Pedro Paiva Pedro Paiva (vsppedro) is a software engineer working on email systems and AI agents for email processing and software development, using Ruby on Rails, Python, and AWS SES. https://vsppedro.github.io/feed.xml 2026-11-02T12:15:05-03:00 Pedro Paivahttps://vsppedro.github.io/#about An email lab: experiments for understanding delivery https://vsppedro.github.io/blog/an-email-lab-experiments-for-understanding-delivery/ 2026-10-13T12:00:00-03:00 2026-10-13T12:00:00-03:00 Run five controlled investigations and record what each observation actually establishes. Building reliable email workflows in an application https://vsppedro.github.io/blog/building-reliable-email-workflows/ 2026-10-12T12:00:00-03:00 2026-10-12T12:00:00-03:00 Use durable email intents, explicit send attempts, and authenticated events to recover from failures. Email transport security: what TLS protects https://vsppedro.github.io/blog/email-transport-security-what-tls-protects/ 2026-10-11T12:00:00-03:00 2026-10-11T12:00:00-03:00 Distinguish individual encrypted hops, validated submission, and policies for server-to-server TLS. DMARC: connecting authentication to the visible sender https://vsppedro.github.io/blog/dmarc-connecting-authentication-to-the-visible-sender/ 2026-10-10T12:00:00-03:00 2026-10-10T12:00:00-03:00 Apply the updated DMARC standard to alignment, policies, reports, and a careful rollout. DKIM: how an email carries a verifiable signature https://vsppedro.github.io/blog/dkim-how-email-carries-a-verifiable-signature/ 2026-10-09T12:00:00-03:00 2026-10-09T12:00:00-03:00 Read a DKIM signature, find its public key, and understand what verification proves. SPF: which servers are allowed to send for a domain? https://vsppedro.github.io/blog/spf-which-servers-can-send-for-a-domain/ 2026-10-08T12:00:00-03:00 2026-10-08T12:00:00-03:00 Evaluate SPF identities, mechanisms, forwarding failures, and lookup limits. Accepted, delayed, bounced: understanding email delivery outcomes https://vsppedro.github.io/blog/accepted-delayed-bounced-email-delivery-outcomes/ 2026-10-07T12:00:00-03:00 2026-10-07T12:00:00-03:00 Use delivery timelines and status codes to distinguish acceptance, retry, and permanent failure. Inside an email: MIME, HTML, attachments, and encoding https://vsppedro.github.io/blog/inside-an-email-mime-html-attachments-and-encoding/ 2026-10-06T12:00:00-03:00 2026-10-06T12:00:00-03:00 Inspect MIME alternatives, attachments, inline images, and encodings in a saved message. How DNS tells email servers where to deliver a message https://vsppedro.github.io/blog/how-dns-routes-email/ 2026-10-05T12:00:00-03:00 2026-10-05T12:00:00-03:00 Read MX preferences, address lookups, null MX, and DNS failures without guessing mailbox validity. Email envelopes and headers: why there is more than one sender https://vsppedro.github.io/blog/email-envelopes-and-headers/ 2026-10-04T12:00:00-03:00 2026-10-04T12:00:00-03:00 Separate the displayed sender, reply destination, and delivery-failure address. An SMTP conversation, step by step https://vsppedro.github.io/blog/an-smtp-conversation-step-by-step/ 2026-10-03T12:00:00-03:00 2026-10-11T15:41:40-03:00 Follow a welcome email through the conversation between mail servers, from the first greeting to final acceptance. How email works: the components behind a message https://vsppedro.github.io/blog/how-email-works-the-components-behind-a-message/ 2026-10-02T12:00:00-03:00 2026-10-11T09:16:17-03:00 Meet the clients, servers, and mailboxes behind a welcome email. What happens after my application sends an email through AWS SES? https://vsppedro.github.io/blog/what-happens-after-my-application-sends-an-email-through-aws-ses/ 2026-10-01T12:00:00-03:00 2026-10-10T19:47:28-03:00 Follow a welcome email through SES, from the first API response to the receiving server and the delivery events our application needs.