diff --git a/corporate/tests/stripe_fixtures/attach_discount_to_realm:Charge.list.1.json b/corporate/tests/stripe_fixtures/attach_discount_to_realm:Charge.list.1.json
new file mode 100644
index 0000000000..c6837caf84
--- /dev/null
+++ b/corporate/tests/stripe_fixtures/attach_discount_to_realm:Charge.list.1.json
@@ -0,0 +1,76 @@
+{
+  "data": [
+    {
+      "amount": 9600,
+      "amount_refunded": 0,
+      "application": null,
+      "application_fee": null,
+      "balance_transaction": "txn_1DasKCGh0CmXqmnwGpFYo8WR",
+      "captured": true,
+      "created": 1543270384,
+      "currency": "usd",
+      "customer": "cus_NORMALIZED0001",
+      "description": null,
+      "destination": null,
+      "dispute": null,
+      "failure_code": null,
+      "failure_message": null,
+      "fraud_details": {},
+      "id": "ch_1DasKCGh0CmXqmnwR0PdCeDM",
+      "invoice": "in_1DasKCGh0CmXqmnw6gIFvxxy",
+      "livemode": false,
+      "metadata": {},
+      "object": "charge",
+      "on_behalf_of": null,
+      "order": null,
+      "outcome": {
+        "network_status": "approved_by_network",
+        "reason": null,
+        "risk_level": "normal",
+        "risk_score": 1,
+        "seller_message": "Payment complete.",
+        "type": "authorized"
+      },
+      "paid": true,
+      "payment_intent": null,
+      "receipt_email": "hamlet@zulip.com",
+      "receipt_number": null,
+      "refunded": false,
+      "refunds": {},
+      "review": null,
+      "shipping": null,
+      "source": {
+        "address_city": "Pacific",
+        "address_country": "United States",
+        "address_line1": "Under the sea,",
+        "address_line1_check": "pass",
+        "address_line2": null,
+        "address_state": null,
+        "address_zip": "33333",
+        "address_zip_check": "pass",
+        "brand": "Visa",
+        "country": "US",
+        "customer": "cus_NORMALIZED0001",
+        "cvc_check": null,
+        "dynamic_last4": null,
+        "exp_month": 3,
+        "exp_year": 2033,
+        "fingerprint": "NORMALIZED000001",
+        "funding": "credit",
+        "id": "card_NORMALIZED00000000000001",
+        "last4": "4242",
+        "metadata": {},
+        "name": "Ada Starr",
+        "object": "card",
+        "tokenization_method": null
+      },
+      "source_transfer": null,
+      "statement_descriptor": "Zulip Cloud Premium",
+      "status": "succeeded",
+      "transfer_group": null
+    }
+  ],
+  "has_more": false,
+  "object": "list",
+  "url": "/v1/charges"
+}
diff --git a/corporate/tests/stripe_fixtures/attach_discount_to_realm:Customer.create.1.json b/corporate/tests/stripe_fixtures/attach_discount_to_realm:Customer.create.1.json
new file mode 100644
index 0000000000..18131f2ce6
--- /dev/null
+++ b/corporate/tests/stripe_fixtures/attach_discount_to_realm:Customer.create.1.json
@@ -0,0 +1,58 @@
+{
+  "account_balance": 0,
+  "created": 1543270381,
+  "currency": null,
+  "default_source": null,
+  "delinquent": false,
+  "description": "zulip (Zulip Dev)",
+  "discount": {
+    "coupon": {
+      "amount_off": null,
+      "created": 1539831972,
+      "currency": null,
+      "duration": "forever",
+      "duration_in_months": null,
+      "id": "wqkGqs8t",
+      "livemode": false,
+      "max_redemptions": null,
+      "metadata": {},
+      "name": "85% discount",
+      "object": "coupon",
+      "percent_off": 85.0,
+      "redeem_by": null,
+      "times_redeemed": 37,
+      "valid": true
+    },
+    "customer": "cus_NORMALIZED0001",
+    "end": null,
+    "object": "discount",
+    "start": 1543270381,
+    "subscription": null
+  },
+  "email": "hamlet@zulip.com",
+  "id": "cus_NORMALIZED0001",
+  "invoice_prefix": "NORMA01",
+  "livemode": false,
+  "metadata": {
+    "realm_id": "1",
+    "realm_str": "zulip"
+  },
+  "object": "customer",
+  "shipping": null,
+  "sources": {
+    "data": [],
+    "has_more": false,
+    "object": "list",
+    "total_count": 0,
+    "url": "/v1/customers/cus_NORMALIZED0001/sources"
+  },
+  "subscriptions": {
+    "data": [],
+    "has_more": false,
+    "object": "list",
+    "total_count": 0,
+    "url": "/v1/customers/cus_NORMALIZED0001/subscriptions"
+  },
+  "tax_info": null,
+  "tax_info_verification": null
+}
diff --git a/corporate/tests/stripe_fixtures/attach_discount_to_realm:Customer.retrieve.1.json b/corporate/tests/stripe_fixtures/attach_discount_to_realm:Customer.retrieve.1.json
new file mode 100644
index 0000000000..18131f2ce6
--- /dev/null
+++ b/corporate/tests/stripe_fixtures/attach_discount_to_realm:Customer.retrieve.1.json
@@ -0,0 +1,58 @@
+{
+  "account_balance": 0,
+  "created": 1543270381,
+  "currency": null,
+  "default_source": null,
+  "delinquent": false,
+  "description": "zulip (Zulip Dev)",
+  "discount": {
+    "coupon": {
+      "amount_off": null,
+      "created": 1539831972,
+      "currency": null,
+      "duration": "forever",
+      "duration_in_months": null,
+      "id": "wqkGqs8t",
+      "livemode": false,
