@kodekloud: System Design: Building a Bulletproof Payment Gateway! 🚀 Basic payment setups fail during network timeouts. To block catastrophic duplicate charges, enforce client-generated idempotency keys (UUIDs). The server saves this key first; if a duplicate request arrives, it immediately returns the cached result instead of re-charging the buyer. Never overwrite database rows to update payment statuses. Instead, implement an immutable ledger where every state change—authorized, captured, or refunded—creates a brand-new row. Securely ingest asynchronous updates using signed webhooks, validating event IDs before appending them to the timeline. This design writes intents to the ledger before calling the API, shields endpoints with idempotency keys, and uses webhooks to build a flawless, fully auditable financial history. #SystemDesign #SoftwareArchitecture #PaymentGateway #Stripe #BackendDevelopment #Microservices #FinTech #Database #Idempotency #Webhooks #TechTips #codingforkids
KodeKloud
Region: TH
Wednesday 27 May 2026 15:45:00 GMT
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Reo Trawndres :
Can you make it into a prompt for claude? ✨
2026-05-28 08:08:42
161
Obinna Victor :
I think this design needs a bit more high-level system thinking.
UUID is fine, but it’s not the core idea. Idempotency is about same request = same result. If the key is random every time, retries can still lead to duplicates if the client regenerates it.
That’s why many production systems lean toward deterministic keys (like order_id or transaction reference) when possible, rather than relying purely on UUIDs.
Also, for real-world fintech systems, webhooks alone aren’t enough. They’re useful for near real-time updates, but they’re not 100% reliable they can be delayed, retried, or even missed.
Reconciliation is what guarantees correctness. It’s where you periodically verify your system state against the payment provider and resolve inconsistencies.
In practice, strong systems use both:
Webhooks for speed (real-time signals)Ronciliation for correctness (eventual consistency and recovery)
2026-05-29 13:46:10
36
Ellix🎙️ :
Can't I just use a third party system to run payments and then charge the customer card processing fee?
2026-06-26 17:47:19
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Tom :
Two kinds of people here 1- employed developers with experience. 2 - vibe coders trying to learn.
2026-05-31 12:44:45
66
Temma :
I disagree on having different rows for each state. The Stripe API provides a "payment_intent" key that can be queried at any time to get the state of the payment. Stripe takes care of the overhead.
2026-05-28 17:49:36
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Bideshi :
Wouldn't a network error that triggers two payments just trigger the generation of a new idemlotency key?
2026-05-28 12:39:52
10
Kryptonite :
Stripe takes care of idempotent key for payment. Stripe will not send multiple webhooks if acknowledged. Backend will just have to verify the webhook ID.
2026-05-28 12:59:23
19
Mornyn Glory :
Bro, I need your help with my Apple dev enrollment. I have my money but them no Dey mind me.
2026-06-24 01:10:16
1
Gideon Valor :
please bring me back...I'm building a startup
2026-06-16 18:48:48
7
Peter SKC :
storing all stages of a txn in a db will quickly result in a lot of rows, xn rows, for x stages, n transactions, i would rather have a saparate table/log.file audit trail, where the payments events are persisted and keep the transaction table cleaner
2026-06-03 18:22:51
3
OMZSI :
the best approach is v4 and it's mostly a combination of all the other methods
2026-06-21 11:27:51
1
Ridwanul Hoque Kawsar :
programming
2026-06-25 14:50:49
0
Aleksandar Vučenić :
if you wish to make an apple piefrom scratch, first you need to invent universe
2026-05-31 06:05:29
0
Arashi :
bro pls can you do a video on o paystack instead of stripe pls
2026-05-28 17:55:59
5
nickname :
a ledger has nothing to do with payment status
2026-05-27 17:24:40
3
cybarian :
Follow for follow back
2026-06-21 08:48:28
0
Herampto :
Tks. Help me a lot!!!
2026-06-21 02:12:37
0
Chika Emeche :
very insightful content 🥰
2026-05-28 17:45:31
1
maaaaarifer :
You need callback/webhook to verify the transaction, I work in fintech company.
2026-06-03 00:52:48
0
H⃞ a⃞H⃞ a⃞⚡️💯 :
Why are u building it from scratch let's start there
2026-06-15 21:30:45
0
What's Buzzn Nigeria :
idempotency is what I need
2026-06-10 16:50:10
0
Dony :
really good content
2026-05-28 18:15:20
0
DIgital Solutionist :
I don't see the need to keep each status of the transaction separately
2026-06-10 08:49:15
0
Gizzy2x :
i love these very informative things when im in the process of building my app. Tiktok show me more
2026-06-05 11:01:19
0
Matson :
Usefull
2026-05-27 17:09:09
0
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