Seven million emails from a single binary peaking at 57 MB of RAM: listmonk is a high-performance newsletter and mailing list manager in Go with PostgreSQL as its only dependency - no Redis, no worker processes, no message broker. The project's own production benchmark sent 7+ million emails with the binary peaking around 57 MB of RAM, and throughput exceeds 100K emails per hour on modest hardware. Campaigns run through a multi-threaded, multi-SMTP queue with round-robin delivery, per-server concurrency, retries, and sliding-window rate limiting across providers like Amazon SES, SendGrid, Mailgun, or your own Postfix relay. Subscribers carry custom JSON attributes and are segmented with raw SQL queries, so any audience Postgres can express, listmonk can target. Templates use Go template syntax with 100+ functions for dynamic per-subscriber content, and the Vue dashboard reports opens, clicks, bounces, and unsubscribes with automated bounce processing. A REST API handles transactional email and programmatic control, a built-in media library hosts campaign assets, and CSV or API import migrates lists from hosted platforms. The economics are the headline: where Mailchimp pricing scales with list size, listmonk plus Amazon SES sends the same volume for hosting cost plus roughly $0.10 per thousand emails - commonly a 95% reduction - and your email list, a core business asset, stays on your own infrastructure. AGPLv3-licensed; bring your own SMTP provider for delivery.

Marketing campaigns and transactional mail from one open-source platform: Notifuse is a modern, self-hosted alternative to Mailchimp, Brevo, and Klaviyo without per-email or per-contact pricing. Built with Go and React on PostgreSQL, it separates concerns cleanly: a drag-and-drop visual builder composes responsive templates from MJML components with Liquid variables like {{ contact.first_name }} and per-template version history; campaigns add A/B testing across subject lines, content, and send times; and a REST transactional API serves application-triggered mail. Delivery routes through your choice of provider - Amazon SES, Mailgun, Postmark, SendGrid, SparkPost, Mailjet, or plain SMTP - with multi-provider failover. Contacts carry custom fields and a full activity timeline (messages, profile changes, webhook events), and real-time segmentation builds dynamic rules over properties, activity, and subscriptions. Event-driven automations create behavioral sequences, a notification center gives recipients self-service preference management, and an S3-compatible file manager handles images with CDN delivery. Multi-tenant workspaces with isolated databases and custom domains suit agencies. Open and click tracking report engagement in real time.

One statically-compiled Go binary over PostgreSQL, no ORM, no framework, static assets embedded in the executable: Miniflux is the minimalist, opinionated feed reader. The opinions are the feature: page layout, fonts, and colors are tuned for reading, and everything else is treated as noise. It consumes Atom, RSS, and JSON Feed formats with OPML import/export, organizes articles with categories and bookmarks, fetches original full-text content for summary-only feeds, and provides Postgres-powered full-text search. Privacy work happens automatically: pixel trackers are stripped, tracking parameters removed from URLs, a media proxy blocks third-party tracking, referrers are never forwarded, and there is zero telemetry. Navigation is keyboard-first - j/k through items, o to open, f to star - with touch gestures on mobile. Podcast, video, and music enclosures are supported, and YouTube videos play inline. Over 25 integrations save articles onward to Wallabag, Readwise Reader, Pinboard, Linkding, Instapaper, Notion, Telegram, Matrix, Ntfy, and more, plus webhooks and a REST API with Go and Python clients; the Google Reader API endpoint supports existing mobile reader apps. Authentication spans local passwords, passkeys (WebAuthn), Google OAuth2, OpenID Connect, and reverse-proxy headers. It is Apache 2.0 licensed, translated into 20 languages, and updates feeds on an internal scheduler.

Among open-source Mailchimp alternatives, Keila has the most modern UI - built in Germany on Elixir and Phoenix (the PETAL stack), with GDPR-conscious defaults including an optional no-tracking mode, and 100% open source with no proprietary premium tier. Campaign authoring is flexible three ways: a visual block editor with multi-column layouts, Markdown with or without WYSIWYG for hybrid HTML-plus-plain- text sends, and raw MJML for hand-coded designs. The personalization system is unusually clean - every contact carries custom data as a single JSON object (populated from sign-up form fields or pushed from your CMS/CRM), and Shopify's Liquid template language renders it into fully dynamic emails. Targeting uses a visual segment editor backed by a powerful segment language for complex logic over tags, language preferences, and any custom field. Sign-up forms with custom fields grow your lists; open and click tracking measures campaigns; scheduled sending handles timing. Delivery pipes through your own SMTP or first-class integrations with AWS SES (including automated bounce handling), SendGrid, Mailgun, and Postmark. A full REST API manages contacts, campaigns, and segments, with Erlang/OTP reliability underneath. Comfortable at 100K+ subscribers. AGPL-licensed, EU-hosted project, actively developed.

Where Miniflux strips reading down, FreshRSS gives you knobs - the feature-rich pole of self-hosted RSS, comfortable with thousands of feeds. It's a multi-user PHP aggregator (host family and friends on one instance, with an anonymous reading mode) with the reading workflow refined over a decade: favorites, custom tags, powerful filter and search queries, three reading views, and statistics that reveal each site's publishing frequency - useful for pruning subscriptions. Two properties make it the standard choice. First, the Google Reader-compatible API (plus a Fever API) syncs with virtually every serious RSS client - Reeder, NetNewsWire, ReadYou, FeedMe, Fluent Reader - so your phone reads from your server. Second, native WebSub support means compatible sources (WordPress, Blogger, Medium, Friendica) push new articles instantly instead of waiting for polling. A 50+ extension ecosystem adds what truncated feeds omit - full-text content fetching, reading-time estimates, trending views, auto-unsubscribe for dead feeds - alongside community themes and custom CSS. OPML import/export keeps subscriptions portable, a CLI handles administration, and article sharing posts to many services. AGPL-licensed, running on SQLite, MySQL, or PostgreSQL. Feedly Pro's feature set, minus Feedly's subscription and its algorithms.

The antidote to doomscrolling: Upvote RSS turns Reddit, Hacker News, Lemmy, Lobsters, PieFed, Mbin, and trending GitHub repositories into calm, filtered RSS feeds. The MIT-licensed PHP app's killer feature is intelligent filtering: beyond simple score thresholds, the "posts per day" filter analyzes a community's recent history and computes the score cutoff that yields your target volume - say, exactly three r/technology posts daily - while a percentage-based threshold mode stays consistent as communities grow. Feeds are rich, not bare links: parsed full-article content via Readability (with optional Readability.js, Mercury, or Browserless for JavaScript-heavy pages), embedded videos and image galleries, top-voted comments with pinned-moderator filtering, scores, reading-time estimates, and optional AI summaries through Ollama, OpenAI, Gemini, Anthropic, Mistral, DeepSeek, or any OpenAI-compatible endpoint - with automatic provider fallback. A web UI builds the feed URL interactively with live preview; paste the result into any RSS reader. Reddit support includes custom domains like old.reddit.com plus NSFW filtering and blurring. Caching via filesystem, Redis, or APCu keeps repeated fetches cheap and avoids re-running paid summarizations.