+      "max_redemptions": null,
+      "metadata": {},
+      "name": "85% discount",
+      "object": "coupon",
+      "percent_off": 85.0,
+      "redeem_by": null,
+      "times_redeemed": 37,
+      "valid": true
+    },
+    "customer": "cus_NORMALIZED0001",
+    "end": null,
+    "object": "discount",
+    "start": 1543270381,
+    "subscription": null
+  },
+  "email": "hamlet@zulip.com",
+  "id": "cus_NORMALIZED0001",
+  "invoice_prefix": "NORMA01",
+  "livemode": false,
+  "metadata": {
+    "realm_id": "1",
+    "realm_str": "zulip"
+  },
+  "object": "customer",
+  "shipping": null,
+  "sources": {
+    "data": [],
+    "has_more": false,
+    "object": "list",
+    "total_count": 0,
+    "url": "/v1/customers/cus_NORMALIZED0001/sources"
+  },
+  "subscriptions": {
+    "data": [],
+    "has_more": false,
+    "object": "list",
+    "total_count": 0,
+    "url": "/v1/customers/cus_NORMALIZED0001/subscriptions"
+  },
+  "tax_info": null,
+  "tax_info_verification": null
+}
diff --git a/corporate/tests/stripe_fixtures/attach_discount_to_realm:Customer.retrieve.2.json b/corporate/tests/stripe_fixtures/attach_discount_to_realm:Customer.retrieve.2.json
new file mode 100644
index 0000000000..4bdce0f268
--- /dev/null
+++ b/corporate/tests/stripe_fixtures/attach_discount_to_realm:Customer.retrieve.2.json
@@ -0,0 +1,192 @@
+{
+  "account_balance": 0,
+  "created": 1543270381,
+  "currency": "usd",
+  "default_source": {
+    "address_city": "Pacific",
+    "address_country": "United States",
+    "address_line1": "Under the sea,",
+    "address_line1_check": "pass",
+    "address_line2": null,
+    "address_state": null,
+    "address_zip": "33333",
+    "address_zip_check": "pass",
+    "brand": "Visa",
+    "country": "US",
+    "customer": "cus_NORMALIZED0001",
+    "cvc_check": "pass",
+    "dynamic_last4": null,
+    "exp_month": 3,
+    "exp_year": 2033,
+    "fingerprint": "NORMALIZED000001",
+    "funding": "credit",
+    "id": "card_NORMALIZED00000000000001",
+    "last4": "4242",
+    "metadata": {},
+    "name": "Ada Starr",
+    "object": "card",
+    "tokenization_method": null
+  },
+  "delinquent": false,
+  "description": "zulip (Zulip Dev)",
+  "discount": {
+    "coupon": {
+      "amount_off": null,
+      "created": 1539831972,
+      "currency": null,
+      "duration": "forever",
+      "duration_in_months": null,
+      "id": "wqkGqs8t",
+      "livemode": false,
+      "max_redemptions": null,
+      "metadata": {},
+      "name": "85% discount",
+      "object": "coupon",
+      "percent_off": 85.0,
+      "redeem_by": null,
+      "times_redeemed": 37,
+      "valid": true
+    },
+    "customer": "cus_NORMALIZED0001",
+    "end": null,
+    "object": "discount",
+    "start": 1543270381,
+    "subscription": null
+  },
+  "email": "hamlet@zulip.com",
+  "id": "cus_NORMALIZED0001",
+  "invoice_prefix": "NORMA01",
+  "livemode": false,
+  "metadata": {
+    "realm_id": "1",
+    "realm_str": "zulip"
+  },
+  "object": "customer",
+  "shipping": null,
+  "sources": {
+    "data": [
+      {
+        "address_city": "Pacific",
+        "address_country": "United States",
+        "address_line1": "Under the sea,",
+        "address_line1_check": "pass",
+        "address_line2": null,
+        "address_state": null,
+        "address_zip": "33333",
+        "address_zip_check": "pass",
+        "brand": "Visa",
+        "country": "US",
+        "customer": "cus_NORMALIZED0001",
+        "cvc_check": "pass",
+        "dynamic_last4": null,
+        "exp_month": 3,
+        "exp_year": 2033,
+        "fingerprint": "NORMALIZED000001",
+        "funding": "credit",
+        "id": "card_NORMALIZED00000000000001",
+        "last4": "4242",
+        "metadata": {},
+        "name": "Ada Starr",
+        "object": "card",
+        "tokenization_method": null
+      }
+    ],
+    "has_more": false,
+    "object": "list",
+    "total_count": 1,
+    "url": "/v1/customers/cus_NORMALIZED0001/sources"
+  },
+  "subscriptions": {
+    "data": [
+      {
+        "application_fee_percent": null,
+        "billing": "charge_automatically",
+        "billing_cycle_anchor": 1543270384,
+        "cancel_at_period_end": false,
+        "canceled_at": null,
+        "created": 1543270384,
+        "current_period_end": 1574806384,
+        "current_period_start": 1543270384,
+        "customer": "cus_NORMALIZED0001",
+        "days_until_due": null,
+        "default_source": null,
+        "discount": null,
+        "ended_at": null,
+        "id": "sub_NORMALIZED0001",
+        "items": {
+          "data": [
+            {
+              "created": 1543270384,
+              "id": "si_NORMALIZED0001",
+              "metadata": {},
+              "object": "subscription_item",
+              "plan": {
+                "active": true,
+                "aggregate_usage": null,
+                "amount": 8000,
+                "billing_scheme": "per_unit",
+                "created": 1539831971,
+                "currency": "usd",
