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Tomas Reyes

Test automation architect, financial platforms

Pen name. The company does not publish engineers' real names.

Builds regression suites and test data pipelines for ledgers, APIs, and webhooks. Writes about frameworks, environments, and synthetic financial data.

  • Tooling

    k6 load testing tutorial: authorisation and capture under load with k6 v2.3.0

    A k6 v2.3.0 load test for a payment application programming interface (API) drives authorisations at a controlled arrival rate with the ramping-arrival-rate executor, gives each virtual user iteration its own idempotency key, and fails the run on 95th and 99th percentile latency per operation, error rate, check rate, and dropped iterations.

  • Tooling

    Testcontainers Kafka tests for a payment event pipeline: redelivery and ledger state

    Testcontainers with Kafka lets an integration test start a real Kafka broker, here confluentinc/cp-kafka:8.3.2 through @testcontainers/kafka 12.1.0 for Node.js, next to a Postgres ledger. The test for a payment event pipeline stops the consumer after the database commit and before the offset commit, then asserts one set of ledger postings per event after Kafka redelivers.

  • Tooling

    Pact contract testing for a checkout service and a payments API (pact-js 17.1.4)

    Pact contract testing lets a checkout service record the payments application programming interface (API) responses it depends on and makes the payments API verify them before release. With pact-js 17.1.4, match money amounts with the integer matcher: in our run on 2026-09-22, the type matcher accepted a provider response of 100.5 where the contract expected 10050 minor units.

  • Tooling

    WireMock tutorial: stubbing a payment processor with WireMock 3.13.2

    This WireMock tutorial stubs a payment processor with WireMock 3.13.2 JSON (JavaScript Object Notation) mappings: an approval, a soft decline, a timeout after approval using fixedDelayMilliseconds, an authorise-then-capture state machine built from scenarios, and a capture webhook. Every mapping was re-run against WireMock 3.13.2 on 22 September 2026 with synthetic tokens.

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