Elixir Mentor

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/lumis
Connect with Leandro:
- X/Twitter: https://x.com/leandrocesquini
- GitHub: https://github.com/leandrocp/mdex
SPONSORS
- Paraxial.io: https://paraxial.io
- Jido (Elixir AI Collective Discord): https://agentjido.xyz/discord
SUPPORT 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.app
Connect with Josh:
- Website: https://alembic.com.au
- X/Twitter: https://x.com/joshprice
- LinkedIn: https://www.linkedin.com/in/joshcprice
Sponsors:
- Paraxial.io: https://paraxial.io
- Jido: https://agentjido.xyz/discord
SUPPORT ELIXIR MENTOR
- Elixir Mentor: https://elixirmentor.com

Thomas Athanas, Head of Engineering at LevelAll, joins me on the Elixir Mentor Podcast to talk through the infrastructure, architectural, and leadership decisions that come with building systems you actually own — and what happens when vendor lock-in catches up with you in production.
Thomas walks through LevelAll's move away from Fly and Gigalixir toward bare metal hardware, the thundering herd problem that comes with serving 50,000 concurrent education users, and why they made the call to remove both Phoenix LiveView and Ash framework from production. We get into Ash APS premium support, JSONB query challenges, and the tradeoffs of leaning on a framework when hiring for it is hard.
We talk about using AI as a development planning tool and context keeper for managers — including Thomas's "Lore Master" concept, where AI agents preserve institutional knowledge so it never walks out the door. From there we get into the Auth0 rate limiting incident that hit during a live onboarding, the FusionAuth migration that followed, enterprise auth requirements like OIDC and SAML, and the bcrypt hash conversion work that made it all possible. Thomas also shares his work on a custom Erlang-based bare metal deployment agent and his approach to Postgres configuration and backups with pgBackRest.
The second half covers founder mode mentality, total ownership of problems, the player-coach leadership style, Sanity CMS vendor lock-in, building an audience vs. building a customer base, and practical advice for technical founders who keep procrastinating with features instead of making sales.
Connect with Thomas:
- X/Twitter: https://x.com/ThomasAthanas
- LinkedIn: https://www.linkedin.com/in/thomasathanas/
Sponsors:
- BEAMOps: https://beamops.co.uk
- Paraxial.io: https://paraxial.io
- Jido: https://agentjido.xyz/discord
SUPPORT ELIXIR MENTOR
- Elixir Mentor: https://elixirmentor.com/?utm_source=elixir-mentor

In this episode of the Elixir Mentor Podcast, I sit down with Amos King, Senior Staff Backend Engineer at Adobe, founder of Binary Noggin, and longtime Elixir community contributor. We dig into mentorship, knowledge sharing, and the team dynamics that make software organizations actually thrive.
Amos traces his non-traditional path into software — from structural engineering to manufacturing automation to Erlang on Navy submarines — and explains how that background shapes how he thinks about building reliable systems. We talk about his decade running Binary Noggin, why he ultimately made the move to Adobe, and the hard lessons learned when the consulting market shifted. From there the conversation goes deep on team composition, why diverse backgrounds matter more than uniform credentials, and the mindset shift from object-oriented to functional programming.
We also get into the practical side of Elixir: when GenServers are the right tool and when they're not, why vibe coding worries him from an engineering quality standpoint, and why teaching is actually a selfish act that benefits the teacher most. We close out with what separates a real staff engineer from a senior one, a call for the Elixir community to revive local meetups, and a real-world database query optimization story that reframes how to think about performance problems.
Resources Mentioned:
- Binary Noggin: https://binarynoggin.com
Connect with Amos:
- X/Twitter: https://x.com/Adkron
- LinkedIn: https://www.linkedin.com/in/amosking/
SPONSORS
- BEAMOps: https://beamops.co.uk
- Paraxial.io: https://paraxial.io
- Jido: https://agentjido.xyz/discord
SUPPORT ELIXIR MENTOR
- Elixir Mentor: https://elixirmentor.com

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/discord
SUPPORT ELIXIR MENTOR
- Elixir Mentor: https://elixirmentor.com