Elixir Mentor

Mark Cotner is a DBA managing around a thousand databases by day and a telecom CTO by night — building hospitality cable networks for RV parks, nursing homes, and apartment complexes at 100% annual growth. In this episode, he walks through the infrastructure, the business, and the two-year project that just landed on Hex: Timeless, an embedded observability suite for Elixir built on Rust NIFs, hitting 3 million metric inserts per second with 14:1 compression.We get into what a hospitality network actually looks like — branded cable hardware, DOCSIS provisioning, and mesh Wi-Fi across dispersed sites — and how Mark's team handles monitoring across thousands of cable modems using a full Elixir stack (DHCP, TFTP, NTP, and Ash). He also shares how a frustrating Ansible setup led him to build something he thought should exist: a lightweight, embeddable observability backend that drops into a Phoenix app in under five minutes via Igniter, with less than 5% CPU overhead.The technical core of the conversation covers the Timeless architecture in depth — PCO compression for metrics, OpenZL for logs and traces, 15 rounds of iteration before landing on a single consolidated Rust NIF, and why the Elixir-to-Rust translation layer ended up being the real bottleneck. Mark also talks benchmarking against Victoria Metrics on a 192-core AWS ARM instance, the custom C web server (Rocket) he built to cut HTTP latency 30x below Bandit, and how supervision trees let him pack an entire DOCSIS provisioning stack into one Elixir app without worrying about cascading failures.Whether you're curious about Elixir in telecom, Rust NIF development, time series database internals, or just want to hear what 30 years of observability experience looks like applied to the BEAM, this one is packed.Resources Mentioned:- Timeless on Hex: https://hex.pm/packages/timeless_phoenixConnect with Mark:- X/Twitter: https://x.com/awksedgreepSUPPORT ELIXIR MENTOR- Elixir Mentor: https://elixirmentor.comSponsored by BEAMOps — scalable Elixir deployments and infrastructure migrations, authors of Engineering Elixir Applications: https://beamops.co.ukElixir AI Collective Discord — your community for coding Elixir with AI: https://agentjido.xyz/discord

George Millo, creator of Learn Phoenix Live View and Gauntlet AI alumnus, is an Elixir educator and engineer focused on AI-first workflows. He discusses agentic coding realities like verification debt, planning before prompting, and working in small self-contained PRs. He explores Elixir and the BEAM as natural fits for agent architectures and warns about security risks when giving AI tools codebase access.

Leandro Pereira is back on the Elixir Mentor Podcast — this time to dive deep into MDEx, his Rust-powered Markdown library for Elixir. MDEx is built on the Comrak Rust crate, runs 31x faster, and uses 3,500x less memory than existing Elixir alternatives. We also get into Lumis, his standalone syntax highlighting engine powered by tree-sitter and Neovim themes.Leandro walks through why he chose a Rust NIF over a pure Elixir implementation, what it took to ship Lumis as its own project, and the surprisingly hard technical challenge at the heart of MDEx: streaming Markdown for AI applications. We discuss how MDEx handles incomplete Markdown fragments in real time, what the upcoming Components feature unlocks for Phoenix/LiveView developers, and how the HEEx parser integration works under the hood.We also cover the human side of maintaining two solo open source projects: how Leandro prioritizes, uses AI to chip away at the backlog, and thinks about monetization. The conversation goes deeper into how the AI era has changed Markdown's role in the ecosystem, the pitfalls of vibe coding, and what it really takes to get an open source project noticed — including the uncomfortable truth that marketing matters more than most developers want to admit.The episode closes with a wide-ranging conversation on developer growth — the Dunning-Krueger curve, making the mental shift from OOP to functional programming, and why Elixir feels easier once it finally clicks. A great listen for anyone building libraries, wrestling with Rust NIFs, or navigating open source in the Elixir ecosystem.Resources Mentioned:- MDEx: https://mdelixir.dev- MDEx on Hex: https://hex.pm/packages/mdex- Lumis: https://lumis.sh- Lumis on Hex: https://hex.pm/packages/lumisConnect with Leandro:- X/Twitter: https://x.com/leandrocesquini- GitHub: https://github.com/leandrocp/mdexSPONSORS- Paraxial.io: https://paraxial.io- Jido (Elixir AI Collective Discord): https://agentjido.xyz/discordSUPPORT ELIXIR MENTOR- Elixir Mentor: https://elixirmentor.com

