Pedro Mello — Engineering Field NotesWriting on agent engineering, sovereign infrastructure, software architecture, FinTech and reliable systems.https://pedro.tec.br/Why Every Manifold Sale Must Add Up to Zerohttps://pedro.tec.br/zero-sum-ledger-explained/https://pedro.tec.br/zero-sum-ledger-explained/See how Manifold's zero-sum ledger balances every marketplace sale, rejects missing entries, preserves reversals and keeps currencies auditable.Mon, 24 Aug 2026 00:00:00 GMTBuilding ManifoldManifoldPayments InfrastructureDouble-Entry AccountingMarketplace InfrastructureFinTechSoftware ArchitecturePedro MelloStop Mocking S3: How To Truly do S3 Integration Tests Locally for $0https://pedro.tec.br/stop-mocking-s3-how-to-truly-do-s3-integration-tests-locally-for-0/https://pedro.tec.br/stop-mocking-s3-how-to-truly-do-s3-integration-tests-locally-for-0/Run reliable S3 integration tests locally with MinIO, Docker and the AWS SDK, without cloud credentials, fragile mocks or extra costs.Fri, 08 May 2026 00:00:00 GMTBuilding ManifoldDevOpsHow ToManifoldTutorialAWSS3TestsTutorialsPedro MelloArchitecting a Bulletproof CI Pipeline for a Scalable Next.js Projecthttps://pedro.tec.br/architecting-a-bulletproof-ci-pipeline-for-a-scalable-next-js-projects/https://pedro.tec.br/architecting-a-bulletproof-ci-pipeline-for-a-scalable-next-js-projects/Build a reliable Next.js CI pipeline with ESLint, Prettier, Commitlint and single-command integration tests for a scalable project foundation.Wed, 04 Mar 2026 00:00:00 GMTBuilding ManifoldCIComputer ScienceDevOpsHow ToManifoldStudyPedro MelloFixing Docker DNS Resolution Issues with systemd-resolved on Linuxhttps://pedro.tec.br/fixing-docker-dns-resolution-issues-with-systemd-resolved-on-linux/https://pedro.tec.br/fixing-docker-dns-resolution-issues-with-systemd-resolved-on-linux/Fix Docker DNS resolution failures caused by systemd-resolved on Ubuntu, Debian and other Linux distributions with a safe daemon configuration.Wed, 31 Dec 2025 00:00:00 GMTSoftware EngineeringDevOpsDNSHow ToTutorialPedro MelloHow to Back Up MongoDB on a DigitalOcean Droplethttps://pedro.tec.br/backup-mongodb-digitalocean/https://pedro.tec.br/backup-mongodb-digitalocean/Back up MongoDB on a DigitalOcean Droplet with mongodump, compress the backup and transfer it safely to your local machine over SSH.Mon, 30 Jun 2025 00:00:00 GMTSoftware EngineeringComputer ScienceDevOpsTutorialbackupClouddigitaloceanmongodbmongodumpsshTutorialsPedro MelloStudy on DeFi and Private Credit Liquidityhttps://pedro.tec.br/study-on-defi-and-private-credit-liquidity/https://pedro.tec.br/study-on-defi-and-private-credit-liquidity/Explore DeFi liquidity models, private credit markets, lending protocols and the technical risks involved in connecting on-chain and private assets.Thu, 29 May 2025 00:00:00 GMTFinTech & DeFiDeFiInnovationLending ProtocolsRWAStudyPedro MelloSimple AI Method in 3 minuteshttps://pedro.tec.br/simple-ai-method-in-3-minutes/https://pedro.tec.br/simple-ai-method-in-3-minutes/Learn prediction, classification and linear regression through a concise house-pricing example that introduces a foundational machine-learning method.Wed, 08 Jan 2025 00:00:00 GMTAI & Applied ResearchAIComputer SciencePedro Mello