Payments migration

Polar → Stripe Billing

Move products, prices, customers, payment methods, subscriptions, invoices, tax settings, webhooks, entitlements, and financial evidence from Polar into Stripe Billing with an explicit exception ledger and evidence-based cutover.

Typical timeline20–45 business days90–170 hours active work

Statusneeds review

Source testedPolar documentation reviewed 2026-07-19

Destination testedStripe Billing documentation reviewed 2026-07-19

Last reviewed2026-07-19

Sources2

Before you migrate

Should you make this move?

Both platforms have a case. Compare what you gain with what you give up before scheduling the cutover.

Current platform

Polar

Reasons to stay

Developer-focused products, benefits, subscriptions, and merchant-of-record billing fit software creators
Checkout, subscriptions, tax, and customer records are consolidated

Reasons to leave

Its younger ecosystem and narrower commerce scope may not cover complex businesses
Billing state and compliance responsibilities make switching unusually sensitive

New platform

Stripe Billing

What gets better

Flexible APIs, pricing models, and ecosystem integrations support sophisticated billing
Checkout, subscriptions, tax, and customer records are consolidated

What gets worse

The seller retains tax, compliance, fraud, and substantial implementation responsibility
Billing state and compliance responsibilities make switching unusually sensitive

Best of the move

Stripe Billing: Flexible APIs, pricing models, and ecosystem integrations support sophisticated billing. This removes a major source-side concern: Its younger ecosystem and narrower commerce scope may not cover complex businesses.

Worst of the move

What you lose: Developer-focused products, benefits, subscriptions, and merchant-of-record billing fit software creators. What you inherit: The seller retains tax, compliance, fraud, and substantial implementation responsibility.

01At a glance

Know the shape of the move.

Transfer outcome12 features audited

Clean0

Partial7

Manual5

Lost0

Mapping route9 of 9 fields have a destination path

SourcePolar9 mapped fields

Automatic0

Transform6

Manual3

Unsupported0

DestinationStripe Billing9 supported paths

This timeline assumes

Up to 500,000 customers, 100,000 subscriptions, and five years of billing evidence
Both providers approve the customer and payment-method transfer path in writing.
Finance and legal owners approve the merchant, tax, invoice, and customer-notice change.
The application can process both providers idempotently during a controlled transition.
The migration team records evidence for every blocking verification check.

02Loss matrix

What survives the move.

“Partial” and “manual” are not footnotes. They are work that must be scheduled and verified.

Item	Outcome	Impact	What happens	Mitigation
Products, prices, customers, subscriptions, invoices, and selected billing state	partial	critical	Core products, prices, customers, subscriptions, invoices, and selected billing state can move, but Polar and Stripe Billing use different models, limits, identifiers, and import behavior.	Pilot every feature class, preserve source IDs, and reconcile accepted, transformed, rejected, and excluded items.
Payment-method portability, tax, retries, entitlements, webhooks, and financial history	manual	critical	Polar-specific runtime configuration and historical evidence do not become native Stripe Billing behavior through the core data transfer.	Inventory every active dependency, approve its destination disposition, and test the replacement before source writes stop.
Products, prices, and plans	partial	critical	Catalog objects can map while IDs, tax behavior, currencies, intervals, and grandfathered pricing differ.	Create and sign a price map before customer migration.
Customers and billing profiles	partial	critical	Core identities can move while addresses, tax IDs, metadata, balances, and duplicates require review.	Preserve source IDs and reconcile one destination customer per approved identity.
Payment methods	partial	critical	Card or wallet portability requires a PCI-compliant provider-to-provider transfer and some methods cannot move.	Obtain written scope from both providers and define reauthorization cohorts.
Active subscriptions	partial	critical	Status, next billing date, items, quantities, trials, cancellation, and discounts need exact import behavior.	Pilot every lifecycle state and reconcile the first renewal.
Invoices, charges, refunds, and disputes	partial	critical	Historical financial objects may remain read-only in the source.	Archive signed ledgers and define which destination records are reference-only.
Coupons, credits, and balances	partial	high	Redemption state, customer credits, and proration semantics differ.	Reconcile monetary liabilities before cutover.
Tax, merchant-of-record, and invoices	manual	critical	The legal seller, invoice issuer, tax collection, and filing responsibility can change.	Get finance and legal approval for the cutover date and customer notice.
Dunning, retries, and failed payments	manual	critical	Recovery schedules and past-due states do not continue automatically.	Let source dunning settle or map every exception explicitly.
Checkout, portal, and customer communications	manual	critical	Hosted URLs, authentication, receipts, and lifecycle email templates change.	Test every customer-facing billing path.
Webhooks and application state	manual	critical	Event names, ordering, retries, IDs, and signatures differ.	Build idempotent dual-provider handling and reconcile events.

03Field and feature mapping

Where each thing goes.

