Tool-pair integration pattern
Stripe + Loops integration (event-driven email)
Stripe + Loops is the event-driven indie SaaS email pattern. Stripe fires events (customer created, subscription updated, payment failed); a webhook bridge syncs the events into Loops as contact properties; Loops triggers email sequences based on the properties.
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Stripe owns (teardown →)
Source of truth for payment + subscription events, customer payment methods, billing lifecycle.
Loops owns
Email sequences (drip campaigns), broadcast sends, transactional email templates, contact properties + segmentation, automation logic.
Integration shape
Webhook bridge. Stripe sends events to your webhook; your code transforms each event into a Loops API call (createContact, updateContact, sendEvent). Loops sequences read contact properties to decide what to send.
Implementation steps
Step 1
Set up the Stripe webhook endpoint
Single endpoint in your Next.js app that receives all Stripe events. Verify signature; route by event type.
Gotcha: Same idempotency requirement as Stripe+Supabase: tolerate webhook replays.
Step 2
Define the Loops contact-property schema
Decide which Stripe-side data lives on the Loops contact. Typical: subscription_status, plan_name, current_period_end, has_paid_lifetime, churn_risk.
Gotcha: Too many properties become hard to maintain. Pick 5-10 that drive segmentation; let everything else live in Stripe.
Step 3
Map Stripe events to Loops API calls
customer.subscription.created → Loops createContact with plan_name. customer.subscription.deleted → Loops updateContact with subscription_status='churned'. invoice.payment_failed → Loops sendEvent (triggers dunning sequence).
Gotcha: Map all relevant events upfront; missing one means a sequence fires on stale data later.
Step 4
Build the Loops sequences
Welcome sequence (triggers on contact creation). Trial-end sequence (triggers on subscription.trial_will_end). Dunning sequence (triggers on payment.failed). Win-back sequence (triggers on subscription deleted).
Gotcha: Loops sequences run independently — make sure they do not overlap (a subscribed customer should not get the trial-end sequence after their first paid charge).
Step 5
Test each sequence end-to-end
For each Stripe event you trigger on, simulate the event (Stripe CLI works), verify Loops contact updates, verify the sequence fires.
Gotcha: Sequences that fire in test mode but not production usually trace back to webhook event mapping differences between modes.
Common gotchas across the whole integration
- Loops contact-update API has rate limits. Batch updates during high-volume Stripe event spikes (e.g. mass renewals).
- Multi-product SaaS needs Loops contact properties that distinguish products. 'plan_name' might be 'Product A Pro' or 'Product B Starter'; design accordingly.
- Email sequences that fire on every plan change can overwhelm customers. Throttle: most plan changes should not trigger sequences, only specific transitions (free→paid, paid→churned).
- The webhook bridge is mostly fire-and-forget, but Loops API failures need handling. Log Loops API errors; retry on transient failures.
When NOT to build this integration
If your email logic is simple (just welcome + receipts + occasional broadcasts), Resend + Stripe webhooks is simpler. The Stripe + Loops pattern shines once you have 4+ sequences and segmentation needs.
Frequently asked
- Should I use Loops or Customer.io for this?
- Loops for indie SaaS up to about 5,000 customers — better DX, simpler model, lower price. Customer.io once you need more advanced segmentation, multi-channel (SMS), or enterprise features.
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