+                "id": "plan_Do3xCvbzO89OsR",
+                "interval": "year",
+                "interval_count": 1,
+                "livemode": false,
+                "metadata": {},
+                "nickname": "annual",
+                "object": "plan",
+                "product": "prod_Do3x494SetTDpx",
+                "tiers": null,
+                "tiers_mode": null,
+                "transform_usage": null,
+                "trial_period_days": null,
+                "usage_type": "licensed"
+              },
+              "quantity": 8,
+              "subscription": "sub_NORMALIZED0001"
+            }
+          ],
+          "has_more": false,
+          "object": "list",
+          "total_count": 1,
+          "url": "/v1/subscription_items?subscription=sub_NORMALIZED0001"
+        },
+        "livemode": false,
+        "metadata": {},
+        "object": "subscription",
+        "plan": {
+          "active": true,
+          "aggregate_usage": null,
+          "amount": 8000,
+          "billing_scheme": "per_unit",
+          "created": 1539831971,
+          "currency": "usd",
+          "id": "plan_Do3xCvbzO89OsR",
+          "interval": "year",
+          "interval_count": 1,
+          "livemode": false,
+          "metadata": {},
+          "nickname": "annual",
+          "object": "plan",
+          "product": "prod_Do3x494SetTDpx",
+          "tiers": null,
+          "tiers_mode": null,
+          "transform_usage": null,
+          "trial_period_days": null,
+          "usage_type": "licensed"
+        },
+        "quantity": 8,
+        "start": 1543270384,
+        "status": "active",
+        "tax_percent": 0.0,
+        "trial_end": null,
+        "trial_start": null
+      }
+    ],
+    "has_more": false,
+    "object": "list",
+    "total_count": 1,
+    "url": "/v1/customers/cus_NORMALIZED0001/subscriptions"
+  },
+  "tax_info": null,
+  "tax_info_verification": null
+}
diff --git a/corporate/tests/stripe_fixtures/attach_discount_to_realm:Customer.retrieve.3.json b/corporate/tests/stripe_fixtures/attach_discount_to_realm:Customer.retrieve.3.json
new file mode 100644
index 0000000000..4bdce0f268
--- /dev/null
+++ b/corporate/tests/stripe_fixtures/attach_discount_to_realm:Customer.retrieve.3.json
@@ -0,0 +1,192 @@
+{
+  "account_balance": 0,
+  "created": 1543270381,
+  "currency": "usd",
+  "default_source": {
+    "address_city": "Pacific",
+    "address_country": "United States",
+    "address_line1": "Under the sea,",
+    "address_line1_check": "pass",
+    "address_line2": null,
+    "address_state": null,
+    "address_zip": "33333",
+    "address_zip_check": "pass",
+    "brand": "Visa",
+    "country": "US",
+    "customer": "cus_NORMALIZED0001",
+    "cvc_check": "pass",
+    "dynamic_last4": null,
+    "exp_month": 3,
+    "exp_year": 2033,
+    "fingerprint": "NORMALIZED000001",
+    "funding": "credit",
+    "id": "card_NORMALIZED00000000000001",
+    "last4": "4242",
+    "metadata": {},
+    "name": "Ada Starr",
+    "object": "card",
+    "tokenization_method": null
+  },
+  "delinquent": false,
+  "description": "zulip (Zulip Dev)",
+  "discount": {
+    "coupon": {
+      "amount_off": null,
+      "created": 1539831972,
+      "currency": null,
+      "duration": "forever",
+      "duration_in_months": null,
+      "id": "wqkGqs8t",
+      "livemode": false,
+      "max_redemptions": null,
+      "metadata": {},
+      "name": "85% discount",
+      "object": "coupon",
+      "percent_off": 85.0,
+      "redeem_by": null,
+      "times_redeemed": 37,
+      "valid": true
+    },
+    "customer": "cus_NORMALIZED0001",
+    "end": null,
+    "object": "discount",
+    "start": 1543270381,
+    "subscription": null
+  },
+  "email": "hamlet@zulip.com",
+  "id": "cus_NORMALIZED0001",
+  "invoice_prefix": "NORMA01",
+  "livemode": false,
+  "metadata": {
+    "realm_id": "1",
+    "realm_str": "zulip"
+  },
+  "object": "customer",
+  "shipping": null,
+  "sources": {
+    "data": [
+      {
+        "address_city": "Pacific",
+        "address_country": "United States",
+        "address_line1": "Under the sea,",
+        "address_line1_check": "pass",
+        "address_line2": null,
+        "address_state": null,
+        "address_zip": "33333",
+        "address_zip_check": "pass",
+        "brand": "Visa",
+        "country": "US",
+        "customer": "cus_NORMALIZED0001",
+        "cvc_check": "pass",
+        "dynamic_last4": null,
+        "exp_month": 3,
+        "exp_year": 2033,
+        "fingerprint": "NORMALIZED000001",
+        "funding": "credit",
+        "id": "card_NORMALIZED00000000000001",
+        "last4": "4242",
+        "metadata": {},
+        "name": "Ada Starr",
+        "object": "card",
+        "tokenization_method": null
+      }
+    ],
+    "has_more": false,
+    "object": "list",
+    "total_count": 1,
+    "url": "/v1/customers/cus_NORMALIZED0001/sources"
+  },
+  "subscriptions": {
+    "data": [
+      {
+        "application_fee_percent": null,