Josh Price, founder & CTO of Alembic and one of the core forces behind Ash Framework, joins me for a wide-ranging conversation that starts with the origin story of Alembic, winds through the history of GraphQL and Ash, and lands on Clarity — his new interactive introspection and visualization tool for understanding your Ash codebase. Josh has been writing Elixir for over ten years and building Alembic for nine, which gives him a rare perspective on how the ecosystem has matured and where it's headed in an agentic world.We trace how Josh's frustration with real-time data at a gaming company pointed him toward Elixir and Erlang, how that led to an obsession with GraphQL domain modeling, and how that obsession eventually collided with Ash — which turned out to solve exactly the problems he'd been hacking around for years. We talk about what Ash actually is beyond an API generator, why auto-generated migrations are criminally underrated, and why the developers who resist Ash most are often the ones in the middle of the experience curve. Josh also shares the inside story of how slowing Zack Daniel down was actually the best thing that ever happened to the Ash ecosystem.A big chunk of the conversation covers the AI moment we're in right now — Claude Code workflow tips (including the /insights command and how to keep session history beyond 30 days), why CLIs are beating MCPs for LLM tool use, Claude Code skills and usage rules for progressive disclosure, and how Clarity grew from Ash's built-in introspection into something far more interesting: an in-memory Erlang digraph knowledge graph of your entire Elixir application. Josh also shares his take on multi-model databases, the disappearance of the UI, and why the only limits left for software engineers are taste, judgment, and imagination.Resources mentioned in this episode:- Alembic: https://alembic.com.au- Clarity (Hex): https://hex.pm/packages/clarity- Ash Framework: https://ash-hq.org- Ash Framework book: https://pragprog.com/titles/ldash/ash-framework/- Killswitch: https://killswitch.appConnect with Josh:- Website: https://alembic.com.au- X/Twitter: https://x.com/joshprice- LinkedIn: https://www.linkedin.com/in/joshcpriceSponsors:- Paraxial.io: https://paraxial.io- Jido: https://agentjido.xyz/discordSUPPORT ELIXIR MENTOR- Elixir Mentor: https://elixirmentor.com

Thomas Athanas, Head of Engineering at LevelAll, is an infrastructure-focused leader who builds systems to avoid vendor lock-in. He talks about moving off PaaS to bare metal, handling 50,000 concurrent education users, removing LiveView and Ash from production, using AI as a “Lore Master” for institutional memory, and migrating auth from Auth0 to FusionAuth after rate-limit failures.

Amos King, Senior Staff Backend Engineer and founder of Binary Noggin, mixes systems engineering roots with decades in Erlang/Elixir. He discusses mentorship and why teaching helps the teacher. They cover team composition and diverse backgrounds, the shift from OO to functional thinking, when not to overuse GenServers, meetup value, and a surprising real-world query optimization story.

