Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx skills add roedyrustam/vibes-plug --skill payment-gateway-expertgit clone --depth 1 https://github.com/roedyrustam/vibes-plugWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/skills/roedyrustam/vibes-plug/payment-gateway-expert)<a href="https://agentmods.dev/skills/roedyrustam/vibes-plug/payment-gateway-expert"><img src="https://agentmods.dev/badge/skills/roedyrustam/vibes-plug/payment-gateway-expert/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/skills/roedyrustam/vibes-plug/payment-gateway-expert"><img src="https://agentmods.dev/badge/skills/roedyrustam/vibes-plug/payment-gateway-expert.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector pass
What it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00051 | $0.02323 |
| Opus 5.5 | $0.00020 | $0.00929 |
| Sonnet 5.5 | $0.00010 | $0.00465 |
| Haiku 4.5 | $0.00005 | $0.00232 |
Grade A, and why
payment-gateway-expert scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 4d ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
How it starts
The opening of the file, as written. The whole thing — 178 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Payment Gateway Expert / Ahli Payment Gateway
English
Orchestration & Integration
- Gateways & Payment Integrations:
doku-payment-gateway,saas-billing,agentic-m2m-settlement,agentic-micro-economy-architect - AI Agentic Commerce & MCP:
doku-mcp-server,mcp-server-architect,ai-llm-integration-expert - Database & Atomic Idempotency:
database-orm-expert,saas-multi-tenant - Security & Post-Quantum Crypto:
post-quantum-crypto-migrator,zero-trust-secret-vault,autonomous-red-teamer - Background Jobs & Observability:
async-queue-temporal-expert,data-telemetry-expert - Lifecycle & Governance:
brainstorming,zero-to-prod-orchestrator,session-memory-manager,anti-slop
Description
Expert guide for integrating major payment gateways (Stripe, PayPal, Xendit, Midtrans, DOKU SNAP BI) into modern SaaS platforms. Covers checkout flows, secure raw-body webhook handling, atomic idempotency to prevent race conditions, subscription state machines, and local database synchronization.
Core Principles
- Security First: Always validate webhook signatures using the raw, unparsed request body before processing any payment event. Never trust client-side data for prices or payment status. For Indonesian gateways (DOKU, Midtrans, Xendit), accurately apply the required signature protocol: DOKU Checkout uses HMAC-SHA256 with body Digest, while SNAP BI Direct APIs enforce HMAC-SHA512 with ISO8601 timestamps.
- Idempotency & Race Condition Prevention: Implement idempotency keys for all payment creation requests. For webhook ingestion, DO NOT rely solely on
findUniquechecks, as concurrent webhook retries cause race conditions. Always use Atomic Updates (UPDATE ... WHERE status = 'PENDING') or database pessimistic locks (SELECT ... FOR UPDATE). - Raw Body Ingestion: Webhook signature verification fails if JSON is parsed or re-serialized with modified key ordering. Extract the exact raw string buffer (
req.text()in Fetch API orexpress.raw({ type: 'application/json' })in Express). - Early 200 OK Acknowledgment: If a webhook event is verified but already processed, immediately return
200 OKso the payment gateway halts retries. - State Synchronization: Ensure the local database (e.g., PostgreSQL, Supabase via Drizzle/Prisma) is updated transactionally upon receiving successful webhook events.
- Subscription Management: Map provider subscription statuses (
trialing,active,past_due,canceled) accurately to internal SaaS state machines.
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 4d ago Changed · +6 lines 4ad765cb16bb
- 5d ago Changed · +1 lines 0d38c80b8173
- 8d ago Changed · +39 lines 843a3aa21b10
- 17d ago Changed 40ab64082d58
- 22d ago Changed 1ce13b6d3a4e
- 23d ago Changed b9529be2fd9e
- 1mo ago Changed · +2 lines · +2 tokens per session 8a3ec260115f
- 1mo ago Changed ba0a62438d6a
- 1mo ago Changed 1de585f3f5d0
- 1mo ago First seen · 130 lines · 49 tokens per session scan A abd2dafd1ded
payment-gateway-expert is a skill published in the GitHub repository roedyrustam/vibes-plug (113 stars, last pushed yesterday), licensed MIT. It adds 51 tokens to every session and 2,323 once invoked, about $0.0002 per session on Opus 5.5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-09-03.
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dunning-escalation
Per-subscription dunning ladder for recovering failed Stripe payments — smart retry, payment reminder, update-your-card notice, final notice — with minimum wait times between rungs, the ledger format that carries state across hourly runs, and the stop-for-human line at cancellation, credits, and refunds.
Braintree Automation
Braintree Automation: manage payment processing via Stripe-compatible tools for customers, subscriptions, payment methods, and transactions.