Stripe Makassar Community • SEA Builders Series

Payment architecture for credit-based AI and SaaS products.

Technical depth for developers, practical payment thinking for founders, and real implementation lessons from building credit-based AI and SaaS products with Stripe.

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For developers and founders

The code is technical. The problem is commercial.

SEA Builders Series goes into implementation details, but the goal is simple: help builders design products that can charge, fulfill, recover, and scale more safely. Credits, webhooks, refunds, and async jobs are not only backend details. They affect user trust, pricing flexibility, revenue reporting, and support load.

Developers will get concrete implementation patterns for credits, webhooks, idempotency, async jobs, and settlement.

Founders will get a clearer mental model for why payment architecture matters before a product reaches real usage.

If credits are granted twice

Users can receive free balance, your revenue numbers become noisy, and support has to clean up state manually.

If failed jobs are not refunded

Customers lose trust because they paid or spent credits for work that never completed.

If payment events are handled casually

Retries, duplicate webhooks, and out-of-order events can break product access right after payment.

If the billing model is too rigid

It becomes harder to experiment with subscriptions, credit packs, usage-based pricing, trials, and global customers.

About the series

Practical payment lessons from real systems, not generic API tours.

A lot of builders start with Checkout. The harder questions appear later: what happens after payment succeeds but the async job has not finished, when webhooks retry, when jobs fail, or when pricing evolves from one-time purchases into credits, subscriptions, and usage-based models.

The early sessions use BabySea's open-source work as reference material because these are problems we have actually worked through while building credit-based infrastructure. The patterns are not specific to BabySea; they apply to AI apps, SaaS products, devtools, render workloads, exports, batch jobs, and other credit-based products.

The first three workshops run online and focus on implementation. The fourth session is an offline Makassar meetup for developers, founders, startup operators, and local builders thinking about global products.

The questions each workshop answers

How do you avoid charging users unfairly when an async job fails?

Reserve credits before dispatch, then charge on success or refund on failure with transactional ledger writes.

How do you prevent duplicate credits when Stripe retries a webhook?

Use webhook signature verification, a processed event table, and SQL-level idempotency gates.

How do you recover stuck balances before they become support tickets?

Detect orphaned reservations and refund them idempotently without racing the success path.

How do you keep pricing flexible as the product grows?

Design credits, subscriptions, one-time packs, and usage events around a ledger that remains authoritative.

How do you keep the client, Stripe, and background jobs from disagreeing?

Move balance mutations behind backend-only functions and make the database the settlement authority.

Program schedule

Technical depth for developers, practical payment thinking for founders.

Three online workshops go deep on credit ledger design, Stripe webhook safety, and async job settlement. The fourth session in Makassar brings the community together.

Series 01

Technical workshop

Online

Designing credit systems that do not lose money or break user trust

Build the ledger for prepaid credits, charges, and refunds.

A practical workshop on the credit ledger behind a paid product: balances, immutable ledger rows, prepaid grants, reservations before work starts, terminal charges, and refunds when work fails.

Why it matters

Founders will understand how credit mistakes become revenue leakage, unfair charging, and support burden. Developers will learn the database patterns that make the balance authoritative.

Topics

Prepaid credit balances and immutable ledger history
Reserve before dispatch, charge on success, refund on failure
Atomic balance updates that prevent overdrafts
Idempotent reserve, charge, and refund operations
Backend-only balance mutations
How credit correctness affects user trust and monetization

Recommended for

Developers building credit-based products
Technical founders designing paid usage flows
Teams replacing ad-hoc balance columns
Builders using Stripe with Supabase or Postgres

Audience: Developers, technical founders, and product-minded builders

Series 02

Technical workshop

Online

Making Stripe webhooks safe for real payments and reliable product fulfillment

Prevent duplicate credits, missed fulfillment, and retry-related bugs.

A workshop on what happens after payment succeeds: verifying Stripe events, processing webhooks safely, granting credits once, and keeping product access aligned with payment state.

Why it matters

Founders will see why webhook reliability directly affects customer trust, paid access, and manual support load. Developers will implement the idempotency layer that keeps fulfillment safe under retries.

Topics

Stripe webhook verification and raw request bodies
Processed event tables and duplicate delivery handling
Checkout and invoice event
Additive credit grants that never reset balances
Mapping Stripe customers to internal accounts
Operational boundaries for refunds, disputes, and clawbacks

Recommended for

Developers shipping Stripe webhook handlers
Founders with paid products or credit packs
Teams with subscription + credit-pack models
Anyone who wants fewer payment fulfillment bugs

Audience: Developers integrating Stripe and founders reviewing fulfillment risk

Series 03

Technical workshop

Online

Charging fairly for async jobs that can fail, retry, or timeout

Reserve, charge, refund, and recover async jobs safely.

A deeper workshop on separating payment state from work state when jobs can timeout, crash, return partial output, or finish out of order. We will walk through the lifecycle needed to keep user balances correct.

Why it matters

Founders will understand how async failure modes affect margin, refunds, trust, and support. Developers will learn the settlement lifecycle behind reliable paid async work.