+        "billing": "charge_automatically",
+        "billing_cycle_anchor": 1543270384,
+        "cancel_at_period_end": false,
+        "canceled_at": null,
+        "created": 1543270384,
+        "current_period_end": 1574806384,
+        "current_period_start": 1543270384,
+        "customer": "cus_NORMALIZED0001",
+        "days_until_due": null,
+        "default_source": null,
+        "discount": null,
+        "ended_at": null,
+        "id": "sub_NORMALIZED0001",
+        "items": {
+          "data": [
+            {
+              "created": 1543270384,
+              "id": "si_NORMALIZED0001",
+              "metadata": {},
+              "object": "subscription_item",
+              "plan": {
+                "active": true,
+                "aggregate_usage": null,
+                "amount": 8000,
+                "billing_scheme": "per_unit",
+                "created": 1539831971,
+                "currency": "usd",
+                "id": "plan_Do3xCvbzO89OsR",
+                "interval": "year",
+                "interval_count": 1,
+                "livemode": false,
+                "metadata": {},
+                "nickname": "annual",
+                "object": "plan",
+                "product": "prod_Do3x494SetTDpx",
+                "tiers": null,
+                "tiers_mode": null,
+                "transform_usage": null,
+                "trial_period_days": null,
+                "usage_type": "licensed"
+              },
+              "quantity": 8,
+              "subscription": "sub_NORMALIZED0001"
+            }
+          ],
+          "has_more": false,
+          "object": "list",
+          "total_count": 1,
+          "url": "/v1/subscription_items?subscription=sub_NORMALIZED0001"
+        },
+        "livemode": false,
+        "metadata": {},
+        "object": "subscription",
+        "plan": {
+          "active": true,
+          "aggregate_usage": null,
+          "amount": 8000,
+          "billing_scheme": "per_unit",
+          "created": 1539831971,
+          "currency": "usd",
+          "id": "plan_Do3xCvbzO89OsR",
+          "interval": "year",
+          "interval_count": 1,
+          "livemode": false,
+          "metadata": {},
+          "nickname": "annual",
+          "object": "plan",
+          "product": "prod_Do3x494SetTDpx",
+          "tiers": null,
+          "tiers_mode": null,
+          "transform_usage": null,
+          "trial_period_days": null,
+          "usage_type": "licensed"
+        },
+        "quantity": 8,
+        "start": 1543270384,
+        "status": "active",
+        "tax_percent": 0.0,
+        "trial_end": null,
+        "trial_start": null
+      }
+    ],
+    "has_more": false,
+    "object": "list",
+    "total_count": 1,
+    "url": "/v1/customers/cus_NORMALIZED0001/subscriptions"
+  },
+  "tax_info": null,
+  "tax_info_verification": null
+}
diff --git a/corporate/tests/stripe_fixtures/attach_discount_to_realm:Customer.save.1.json b/corporate/tests/stripe_fixtures/attach_discount_to_realm:Customer.save.1.json
new file mode 100644
index 0000000000..61dbdfc37d
--- /dev/null
+++ b/corporate/tests/stripe_fixtures/attach_discount_to_realm:Customer.save.1.json
@@ -0,0 +1,84 @@
+{
+  "account_balance": 0,
+  "created": 1543270381,
+  "currency": null,
+  "default_source": "card_NORMALIZED00000000000001",
+  "delinquent": false,
+  "description": "zulip (Zulip Dev)",
+  "discount": {
+    "coupon": {
+      "amount_off": null,
+      "created": 1539831972,
+      "currency": null,
+      "duration": "forever",
+      "duration_in_months": null,
+      "id": "wqkGqs8t",
+      "livemode": false,
+      "max_redemptions": null,
+      "metadata": {},
+      "name": "85% discount",
+      "object": "coupon",
+      "percent_off": 85.0,
+      "redeem_by": null,
+      "times_redeemed": 37,
+      "valid": true
+    },
+    "customer": "cus_NORMALIZED0001",
+    "end": null,
+    "object": "discount",
+    "start": 1543270381,
+    "subscription": null
+  },
+  "email": "hamlet@zulip.com",
+  "id": "cus_NORMALIZED0001",
+  "invoice_prefix": "NORMA01",
+  "livemode": false,
+  "metadata": {
+    "realm_id": "1",
+    "realm_str": "zulip"
+  },
+  "object": "customer",
+  "shipping": null,
+  "sources": {
+    "data": [
+      {
+        "address_city": "Pacific",
+        "address_country": "United States",
+        "address_line1": "Under the sea,",
+        "address_line1_check": "pass",
+        "address_line2": null,
+        "address_state": null,
+        "address_zip": "33333",
+        "address_zip_check": "pass",
+        "brand": "Visa",
+        "country": "US",
+        "customer": "cus_NORMALIZED0001",
+        "cvc_check": "pass",
+        "dynamic_last4": null,
+        "exp_month": 3,
+        "exp_year": 2033,
+        "fingerprint": "NORMALIZED000001",
+        "funding": "credit",
+        "id": "card_NORMALIZED00000000000001",
+        "last4": "4242",
+        "metadata": {},
+        "name": "Ada Starr",
+        "object": "card",
