{
  "checked_on": "2026-11-03",
  "sources": [
    {
      "id": "stripe",
      "title": "Stripe Ledger",
      "url": "https://stripe.dev/blog/ledger-stripe-system-for-tracking-and-validating-money-movement"
    },
    {
      "id": "migration",
      "title": "Stripe Online migrations at scale",
      "url": "https://stripe.com/blog/online-migrations"
    },
    {
      "id": "adyen",
      "title": "Adyen Design to Duty",
      "url": "https://www.adyen.com/knowledge-hub/design-to-duty-adyen-architecture"
    },
    {
      "id": "wise",
      "title": "Wise Engineering Kafka retry strategy",
      "url": "https://medium.com/wise-engineering/teamwork-implementing-a-kafka-retry-strategy-at-wise-82e0887e243b"
    },
    {
      "id": "monzo",
      "title": "Monzo data stack",
      "url": "https://monzo.com/blog/2021/10/14/an-introduction-to-monzos-data-stack"
    },
    {
      "id": "nu",
      "title": "Nubank log platform",
      "url": "https://building.nu.com/how-nubank-built-its-in-house-log-platform/"
    },
    {
      "id": "paypal",
      "title": "PayPal Gimel engineering publication",
      "url": "https://medium.com/paypal-tech/gimel-paypals-analytics-data-processing-platform-22ec5890f4af"
    },
    {
      "id": "repo",
      "title": "PayPal Gimel repository",
      "url": "https://github.com/paypal/gimel"
    },
    {
      "id": "idem",
      "title": "Stripe API idempotency",
      "url": "https://docs.stripe.com/api/idempotent_requests"
    },
    {
      "id": "capture",
      "title": "Adyen Capture",
      "url": "https://docs.adyen.com/online-payments/capture/"
    },
    {
      "id": "fatf",
      "title": "FATF Recommendations",
      "url": "https://www.fatf-gafi.org/en/publications/Fatfrecommendations/Fatf-recommendations.html"
    },
    {
      "id": "pg",
      "title": "PostgreSQL 17 isolation",
      "url": "https://www.postgresql.org/docs/17/transaction-iso.html"
    },
    {
      "id": "kafka",
      "title": "Kafka 4.1 design",
      "url": "https://kafka.apache.org/41/design/design/"
    },
    {
      "id": "cdc",
      "title": "Debezium PostgreSQL 3.3",
      "url": "https://debezium.io/documentation/reference/3.3/connectors/postgresql.html"
    },
    {
      "id": "flink",
      "title": "Flink 1.20 fault tolerance",
      "url": "https://nightlies.apache.org/flink/flink-docs-release-1.20/docs/learn-flink/fault_tolerance/"
    },
    {
      "id": "pci",
      "title": "PCI SSC scope",
      "url": "https://www.pcisecuritystandards.org/standards/pci-dss/"
    }
  ],
  "cases": [
    {
      "candidate": "F01",
      "slug": "stripe-ledger",
      "title": "Stripe Ledger",
      "source": "stripe",
      "published": "2024-02-16"
    },
    {
      "candidate": "F02",
      "slug": "stripe-migration",
      "title": "Stripe Subscriptions migration",
      "source": "migration",
      "published": "2017-02-02"
    },
    {
      "candidate": "F03",
      "slug": "adyen-pal",
      "title": "Adyen Payments Acceptance Layer",
      "source": "adyen",
      "published": "2021-07-28, обновлено 2022-06"
    },
    {
      "candidate": "F04",
      "slug": "wise-activity",
      "title": "Wise Activity Service retry",
      "source": "wise",
      "published": "2021-06-15"
    },
    {
      "candidate": "F05",
      "slug": "monzo-analytics",
      "title": "Monzo событийная аналитика",
      "source": "monzo",
      "published": "2021-10-13 по публикации"
    },
    {
      "candidate": "F06",
      "slug": "nubank-logs",
      "title": "Nubank observability log platform",
      "source": "nu",
      "published": "2025-09-02"
    },
    {
      "candidate": "F07",
      "slug": "paypal-gimel",
      "title": "PayPal Gimel data platform",
      "source": "paypal",
      "published": "2018-04-17"
    }
  ],
  "candidate_scope": "F01–F07 retained from Stage 1.",
  "screened_directions": [
    {
      "company": "Block / Square",
      "url": "https://developer.squareup.com/blog/books-an-immutable-double-entry-accounting-database-service/",
      "status": "RESERVE",
      "scope": "First-party publication on Books, double-entry schema and Spanner, published 2019-10-16."
    },
    {
      "company": "Revolut",
      "url": "https://medium.com/revolut/under-the-hood-engineering-at-revolut-2dc183c04228",
      "status": "SCREENED",
      "scope": "First-party engineering principles article. Insufficient on its own for the requested payment data flow and recovery case."
    }
  ]
}