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Featured in Domain Arrivals · 2026-08-19

Robin: An SMTP Client That Can Misbehave on Purpose

robinmta.com ↗ · Developer Corner · score 86.0
Open: public page gives enough substance to understand the site $Paid: pricing, booking, ecommerce, subscription, or paid access is visible ADAds: visible ad load or ad-supported content Pretty: notable design, copy, craft, or presentation Pro: polished, finished-feeling, serious, or operationally mature Niche: specific audience, workflow, or unusually focused use case Human: personal, local, community, civic, handmade, or real-person signal !Suspicious: scammy, spammy, trust theater, finance fog, or credibility concern

Robin is an open-source Java suite combining a socket-level SMTP client, a deliberately breakable MTA, and a JSON test engine for inspecting entire email pipelines.

Why it surfaced

The client can force TLS versions, split BDAT frames across TCP writes, delay individual writes, cut connections mid-message, and replay awkward AUTH behavior. Alongside it, the breakable server injects controlled failures while the tester checks logs, IMAP, APIs, and MIME—not just SMTP status codes.

The Song Resumes After the Story

August 19’s newborn domains include a Hawaiʻi road-trip radio that resumes each song after a GPS-triggered story, an offline Chattanooga recovery map, a 100 KiB operating system running Doom, and an archive of 169,588 Discord roleplay messages.

This is one of 1,000 discoveries in the 2026-08-19 Domain Arrivals issue.