+        "tokenization_method": null
+      }
+    ],
+    "has_more": false,
+    "object": "list",
+    "total_count": 1,
+    "url": "/v1/customers/cus_NORMALIZED0001/sources"
+  },
+  "subscriptions": {
+    "data": [],
+    "has_more": false,
+    "object": "list",
+    "total_count": 0,
+    "url": "/v1/customers/cus_NORMALIZED0001/subscriptions"
+  },
+  "tax_info": null,
+  "tax_info_verification": null
+}
diff --git a/corporate/tests/stripe_fixtures/attach_discount_to_realm:Customer.save.2.json b/corporate/tests/stripe_fixtures/attach_discount_to_realm:Customer.save.2.json
new file mode 100644
index 0000000000..2e15484f70
--- /dev/null
+++ b/corporate/tests/stripe_fixtures/attach_discount_to_realm:Customer.save.2.json
@@ -0,0 +1,168 @@
+{
+  "account_balance": 0,
+  "created": 1543270381,
+  "currency": "usd",
+  "default_source": "card_NORMALIZED00000000000001",
+  "delinquent": false,
+  "description": "zulip (Zulip Dev)",
+  "discount": {
+    "coupon": {
+      "amount_off": null,
+      "created": 1539831971,
+      "currency": null,
+      "duration": "forever",
+      "duration_in_months": null,
+      "id": "00otHgC9",
+      "livemode": false,
+      "max_redemptions": null,
+      "metadata": {},
+      "name": "25% discount",
+      "object": "coupon",
+      "percent_off": 25.0,
+      "redeem_by": null,
+      "times_redeemed": 19,
+      "valid": true
+    },
+    "customer": "cus_NORMALIZED0001",
+    "end": null,
+    "object": "discount",
+    "start": 1543270387,
+    "subscription": null
+  },
+  "email": "hamlet@zulip.com",
+  "id": "cus_NORMALIZED0001",
+  "invoice_prefix": "NORMA01",
+  "livemode": false,
+  "metadata": {
+    "realm_id": "1",
+    "realm_str": "zulip"
+  },
+  "object": "customer",
+  "shipping": null,
+  "sources": {
+    "data": [
+      {
+        "address_city": "Pacific",
+        "address_country": "United States",
+        "address_line1": "Under the sea,",
+        "address_line1_check": "pass",
+        "address_line2": null,
+        "address_state": null,
+        "address_zip": "33333",
+        "address_zip_check": "pass",
+        "brand": "Visa",
+        "country": "US",
+        "customer": "cus_NORMALIZED0001",
+        "cvc_check": "pass",
+        "dynamic_last4": null,
+        "exp_month": 3,
+        "exp_year": 2033,
+        "fingerprint": "NORMALIZED000001",
+        "funding": "credit",
+        "id": "card_NORMALIZED00000000000001",
+        "last4": "4242",
+        "metadata": {},
+        "name": "Ada Starr",
+        "object": "card",
+        "tokenization_method": null
+      }
+    ],
+    "has_more": false,
+    "object": "list",
+    "total_count": 1,
+    "url": "/v1/customers/cus_NORMALIZED0001/sources"
+  },
+  "subscriptions": {
+    "data": [
+      {
+        "application_fee_percent": null,
+        "billing": "charge_automatically",
+        "billing_cycle_anchor": 1543270384,
+        "cancel_at_period_end": false,
+        "canceled_at": null,
+        "created": 1543270384,
+        "current_period_end": 1574806384,
+        "current_period_start": 1543270384,
+        "customer": "cus_NORMALIZED0001",
+        "days_until_due": null,
+        "default_source": null,
+        "discount": null,
+        "ended_at": null,
+        "id": "sub_NORMALIZED0001",
+        "items": {
+          "data": [
+            {
+              "created": 1543270384,
+              "id": "si_NORMALIZED0001",
+              "metadata": {},
+              "object": "subscription_item",
+              "plan": {
+                "active": true,
+                "aggregate_usage": null,
+                "amount": 8000,
+                "billing_scheme": "per_unit",
+                "created": 1539831971,
+                "currency": "usd",
+                "id": "plan_Do3xCvbzO89OsR",
+                "interval": "year",
+                "interval_count": 1,
+                "livemode": false,
+                "metadata": {},
+                "nickname": "annual",
+                "object": "plan",
+                "product": "prod_Do3x494SetTDpx",
+                "tiers": null,
+                "tiers_mode": null,
+                "transform_usage": null,
+                "trial_period_days": null,
+                "usage_type": "licensed"
+              },
+              "quantity": 8,
+              "subscription": "sub_NORMALIZED0001"
+            }
+          ],
+          "has_more": false,
+          "object": "list",
+          "total_count": 1,
+          "url": "/v1/subscription_items?subscription=sub_NORMALIZED0001"
+        },
+        "livemode": false,
+        "metadata": {},
+        "object": "subscription",
+        "plan": {
+          "active": true,
+          "aggregate_usage": null,
+          "amount": 8000,
+          "billing_scheme": "per_unit",
+          "created": 1539831971,
+          "currency": "usd",
+          "id": "plan_Do3xCvbzO89OsR",
+          "interval": "year",
+          "interval_count": 1,
+          "livemode": false,