Source	Destination	Method	Notes
Polar product and price	Stripe Billing product and price	transform	Preserve source IDs and grandfathered price intent.
Customer	Destination customer	transform	Map identity, address, tax, metadata, and balance.
Payment method	Destination payment method or reauthorization	manual	Requires provider-approved PCI transfer.
Subscription	Destination subscription	transform	Map status, period, items, quantity, trial, and cancellation.
Invoice or charge	Destination reference record or archive	transform	Do not make history chargeable.
Coupon, credit, or balance	Destination discount or liability	transform	Reconcile monetary exposure.
Dunning state	Destination recovery state	manual	Avoid moving ambiguous in-flight retries.
Webhook event	Destination event and application transition	transform	Build idempotent handlers.
Checkout or portal URL	Destination checkout or portal	manual	Replace every customer-facing link.

04Before you begin

Make the move recoverable.

Backup procedure

Create the source-of-truth backup

Preserve Polar data, configuration, and operating evidence before any destination write.

Export Polar products, prices, customers, subscriptions, invoices, charges, refunds, disputes, discounts, events, and reports.
Inventory payment methods, lifecycle states, retries, webhooks, tax, checkout, portal, and application IDs.
Record signed counts, MRR, balances, renewal schedules, monetary totals, and exception cohorts.
Hash exports and secure provider correspondence.

Proof to capture: A signed manifest reconciles every scoped record class, runtime dependency, export file, count, and hash.

Transformation · Provider templates and migration ledger

Catalog and subscriber state map

Preserve pricing, renewal, tax, and application entitlement intent.

Inventory source values and exceptions.
Define explicit destination mappings.
Reject unmapped critical records.

Proof to capture: Save the input, output, command or tool settings, warnings, and final item counts.

Transformation · Sandbox accounts, webhook simulator, and finance reports

Dual-provider event harness

Prove checkout, webhooks, renewal, recovery, refunds, and reconciliation.

Normalize encoding, dates, identifiers, and blanks.
Run a representative pilot.
Reconcile accepted, rejected, and transformed rows.

Proof to capture: Save the input, output, command or tool settings, warnings, and final item counts.

05Handle with care

The things most likely to hurt.

These are operating limits. Treat every “Stop if” condition as a blocked migration, not a suggestion.

Transfer

Payment methods do not arrive for every cohort

criticalpossible likelihood

Unsupported methods or provider mismatches leave subscriptions unable to renew.

Consequence: Customers churn or require emergency reauthorization.
Mitigation: Obtain transfer scope and segment unsupported methods before cutover.

Stop if: Any cohort lacks a renewal path and communication.

Cutover

Both providers renew subscriptions

criticalpossible likelihood

Source cancellation and destination activation are not atomic.

Consequence: Customers are charged twice.
Mitigation: Use an agreed import date and reconcile every source and destination state.

Stop if: Any test or live customer has two billable subscriptions.

Webhooks

Application entitlements drift from billing

criticalpossible likelihood

Imported or new event semantics are processed incorrectly.

Consequence: Customers gain or lose access improperly.
Mitigation: Use idempotent handlers and compare billing state to application state.

Stop if: Any critical entitlement invariant fails.

06Precise timeline

Do the work in this order.

Estimate forUp to 500,000 customers, 100,000 subscriptions, and five years of billing evidence

Total elapsed20–45 business days

Active work90–170 hours

BufferAdd time for large exports, unsupported Polar features, destination limits, identity exceptions, regulated data, or strict downtime requirements.

Days 1–3Inventory and decisions2–3 days

Days 3–5Backup and reconcile1–3 days

Days 5–12Map and pilot3–8 days

Days 10–20Final delta and switch1–5 days

Days 12–40Observe and close3–10 days

1
Days 1–3 · inventory
Inventory and decisions
6–12 hours active2–3 days elapsedOwner review waiting
- Inventory Polar data, features, users, domains, and integrations.
- Approve scope, owners, mappings, and exclusions.
Depends on: Polar and Stripe Billing administrator access
Stop / go checkpoint
Export?
Go when: Every critical item has an owner and disposition.
Stop when: Consent, billing, access, or system ownership is unclear.
2
Days 3–5 · backup
Backup and reconcile
5–10 hours active1–3 days elapsedExport processing waiting
- Create immutable exports and configuration evidence.
- Reconcile counts, totals, and hashes.
Depends on: Approved inventory
Stop / go checkpoint
Transform?
Go when: Source totals and export manifests agree.
Stop when: Any critical dataset or configuration is absent.
3
Days 5–12 · pilot
Map and pilot
10–35 hours active3–8 days elapsedDestination processing and review waiting
- Configure Stripe Billing and transform representative data.
- Run a pilot containing normal records and every critical edge case.
Depends on: Verified backup
Stop / go checkpoint
Scale?
Go when: Pilot mappings, behavior, access, and evidence pass.
Stop when: Any critical check fails or produces unexplained variance.
4
Days 10–20 · cutover
Final delta and switch
5–25 hours active1–5 days elapsedDNS, import, or sync propagation waiting
- Freeze production writes in Polar.
- Apply the final delta, switch ownership, and run blocking checks.
Depends on: Passed pilot and approved rollback
Stop / go checkpoint
Open production?
Go when: Counts reconcile and one destination system owns production.
Stop when: A source writer remains active or a blocking check fails.
5
Days 12–40 · observe
Observe and close
3–18 hours active3–10 days elapsedOperating-cycle evidence waiting
- Monitor one complete operating cycle.
- Sign the verification report and close rollback only after stability.
Depends on: Verified cutover
Stop / go checkpoint
Close rollback?
Go when: No trigger occurs during the agreed observation period.
Stop when: Data, access, delivery, routing, or business results regress.