In this episode of the Elixir Mentor Podcast, I chat with Dave Lucia, CTO and Co-Founder of TV Labs. Dave returns to the podcast to talk about building an AI-powered smart TV testing platform that lets media companies test streaming apps on hundreds of real physical devices through the cloud — all built primarily in Elixir.Dave walks through the founding of TV Labs, from meeting his co-founder at Bloomberg over a decade ago to building an MVP with WebRTC during the pandemic. He covers the technical challenges of managing a massive device lab — procurement, warm-up processes, security isolation, session management, and keeping hundreds of TVs, Rokus, Fire TVs, and Apple TVs healthy and available for enterprise clients. The platform uses a custom KQL query engine for real-time device matching and a licensing system built on Elixir GenServers sharded across the cluster.We get into Dave's 10-year history with Elixir in production, starting at Bloomberg and carrying through to TV Labs. He explains why Elixir was the right fit for orchestrating physical devices at scale, from its standard library minimizing dependencies to building Apple device communication libraries and even a Lua 5.3 interpreter directly in Elixir. Dave also shares how TV Labs uses OpenTelemetry for observability and runs multi-region infrastructure with session recording capabilities.The conversation shifts to AI, where Dave describes using Claude and other LLMs to accelerate development, automate operations like vendor management and support emails, and build AI agents for QA testing. We wrap up with a candid discussion on whether AI will replace developers and how these tools are fundamentally changing what's possible for small teams.Connect with Dave:- Website: https://davelucia.com- X/Twitter: https://x.com/davydog187- LinkedIn: https://www.linkedin.com/in/david-lucia-a395441b/Sponsors:- BEAMOps: https://beamops.co.uk- Paraxial.io: https://paraxial.io- Jido: https://agentjido.xyz/discordSUPPORT ELIXIR MENTOR- Elixir Mentor: https://elixirmentor.com

Rob Walling, serial entrepreneur and author who bootstrapped Drip and co-founded TinySeed and MicroConf. He explains starting with small wins, stacking micro-products, and the stair-step approach to SaaS. He talks about why developers avoid marketing, when to learn selling versus hire, pitfalls of two-sided marketplaces, and how AI will reshape niche SaaS without ending winners.

Jamil Bou Kheir, founder of Firezone and ex-Cisco security engineer, built a YC-backed open-source zero-trust access platform using Elixir and Rust. He recounts Firezone’s start as a WireGuard UI, the split control-plane (Elixir) and data-plane (Rust), and SnowNet for NAT traversal. Conversation also covers scaling, Postgres WAL streaming, observability, large refactors, and open-source licensing choices.

In this episode of the Elixir Mentor Podcast, I chat with Enrique Leigh, founder of Prende Café in Chile. We explore how he built a specialty coffee subscription business using Phoenix LiveView, his journey from marketing and ad tech to becoming an Elixir developer, and why he chose custom e-commerce over platforms like Shopify.Enrique shares the WordPress crash during a Chile vs Brazil match that sparked his interest in Elixir, and how building his own coffee business became the perfect way to finally learn the language. We discuss UX principles from "Don't Make Me Think," marketing frameworks like Jobs to Be Done, and the counterintuitive lesson that adding more checkout steps can actually increase conversions. He also explains the specialty coffee value chain, from sourcing beans in Brazil to roasting and running a physical café alongside the e-commerce platform.Our conversation covers practical entrepreneurship topics including MVP philosophy, building subscription and coupon systems with Mercado Pago, using Oban for job scheduling, and content marketing strategies that work. Enrique shares insights on balancing Iron Man training with running a family business, productivity techniques from the Flow Research Collective, and the evolving landscape of ad tech after GDPR. We also discuss his future goals of learning Nerves to build IoT coffee machines and the growing Elixir community in Chile.The episode wraps up with advice for aspiring entrepreneurs: just launch it. Enrique emphasizes that the cost of inaction is often greater than the cost of action, and with tools like LLMs that work remarkably well with Elixir, there's never been a better time to build your own products.Resources Mentioned:- Don't Make Me Think: https://sensible.com/dont-make-me-think/- Oban: https://getoban.pro/- Jido: https://agentjido.xyz/discordConnect with Enrique:- Website: https://www.prendecafe.cl- X/Twitter: https://x.com/EnriqueLeigh- LinkedIn: https://www.linkedin.com/in/enriqueleigh/Sponsors:- Paraxial.io: https://paraxial.io- Jido: https://agentjido.xyz/discordSUPPORT ELIXIR MENTOR- Elixir Mentor: https://elixirmentor.com