+          "metadata": {},
+          "nickname": "annual",
+          "object": "plan",
+          "product": "prod_Do3x494SetTDpx",
+          "tiers": null,
+          "tiers_mode": null,
+          "transform_usage": null,
+          "trial_period_days": null,
+          "usage_type": "licensed"
+        },
+        "quantity": 8,
+        "start": 1543270384,
+        "status": "active",
+        "tax_percent": 0.0,
+        "trial_end": null,
+        "trial_start": null
+      }
+    ],
+    "has_more": false,
+    "object": "list",
+    "total_count": 1,
+    "url": "/v1/customers/cus_NORMALIZED0001/subscriptions"
+  },
+  "tax_info": null,
+  "tax_info_verification": null
+}
diff --git a/corporate/tests/stripe_fixtures/attach_discount_to_realm:Invoice.upcoming.1.json b/corporate/tests/stripe_fixtures/attach_discount_to_realm:Invoice.upcoming.1.json
new file mode 100644
index 0000000000..660f9f3b2c
--- /dev/null
+++ b/corporate/tests/stripe_fixtures/attach_discount_to_realm:Invoice.upcoming.1.json
@@ -0,0 +1,110 @@
+{
+  "amount_due": 9600,
+  "amount_paid": 0,
+  "amount_remaining": 9600,
+  "application_fee": null,
+  "attempt_count": 0,
+  "attempted": false,
+  "billing": "charge_automatically",
+  "billing_reason": "upcoming",
+  "charge": null,
+  "currency": "usd",
+  "customer": "cus_NORMALIZED0001",
+  "date": 1574806384,
+  "default_source": null,
+  "description": "",
+  "discount": {
+    "coupon": {
+      "amount_off": null,
+      "created": 1539831972,
+      "currency": null,
+      "duration": "forever",
+      "duration_in_months": null,
+      "id": "wqkGqs8t",
+      "livemode": false,
+      "max_redemptions": null,
+      "metadata": {},
+      "name": "85% discount",
+      "object": "coupon",
+      "percent_off": 85.0,
+      "redeem_by": null,
+      "times_redeemed": 37,
+      "valid": true
+    },
+    "customer": "cus_NORMALIZED0001",
+    "end": null,
+    "object": "discount",
+    "start": 1543270381,
+    "subscription": null
+  },
+  "due_date": null,
+  "ending_balance": 0,
+  "finalized_at": null,
+  "lines": {
+    "data": [
+      {
+        "amount": 64000,
+        "currency": "usd",
+        "description": "8 user \u00d7 Zulip Cloud Premium (at $80.00 / year)",
+        "discountable": true,
+        "id": "sli_NORMALIZED0001",
+        "livemode": false,
+        "metadata": {},
+        "object": "line_item",
+        "period": {
+          "end": 1606428784,
+          "start": 1574806384
+        },
+        "plan": {
+          "active": true,
+          "aggregate_usage": null,
+          "amount": 8000,
+          "billing_scheme": "per_unit",
+          "created": 1539831971,
+          "currency": "usd",
+          "id": "plan_Do3xCvbzO89OsR",
+          "interval": "year",
+          "interval_count": 1,
+          "livemode": false,
+          "metadata": {},
+          "nickname": "annual",
+          "object": "plan",
+          "product": "prod_Do3x494SetTDpx",
+          "tiers": null,
+          "tiers_mode": null,
+          "transform_usage": null,
+          "trial_period_days": null,
+          "usage_type": "licensed"
+        },
+        "proration": false,
+        "quantity": 8,
+        "subscription": "sub_NORMALIZED0001",
+        "subscription_item": "si_NORMALIZED0001",
+        "type": "subscription"
+      }
+    ],
+    "has_more": false,
+    "object": "list",
+    "total_count": 1,
+    "url": "/v1/invoices/upcoming/lines?customer=cus_NORMALIZED0001"
+  },
+  "livemode": false,
+  "metadata": {},
+  "next_payment_attempt": 1574809984,
+  "number": "NORMALI-0001",
+  "object": "invoice",
+  "paid": false,
+  "payment_intent": null,
+  "period_end": 1574806384,
+  "period_start": 1543270384,
+  "receipt_number": null,
+  "starting_balance": 0,
+  "statement_descriptor": null,
+  "status": "draft",
+  "subscription": "sub_NORMALIZED0001",
+  "subtotal": 64000,
+  "tax": 0,
+  "tax_percent": 0.0,
+  "total": 9600,
+  "webhooks_delivered_at": null
+}
diff --git a/corporate/tests/stripe_fixtures/attach_discount_to_realm:Invoice.upcoming.2.json b/corporate/tests/stripe_fixtures/attach_discount_to_realm:Invoice.upcoming.2.json
new file mode 100644
index 0000000000..0dede69d4f
--- /dev/null
+++ b/corporate/tests/stripe_fixtures/attach_discount_to_realm:Invoice.upcoming.2.json
@@ -0,0 +1,110 @@
+{
+  "amount_due": 48000,
+  "amount_paid": 0,
+  "amount_remaining": 48000,
+  "application_fee": null,
+  "attempt_count": 0,
+  "attempted": false,
+  "billing": "charge_automatically",
+  "billing_reason": "upcoming",
+  "charge": null,
+  "currency": "usd",
+  "customer": "cus_NORMALIZED0001",
+  "date": 1574806384,
+  "default_source": null,
+  "description": "",
+  "discount": {
+    "coupon": {
+      "amount_off": null,
+      "created": 1539831971,
+      "currency": null,
+      "duration": "forever",
+      "duration_in_months": null,
+      "id": "00otHgC9",
+      "livemode": false,
+      "max_redemptions": null,
+      "metadata": {},