07The point of change

Cut over with a way back.

Go live

Cutover

Make Stripe Billing the only production system without losing the final Polar delta.

Recommended window: A low-volume weekday morning with platform, data, DNS, and business owners available.

Freeze production writes and scheduled actions in Polar.
Export, transform, and reconcile the final delta.
Apply the approved delta to Stripe Billing.
Switch domains, forms, integrations, sending, or sync ownership as applicable.
Run every blocking verification check and keep the source intact.

Proof to capture: Stripe Billing owns production, totals reconcile, and every blocking check has durable evidence.

Return to safety

Rollback

Return production ownership to Polar without losing destination-era changes.

Deadline: Within seven days and before source data, plans, credentials, domains, or billing are changed.

Stop new writes and scheduled actions in Stripe Billing.
Restore the prior Polar routing, forms, integrations, sending, or sync ownership.
Export the Stripe Billing post-cutover delta.
Review and apply safe destination-era changes to Polar.
Run the same blocking checks against the restored source.

Proof to capture: Polar again owns production with current data and no duplicate destination action.

Rollback immediately when

Unexplained critical count or value variance
Missing or exposed critical data
Duplicate production action
Failed access, routing, delivery, or integration check
A critical feature has no safe destination replacement

08Verification report

Prove the migration worked.

Every blocking check must pass. Capture the evidence before cleanup begins.

ID	Check	Method	Expected result	Evidence
`V-01`Blocking	Product and price mapping	Compare currency, interval, tax behavior, and grandfathered cohorts.	Every billable price has one approved destination.	Price map.
`V-02`Blocking	Identity reconciliation	Compare source, transfer, rejected, and destination customers.	Every customer is accounted for without unexplained duplicates.	Customer ledger.
`V-03`Blocking	Payment-method coverage	Reconcile transferred and reauthorization cohorts by method.	Every renewable customer has a valid path.	Method report.
`V-04`Blocking	Lifecycle state parity	Compare status, items, quantity, period, trial, cancellation, discount, and next charge.	Every subscription state matches the signed map.	Subscription ledger.
`V-05`Blocking	Monetary totals and liabilities	Reconcile MRR, credits, balances, refunds, disputes, and renewal schedule.	All signed totals match or have approved explanations.	Finance sign-off.
`V-06`Blocking	Webhook and entitlement behavior	Replay success, renewal, failure, recovery, change, refund, and cancellation.	One idempotent application transition per event.	Webhook evidence.
`V-07`Blocking	Checkout, portal, invoice, and email	Exercise every customer-facing billing path.	Access, amounts, tax, and communication are correct.	Journey matrix.
`V-08`Blocking	Single billing authority	Inspect provider states, schedules, checkouts, and application routing.	Stripe Billing alone owns approved new charges and renewals.	Cutover checklist.

09Post-migration cleanup

Remove the scaffolding safely.

Safe after: One complete operating cycle, at least seven stable days, and owner sign-off on every blocking check.

Create final Polar exports and archive verification evidence.
Revoke temporary credentials, API keys, webhooks, and elevated roles.
Remove obsolete embeds, forms, jobs, integrations, and DNS records.
Keep the source intact through the approved retention window.
Cancel paid plans only after billing, legal, and recovery review.
Schedule the next Stripe Billing backup, access, and migration-playbook review.

Sources and maintenance

Built to be reviewed.

Tested 2026-07-19. Next scheduled review: 2026-10-19.

Polar: official migration documentationAccessed 2026-07-19
Stripe Billing: official migration documentationAccessed 2026-07-19

Know the shape of the move.

This timeline assumes

What survives the move.

Where each thing goes.

Make the move recoverable.

Create the source-of-truth backup

Catalog and subscriber state map

Dual-provider event harness

The things most likely to hurt.

Payment methods do not arrive for every cohort

Both providers renew subscriptions

Application entitlements drift from billing

Do the work in this order.

Inventory and decisions

Export?

Backup and reconcile

Transform?

Map and pilot

Scale?

Final delta and switch

Open production?

Observe and close

Close rollback?

Cut over with a way back.

Cutover

Rollback

Prove the migration worked.

Remove the scaffolding safely.

Built to be reviewed.