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Vibe Coding · Lesson

Managing Subscriptions

Handle plans and renewals.

Managing Subscriptions is a free Vibe Coding lesson on CoddyKit — lesson 3 of 4. You can read the complete lesson below for free — then practise it hands-on in the browser with a built-in code editor and a 24/7 AI tutor. It is part of the Vibe Coding learning path, one of 4 lessons in the course, and your progress syncs across the web and the CoddyKit app.

Subscriptions Carry State

A subscription is not a single charge — it is an ongoing relationship that lives in time. It has a status, a current period, and a billing schedule that the provider advances automatically.

Your job is to mirror that state in your own database so your app always knows whether a given user is currently entitled to paid features.

The Status Machine

A subscription moves through states: trialing, active, past_due, canceled, and unpaid. Each transition has consequences for access.

Model this explicitly. Treat "active" and "trialing" as entitled, "past_due" as a grace window, and "canceled" or "unpaid" as revoked. Hard-coding a single boolean throws away information you will need.

List every subscription status Stripe can report (trialing, active, past_due, canceled, unpaid, incomplete) and tell me, for each, whether my app should grant or revoke access to paid features. Put it in a decision table.

Entitlements, Not Flags

Resist sprinkling "if user.paid" everywhere. Centralize a single function that answers "what is this user entitled to right now?" based on their subscription state.

This entitlement check becomes the one place your access logic lives. Change a rule once and the whole app obeys it.

Write a single getEntitlements(userId) function that reads the stored subscription status and plan, and returns the feature set the user can access. Make every feature gate in the app call this one function instead of checking raw flags.

Trials

A trial grants access before the first charge. The subscription exists in a trialing state; at trial end the provider attempts payment and flips to active or past_due.

Decide whether trials require a card up front. Card-up-front reduces abuse but lowers signups; card-free is friendlier but invites tire-kickers.

I want a 14-day free trial. Compare requiring a card up front versus no card at all: conversion, abuse, and the webhook events I need to handle when the trial ends and the first real charge succeeds or fails.

Upgrades and Downgrades

Customers switch plans mid-cycle. Upgrades usually take effect immediately with a prorated charge for the remaining period. Downgrades often apply at the next renewal to avoid refunds.

Proration is the math of crediting unused time and billing the difference. Let the provider compute it; your job is to choose the timing policy.

Explain proration when a user upgrades from the $10 plan to the $30 plan halfway through a billing month. Show how Stripe handles the credit and charge, and recommend whether downgrades should be immediate or deferred to period end.

Cancellations

Cancelling rarely means instant cutoff. The standard pattern is cancel_at_period_end: the user keeps access until the period they already paid for runs out, then it lapses.

This avoids refund disputes and respects what the customer paid for. Reflect both the cancellation request and the actual lapse in your state.

Implement cancellation as cancel_at_period_end so the user keeps paid access until the end of the current period, then loses it. Show which webhook tells me the subscription actually ended versus merely being scheduled to cancel.

Failed Renewals and Dunning

Cards expire and fail. When a renewal fails, the subscription goes past_due and the provider retries on a schedule — this recovery process is called dunning.

During dunning you can keep access (grace) or restrict it. Send the customer emails to update their card. Decide your grace policy explicitly.

Set up dunning for failed subscription renewals: configure Stripe's retry schedule, decide a 3-day grace period where access continues, and send the customer a card-update email. List the webhook events that drive each step.

Keeping Your DB in Sync

The provider is the source of truth, but querying it on every request is slow. Instead, cache the subscription state in your database and update it whenever a webhook arrives.

Every relevant event — created, updated, deleted, payment_failed — should write the new status to your record. Your app then reads its own fast, local copy.

Design a subscriptions table that mirrors Stripe state (status, plan, current_period_end, cancel_at_period_end). Write the webhook handler that updates this row on customer.subscription.created, updated, and deleted so my app reads its own copy.

The Customer Portal

Building a self-service billing UI is a lot of work. Most providers offer a hosted customer portal where users update cards, switch plans, view invoices, and cancel.

You generate a portal link from your server; the provider handles the rest and emits webhooks for any changes the user makes. This saves weeks of UI work.

Add a "Manage Billing" button that calls my server to create a Stripe Billing Portal session for the logged-in customer and redirects them there. Confirm that plan changes they make in the portal come back to me as webhook events.

Grace, Reactivation, and Edge Cases

Real life is messy: a past_due user pays late and should regain access; a canceled user resubscribes; a refund reverses a charge. Each must update entitlements correctly.

Drive every change through the same status-to-entitlement logic. If reactivation flips status back to active, access should restore automatically with no special-case code.

Testing Subscription Lifecycles

Use test clocks or simulated events to fast-forward time: start a trial, end it, fail a renewal, recover, then cancel. Verify entitlements at every step.

Subscriptions fail in the future, not at checkout. Testing the full lifecycle is the only way to catch a renewal bug before a customer does.

Use Stripe test clocks to simulate a full subscription lifecycle: trial start, trial end with successful charge, a failed renewal that goes past_due, recovery, and finally cancellation. For each phase, tell me what my entitlement check should return.

Quick Check

Confirm the cleanest way to manage access logic.

Recap

Subscriptions are stateful relationships with a status machine: trialing, active, past_due, canceled, unpaid. Centralize access in one entitlement function so every gate obeys the same rule, and cache provider state in your DB via webhooks instead of polling.

Handle trials, prorated upgrades, period-end cancellations, and dunning for failed renewals. Offer a hosted customer portal to save UI work, and test the entire lifecycle with test clocks before launch.

Frequently asked questions

Is the “Managing Subscriptions” lesson free?

Yes — the full text of “Managing Subscriptions” is free to read here on the web, and the Vibe Coding course includes 4 lessons in total. To practise it interactively (a built-in code editor and a 24/7 AI tutor) and unlock the rest of the Vibe Coding course, upgrade to CoddyKit PRO.

What will I learn in “Managing Subscriptions”?

Handle plans and renewals. You practise Vibe Coding with hands-on code you run directly in the browser, and a 24/7 AI tutor answers your questions as you work through the lesson.

Do I need any experience to start Vibe Coding?

No prior experience is required. Vibe Coding on CoddyKit is structured for beginners through advanced learners; this is — lesson 3 of 4, so you can start here or from the beginning and move at your own pace.

How long does the “Managing Subscriptions” lesson take?

Most CoddyKit lessons take about 5–10 minutes. Each one is bite-sized and interactive, so you make steady progress and pick up exactly where you left off across the web and the app.

Can I write and run code in this Vibe Coding lesson?

Yes. Every Vibe Coding lesson includes a built-in code editor, so you write and run real code right in your browser and get instant AI feedback — no local setup required.

All lessons in this course

  1. Payment Concepts
  2. Setting Up a Checkout
  3. Managing Subscriptions
  4. Verifying Payments Safely
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