+      "name": "25% discount",
+      "object": "coupon",
+      "percent_off": 25.0,
+      "redeem_by": null,
+      "times_redeemed": 19,
+      "valid": true
+    },
+    "customer": "cus_NORMALIZED0001",
+    "end": null,
+    "object": "discount",
+    "start": 1543270387,
+    "subscription": null
+  },
+  "due_date": null,
+  "ending_balance": 0,
+  "finalized_at": null,
+  "lines": {
+    "data": [
+      {
+        "amount": 64000,
+        "currency": "usd",
+        "description": "8 user \u00d7 Zulip Cloud Premium (at $80.00 / year)",
+        "discountable": true,
+        "id": "sli_NORMALIZED0001",
+        "livemode": false,
+        "metadata": {},
+        "object": "line_item",
+        "period": {
+          "end": 1606428784,
+          "start": 1574806384
+        },
+        "plan": {
+          "active": true,
+          "aggregate_usage": null,
+          "amount": 8000,
+          "billing_scheme": "per_unit",
+          "created": 1539831971,
+          "currency": "usd",
+          "id": "plan_Do3xCvbzO89OsR",
+          "interval": "year",
+          "interval_count": 1,
+          "livemode": false,
+          "metadata": {},
+          "nickname": "annual",
+          "object": "plan",
+          "product": "prod_Do3x494SetTDpx",
+          "tiers": null,
+          "tiers_mode": null,
+          "transform_usage": null,
+          "trial_period_days": null,
+          "usage_type": "licensed"
+        },
+        "proration": false,
+        "quantity": 8,
+        "subscription": "sub_NORMALIZED0001",
+        "subscription_item": "si_NORMALIZED0001",
+        "type": "subscription"
+      }
+    ],
+    "has_more": false,
+    "object": "list",
+    "total_count": 1,
+    "url": "/v1/invoices/upcoming/lines?customer=cus_NORMALIZED0001"
+  },
+  "livemode": false,
+  "metadata": {},
+  "next_payment_attempt": 1574809984,
+  "number": "NORMALI-0001",
+  "object": "invoice",
+  "paid": false,
+  "payment_intent": null,
+  "period_end": 1574806384,
+  "period_start": 1543270384,
+  "receipt_number": null,
+  "starting_balance": 0,
+  "statement_descriptor": null,
+  "status": "draft",
+  "subscription": "sub_NORMALIZED0001",
+  "subtotal": 64000,
+  "tax": 0,
+  "tax_percent": 0.0,
+  "total": 48000,
+  "webhooks_delivered_at": null
+}
diff --git a/corporate/tests/stripe_fixtures/attach_discount_to_realm:Subscription.create.1.json b/corporate/tests/stripe_fixtures/attach_discount_to_realm:Subscription.create.1.json
new file mode 100644
index 0000000000..060ed392ce
--- /dev/null
+++ b/corporate/tests/stripe_fixtures/attach_discount_to_realm:Subscription.create.1.json
@@ -0,0 +1,83 @@
+{
+  "application_fee_percent": null,
+  "billing": "charge_automatically",
+  "billing_cycle_anchor": 1543270384,
+  "cancel_at_period_end": false,
+  "canceled_at": null,
+  "created": 1543270384,
+  "current_period_end": 1574806384,
+  "current_period_start": 1543270384,
+  "customer": "cus_NORMALIZED0001",
+  "days_until_due": null,
+  "default_source": null,
+  "discount": null,
+  "ended_at": null,
+  "id": "sub_NORMALIZED0001",
+  "items": {
+    "data": [
+      {
+        "created": 1543270384,
+        "id": "si_NORMALIZED0001",
+        "metadata": {},
+        "object": "subscription_item",
+        "plan": {
+          "active": true,
+          "aggregate_usage": null,
+          "amount": 8000,
+          "billing_scheme": "per_unit",
+          "created": 1539831971,
+          "currency": "usd",
+          "id": "plan_Do3xCvbzO89OsR",
+          "interval": "year",
+          "interval_count": 1,
+          "livemode": false,
+          "metadata": {},
+          "nickname": "annual",
+          "object": "plan",
+          "product": "prod_Do3x494SetTDpx",
+          "tiers": null,
+          "tiers_mode": null,
+          "transform_usage": null,
+          "trial_period_days": null,
+          "usage_type": "licensed"
+        },
+        "quantity": 8,
+        "subscription": "sub_NORMALIZED0001"
+      }
+    ],
+    "has_more": false,
+    "object": "list",
+    "total_count": 1,
+    "url": "/v1/subscription_items?subscription=sub_NORMALIZED0001"
+  },
+  "livemode": false,
+  "metadata": {},
+  "object": "subscription",
+  "plan": {
+    "active": true,
+    "aggregate_usage": null,
+    "amount": 8000,
+    "billing_scheme": "per_unit",
+    "created": 1539831971,
+    "currency": "usd",
+    "id": "plan_Do3xCvbzO89OsR",
+    "interval": "year",
+    "interval_count": 1,
+    "livemode": false,
+    "metadata": {},
+    "nickname": "annual",
+    "object": "plan",
+    "product": "prod_Do3x494SetTDpx",
+    "tiers": null,
+    "tiers_mode": null,
+    "transform_usage": null,
+    "trial_period_days": null,
+    "usage_type": "licensed"
+  },
+  "quantity": 8,
+  "start": 1543270384,
+  "status": "active",
+  "tax_percent": 0.0,
+  "trial_end": null,
+  "trial_start": null
+}
diff --git a/corporate/tests/stripe_fixtures/attach_discount_to_realm:Token.create.1.json b/corporate/tests/stripe_fixtures/attach_discount_to_realm:Token.create.1.json
