Updating a Subscription

Available via: Dashboard and API

Every change to an existing subscription goes through a single declarative endpoint:

PATCH /subscription/{subscriptionId}

You describe the desired change in the request body, and Inflow figures out the rest — whether it is an upgrade or a downgrade, whether something needs to be charged or credited, and when the change takes effect.

Exactly one operation group is accepted per call. Mixing groups (for example, a plan change and a pause in the same request) returns a 400:

Sending only name and/or description is a plain rename of the subscription: no billing change, nothing is charged.

Changing the Plan (Upgrades & Downgrades)

Set the new price and/or billing cycle:

Whether a change is an upgrade or a downgrade is resolved from the price per day, not the absolute amount. Moving from €10/month to €96/year raises the invoice amount but lowers the daily price — Inflow treats it as a downgrade.

Proration Behaviors

prorationBehavior folds two choices into one value: when the change applies (now or at the next billing date) and whether to prorate.

Defaults

If you omit prorationBehavior, Inflow picks the behavior a customer would expect:

Rules & Restrictions

• Plan changes require the subscription to be ACTIVE.
• No cash refunds — when a change generates a credit, it stays on the customer's balance and is consumed by upcoming invoices.
• Instant price decreases (PRORATE_NOW / FULL_CHARGE_NOW) are available for EUR and USD subscriptions.
• cycleCount can only be combined with a cycle change when that change applies immediately (not with NEXT_PERIOD), and never with a shorter cycle.
• Only one plan change can be in flight at a time; canceling the subscription also cancels any pending plan change.

Examples

Upgrade — prorated charge now (default):

curl -X PATCH https://api.inflowpay.xyz/subscription/{subscriptionId} \
  -H "X-Inflow-Api-Key: your_private_key" \
  -H "Content-Type: application/json" \
  -d '{ "amountInCents": 4999, "name": "Premium Plan" }'

The customer is charged (new price − old price) × (days remaining / days in cycle) immediately, and the new price applies from now on.

Downgrade — takes effect at the next billing date (default):

curl -X PATCH https://api.inflowpay.xyz/subscription/{subscriptionId} \
  -H "X-Inflow-Api-Key: your_private_key" \
  -H "Content-Type: application/json" \
  -d '{ "amountInCents": 1999 }'

Nothing changes until the current period ends; the next invoice uses the new price.

Downgrade — immediately, with credit for the unused portion:

curl -X PATCH https://api.inflowpay.xyz/subscription/{subscriptionId} \
  -H "X-Inflow-Api-Key: your_private_key" \
  -H "Content-Type: application/json" \
  -d '{ "amountInCents": 1999, "prorationBehavior": "PRORATE_NOW" }'

A fresh billing cycle starts today. The unused portion of the old cycle is credited to the customer's balance and deducted from the amount due; if the credit exceeds the new price, the remainder covers future invoices.

Switch from monthly to yearly billing:

curl -X PATCH https://api.inflowpay.xyz/subscription/{subscriptionId} \
  -H "X-Inflow-Api-Key: your_private_key" \
  -H "Content-Type: application/json" \
  -d '{ "amountInCents": 9900, "interval": "year", "intervalCount": 1 }'

The yearly cycle starts today, the unused days of the current month are credited, and the net is charged.

End an unlimited subscription after a set number of cycles:

curl -X PATCH https://api.inflowpay.xyz/subscription/{subscriptionId} \
  -H "X-Inflow-Api-Key: your_private_key" \
  -H "Content-Type: application/json" \
  -d '{ "cycleCount": 12 }'

The subscription automatically cancels after 12 billing cycles, the current cycle counting as the first.

Understanding the Response

The response tells you exactly what happened, so a preview call is not needed:

Pausing & Resuming Billing

Pause payment collection on an active subscription — invoices generated while paused are voided and the status becomes PAUSED:

curl -X PATCH https://api.inflowpay.xyz/subscription/{subscriptionId} \
  -H "X-Inflow-Api-Key: your_private_key" \
  -H "Content-Type: application/json" \
  -d '{ "pauseCollection": { "resumesAt": "2026-09-01T00:00:00.000Z" } }'

resumesAt is optional — without it, the subscription stays paused until you resume it explicitly by passing null:

curl -X PATCH https://api.inflowpay.xyz/subscription/{subscriptionId} \
  -H "X-Inflow-Api-Key: your_private_key" \
  -H "Content-Type: application/json" \
  -d '{ "pauseCollection": null }'

Extending Trials & Postponing Billing

trialEnd moves the next billing date — forward only, at most one year ahead. Nothing is charged during the gap.

curl -X PATCH https://api.inflowpay.xyz/subscription/{subscriptionId} \
  -H "X-Inflow-Api-Key: your_private_key" \
  -H "Content-Type: application/json" \
  -d '{ "trialEnd": "2026-09-01T00:00:00.000Z" }'

Canceling & Reactivating

Schedule a cancellation at the end of the current billing period (the subscription enters PENDING_CANCELLATION):

curl -X PATCH https://api.inflowpay.xyz/subscription/{subscriptionId} \
  -H "X-Inflow-Api-Key: your_private_key" \
  -H "Content-Type: application/json" \
  -d '{ "cancelAtPeriodEnd": true }'

Reactivate a subscription in PENDING_CANCELLATION before the period ends:

curl -X PATCH https://api.inflowpay.xyz/subscription/{subscriptionId} \
  -H "X-Inflow-Api-Key: your_private_key" \
  -H "Content-Type: application/json" \
  -d '{ "cancelAtPeriodEnd": false }'

To cancel immediately instead, use DELETE /subscription/{subscriptionId} with { "cancelNow": true } — see Managing Subscriptions.

From the Dashboard

The same operations are available from the subscription details page in your Dashboard:

1. Go to Subscriptions and open a subscription.
2. Choose the action: Change Plan (price, billing cycle, end date, with the same proration options), Pause / Resume, Extend Trial, or Cancel / Reactivate.
3. For plan changes, the Dashboard shows the amount charged or credited before you confirm.

Dashboard-initiated charges are always settled on the customer's saved payment method.

Migrating from Deprecated Endpoints

The following endpoints are deprecated and fully replaced by the unified PATCH:

See the API Reference for the full request and response schemas.