Upgrade or Downgrade a Subscription

Use POST /subscription/{id}/change-plan to move a subscriber to a different plan — either upgrading to a higher-priced tier or downgrading to a lower one. You control whether the change takes effect immediately (with proration charged or absorbed today) or is scheduled for the next billing cycle.

A plan’s amount, interval, and intervalCount are immutable once it has active subscribers. To change pricing or cadence, create a new plan and use this endpoint to migrate subscribers to it.

planId (target plan) is required; applyAt (now | next_billing, defaults to next_billing) controls timing — see the parameters panel above.

Response

Returns 200 OK with the updated subscription object. When applyAt is "next_billing", the response includes a scheduledPlanChange object with the planId and effectiveAt timestamp.

Errors

Code	Meaning
`400`	Target plan not found, inactive, or not available in the subscriber’s country.
`402`	Immediate proration charge declined (only when `applyAt: "now"`).
`404`	Subscription not found.
`422`	Validation error.

curl -X POST https://api.therius.io/v1/subscription/sub_abc123def456/change-plan \
  -H "Authorization: Bearer prv_production_your_key_here" \
  -H "Idempotency-Key: $(uuidgen)" \
  -H "Content-Type: application/json" \
  -d '{
    "merchantCode": "MERCHANT_001",
    "planId": 99,
    "applyAt": "now"
  }'

{}

If you want to offer a discounted intro period on the new plan, create the new plan with introAmount and introBillingCycles set before running change-plan. The subscriber will receive the intro pricing from their first cycle on the new plan.

Authorizations

Authorization

string

header

required

Your secret API key: Bearer prv_production_xxx (production) or Bearer prv_sandbox_xxx (sandbox).

Path Parameters

string

required

Body

application/json

merchantCode

string

required

Your merchant account identifier.

planId

integer

required

ID of the plan to switch to.

applyAt

enum<string>

When the change takes effect. next_billing (default) stores it as pending and applies it at the next cycle with no immediate charge. now applies immediately - an upgrade charges the prorated difference by MIT straight away; a downgrade switches immediately with no refund and the lower amount takes effect next cycle.

Available options:

now,

next_billing

Response

200 - application/json

Plan changed

A customer enrollment in a plan. plan is embedded on single-subscription responses. Invoice/event history is not included here - use the invoice endpoints.

string

Subscription UUID.

merchantId

integer

The merchant account that owns the subscription.

planId

integer

ID of the plan this subscription is enrolled in.

customerEmail

string

Subscriber email, used for billing and dunning notifications.

customerName

string

Subscriber name as it appears on invoices.

customerDocument

string

Subscriber national ID / tax document, where a market requires it (e.g. Brazil CPF/CNPJ).

cardBrand

string

Brand of the card on the mandate, e.g. visa.

status

enum<string>

pending - awaiting first charge; trialing - in a free trial; active - billing normally; past_due - a renewal failed and dunning is running; suspended - dunning exhausted, needs a new CIT (POST /subscription/{id}/payment-method in CIT mode) to recover; paused - billing stopped on request, resumable; cancelled - terminated; completed - reached maxBillingCycles.

Available options:

pending,

trialing,

active,

past_due,

suspended,

paused,

cancelled,

completed

currentPeriodStart

string<date-time>

Start of the current billing period.

currentPeriodEnd

string<date-time>

End of the current billing period.

nextBillingDate

string<date-time>

When the next renewal charge is scheduled.

trialStart

string<date-time>

Trial start, when the plan has a trial.

trialEnd

string<date-time>

Trial end - the first real charge date.

dunningAttemptCount

integer

Failed-renewal retry attempts made in the current dunning sequence.

activatedAt

string<date-time>

When the subscription first became active.

cancelledAt

string<date-time>

pausedAt

string<date-time>

suspendedAt

string<date-time>

startAt

string<date-time>

Deferred start, when creation set a future startAt.

cyclesCompleted

integer

Number of billing cycles charged so far.

completedAt

string<date-time>

When the subscription reached maxBillingCycles.

parentSubscriptionId

string

Parent subscription UUID, for add-on hierarchies.

propagateLifecycle

boolean

Whether pause/cancel on the parent cascades to this subscription.

pendingPlanId

integer

Plan the subscription will switch to at the next cycle, set by a next_billing change-plan.

createdAt

string<date-time>

updatedAt

string<date-time>

plan

object

A reusable billing plan. amount is a flat integer in the currency minor units (with separate currency + exponent) - not an Amount object.

Show child attributes

Payments

Tokenization

Subscriptions

Subscription Plans

SDK Session

Upgrade or Downgrade a Subscription

Response

Errors

Authorizations

Path Parameters

Body

Response

​Response

​Errors

Authorizations

Path Parameters

Body

Response

Response

Errors