new file mode 100644
index 0000000000..886506584a
--- /dev/null
+++ b/corporate/tests/stripe_fixtures/attach_discount_to_realm:Token.create.1.json
@@ -0,0 +1,33 @@
+{
+  "card": {
+    "address_city": "Pacific",
+    "address_country": "United States",
+    "address_line1": "Under the sea,",
+    "address_line1_check": "unchecked",
+    "address_line2": null,
+    "address_state": null,
+    "address_zip": "33333",
+    "address_zip_check": "unchecked",
+    "brand": "Visa",
+    "country": "US",
+    "cvc_check": "unchecked",
+    "dynamic_last4": null,
+    "exp_month": 3,
+    "exp_year": 2033,
+    "fingerprint": "NORMALIZED000001",
+    "funding": "credit",
+    "id": "card_NORMALIZED00000000000001",
+    "last4": "4242",
+    "metadata": {},
+    "name": "Ada Starr",
+    "object": "card",
+    "tokenization_method": null
+  },
+  "client_ip": "0.0.0.0",
+  "created": 1543270382,
+  "id": "tok_NORMALIZED00000000000001",
+  "livemode": false,
+  "object": "token",
+  "type": "card",
+  "used": false
+}
diff --git a/corporate/tests/test_stripe.py b/corporate/tests/test_stripe.py
index b94576abb6..1755d8bc8b 100644
--- a/corporate/tests/test_stripe.py
+++ b/corporate/tests/test_stripe.py
@@ -740,24 +740,36 @@ class StripeTest(ZulipTestCase):
         stripe_customer = stripe_get_customer(Customer.objects.get(realm=user.realm).stripe_customer_id)
         self.assertIn('Unknown payment method.', payment_method_string(stripe_customer))
 
-    @patch("stripe.Customer.retrieve", side_effect=mock_create_customer)
-    @patch("stripe.Customer.create", side_effect=mock_create_customer)
-    def test_attach_discount_to_realm(self, mock_create_customer: Mock,
-                                      mock_retrieve_customer: Mock) -> None:
+    @mock_stripe("Customer.save", "Customer.retrieve", "Customer.create", "Invoice.upcoming",
+                 "Token.create", "Charge.list", "Subscription.create")
+    def test_attach_discount_to_realm(self, mock7: Mock, mock6: Mock, mock5: Mock, mock4: Mock,
+                                      mock3: Mock, mock2: Mock, mock1: Mock) -> None:
+        # Attach discount before Stripe customer exists
         user = self.example_user('hamlet')
-        # Before customer exists
         attach_discount_to_realm(user, 85)
-        mock_create_customer.assert_called_once_with(
-            description=Kandra(), email=self.example_email('hamlet'), metadata=Kandra(),
-            source=None, coupon=self.stripe_coupon_id)
-        mock_create_customer.reset_mock()
-        # For existing customer
-        Coupon.objects.create(percent_off=42, stripe_coupon_id='42OFF')
-        with patch.object(
-                stripe.Customer, 'save', autospec=True,
-                side_effect=lambda stripe_customer: self.assertEqual(stripe_customer.coupon, '42OFF')):
-            attach_discount_to_realm(user, 42)
-        mock_create_customer.assert_not_called()
+        self.login(user.email)
+        response = self.client_get("/upgrade/")
+        self.client_post("/upgrade/", {'stripeToken': stripe_create_token().id,
+                                       'signed_seat_count': self.get_signed_seat_count_from_response(response),
+                                       'salt': self.get_salt_from_response(response),
+                                       'plan': Plan.CLOUD_ANNUAL,
+                                       'billing_modality': 'charge_automatically'})
+        stripe_customer = stripe_get_customer(Customer.objects.get(realm=user.realm).stripe_customer_id)
+        assert(stripe_customer.discount is not None)  # for mypy
+        self.assertEqual(stripe_customer.discount.coupon.percent_off, 85.0)
+        # Check that the customer was charged the discounted amount
+        charges = stripe.Charge.list(customer=stripe_customer.id)
+        for charge in charges:
+            self.assertEqual(charge.amount, get_seat_count(user.realm) * 80 * 15)
+        # Check upcoming invoice reflects the discount
+        upcoming_invoice = stripe.Invoice.upcoming(customer=stripe_customer.id)
+        self.assertEqual(upcoming_invoice.amount_due, get_seat_count(user.realm) * 80 * 15)
+
+        # Attach discount to existing Stripe customer
+        attach_discount_to_realm(user, 25)
+        # Check upcoming invoice reflects the new discount
+        upcoming_invoice = stripe.Invoice.upcoming(customer=stripe_customer.id)
+        self.assertEqual(upcoming_invoice.amount_due, get_seat_count(user.realm) * 80 * 75)
 
     @patch("stripe.Subscription.delete")
     @patch("stripe.Customer.save")
diff --git a/stubs/stripe/__init__.pyi b/stubs/stripe/__init__.pyi
index 8be2b715d9..d603eef828 100644
--- a/stubs/stripe/__init__.pyi
+++ b/stubs/stripe/__init__.pyi
@@ -124,3 +124,10 @@ class Token:
     @staticmethod
     def create(card: Dict[str, Any]) -> Token:
         ...
+
+class Charge:
+    amount: int
+
+    @staticmethod
+    def list(customer: Optional[str]) -> List[Charge]:
+        ...