Topics

Payment state vs. work state
Reserve before dispatch, charge on confirmed success
Refund failed, timed-out, or cancelled work
Guard against charge-after-refund and refund-after-charge cases
Recover orphaned reservations safely
Apply the pattern to AI, render, export, and batch workloads

Recommended for

AI app developers
Backend developers operating long-running workloads
Founders building usage-based or credit-based products
Teams dealing with stuck jobs, retries, or support tickets

Audience: Developers running async workloads and founders building usage-based products

Series 04

Community meetup

Makassar

From local product to global payments and customers

A Makassar meetup for builders going global.

An offline community meetup for developers, founders, local Stripe users, startup operators, and student builders to share lessons, questions, and practical notes on building products for global customers.

Why it matters

This session connects the technical workshops to broader startup questions: pricing, trust, global customers, payment methods, product readiness, and moving from prototype to production.

Topics

Building from Indonesia
Accepting payments from global customers
Pricing and trust signals for international users
Checkout experience and payment methods
Founder and developer lessons from local builders
Community demos, Q&A, and networking

Recommended for

Makassar builders
Local founders and startup operators
Developers building global software products
Students and early builders interested in startups

Audience: Developers, founders, startup operators, and local builders

What you will learn

Six payment invariants that protect product trust and implementation correctness.

Every credit-billed product eventually meets the same failure modes: duplicate webhooks, double-clicks, out-of-order terminal events, crashed jobs, renewals that interact with credit packs, and balance writes from the wrong boundary. The workshops translate each failure mode into a product risk and an implementation pattern.

Atomic reserve, charge, refund

Founder meaning: Users are not charged for failed work, and your product has a fair lifecycle for paid usage.

Developer pattern: Implement reserve→charge→refund with a single UPDATE ... WHERE credits >= cost check-and-deduct, so concurrent requests cannot overdraw the balance.

SQL-level idempotency

Founder meaning: Stripe retries do not accidentally grant credits twice or create confusing billing state.

Developer pattern: Use processed event tables and unique constraints so duplicate Stripe and provider events are exactly-once at the database, not just the application.

Out-of-order event guards

Founder meaning: Your system remains correct even when success, failure, refund, or retry events arrive in the wrong order.

Developer pattern: Serialize terminal settlement with row locks and inspect prior ledger rows before mutating the balance.

Stripe webhook reconciliation

Founder meaning: Payments and product access stay aligned, so users receive what they paid for without manual cleanup.

Developer pattern: Verify webhook signatures, gate processed Stripe events, and grant credits additively so renewals never reset purchased credit packs.

Crash recovery for async jobs

Founder meaning: Stuck jobs do not become stuck balances, refund disputes, or avoidable support conversations.

Developer pattern: Run a recovery sweep that finds old reservations without terminal charge or refund rows, then refunds them idempotently against the success path.

Backend-only ledger boundary

Founder meaning: Users cannot manipulate balances from the browser, and the product has a clearer trust boundary.

Developer pattern: Protect credit tables with RLS, revoke direct client mutations, and route writes through server-side functions with a locked execution boundary.

Frequently asked questions

Practical workshops, not generic API tours.

The online sessions include code-level material for developers, but founders and product builders are welcome if they want to understand the architecture behind credits, subscriptions, async jobs, and monetization.

Who is this series for?

The first three sessions are built for developers, but founders and product builders are welcome. The goal is to connect payment architecture with product reliability, pricing flexibility, user trust, and revenue safety.

How technical are the workshops?

They are technical, but each session starts from the product problem before going into implementation. Developers will see code-level patterns; founders will understand why those patterns matter for charging, fulfillment, refunds, and support.

What stack do the workshops assume?

Stripe for payments, Postgres as the ledger authority, and a TypeScript backend in the reference starter. The patterns translate to other server runtimes and Postgres-backed applications.

Do I need to deploy anything before joining?

No. The walkthroughs reference the open-source ledger-fortress primitive and the generative-media-starter app, but you can follow the architecture and implementation without deploying anything before the session.

What experience do I need?

For developers, comfort with APIs, databases, webhooks, and server-side code will help. Prior Stripe experience is useful but not required. For founders, curiosity about pricing, billing, and product reliability is enough.

Is this only relevant to AI products?

No. AI is the running example because async failures are visible, but the settlement patterns apply to any credit-billed workload: AI generation, render jobs, exports, batch processing, developer tools, or usage-based SaaS.

Online or offline?

The first three technical workshops run online. The fourth event is planned as an offline community meetup in Makassar for developers, founders, and local builders.

Is this a BabySea product workshop?

No. BabySea open-source projects are used as reference material because these are problems we have actually worked through. The patterns are general and apply to many AI, SaaS, devtool, and credit-based products.

Will recordings and code be shared?

The reference code is public through ledger-fortress and generative-media-starter. Workshop materials and recordings will be shared with registrants when available.

Is SEA Builders Series an official Stripe program?

SEA Builders Series is organized by the host under Stripe Makassar Community, which is part of the Stripe Community Builders program.

Call to action

Join the SEA Builders Series.

Follow the full program across online technical workshops and the offline Makassar community meetup. Join as a developer who wants implementation patterns, or as a founder who wants a clearer payment architecture mental model.

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