@ -669,4 +679,8 @@ class User < ApplicationRecord
 
     errors.add(:password, "doesn't match password confirmation")
   end
+
+  def strip_payment_pointer
+    self.payment_pointer = payment_pointer.strip if payment_pointer
+  end
 end
diff --git a/spec/models/user_spec.rb b/spec/models/user_spec.rb
index 367458c9f..1f960cb76 100644
--- a/spec/models/user_spec.rb
+++ b/spec/models/user_spec.rb
@@ -187,6 +187,11 @@ RSpec.describe User, type: :model do
       it { is_expected.not_to allow_value("AcMe_1%").for(:username) }
       it { is_expected.to allow_value("AcMe_1").for(:username) }
 
+      it { is_expected.not_to allow_value("$example.com/value\x1F").for(:payment_pointer) }
+      it { is_expected.not_to allow_value("example.com/value").for(:payment_pointer) }
+      it { is_expected.to allow_value(" $example.com/value ").for(:payment_pointer) }
+      it { is_expected.to allow_value(nil).for(:payment_pointer) }
+
       it { is_expected.to validate_inclusion_of(:inbox_type).in_array(%w[open private]) }
 
       it { is_expected.to validate_length_of(:email).is_at_most(50).allow_nil }
diff --git a/spec/system/user/user_edits_extensions_spec.rb b/spec/system/user/user_edits_extensions_spec.rb
index 72af98f94..7d3893947 100644
--- a/spec/system/user/user_edits_extensions_spec.rb
+++ b/spec/system/user/user_edits_extensions_spec.rb
@@ -53,4 +53,17 @@ RSpec.describe "User edits their extensions", type: :system, js: true do
       expect(page).to have_text("Feed url is not a valid RSS/Atom feed")
     end
   end
+
+  describe "PaymentPointer" do
+    before do
+      visit user_settings_path(:extensions)
+    end
+
+    it "fails if the payment pointer is invalid" do
+      fill_in "user[payment_pointer]", with: "invalid_example/value"
+      click_on "Save Web Monetization Settings"
+
+      expect(page).to have_text("Payment pointer is invalid")
+    end
+  end
 end