Peter Ullrich's Picture

Hey, I’m Peter! Developer & Educator.

I'm an Elixir developer with a Psychology background, Founder of Letter to Yourself, Ex-YouTuber at PeterAndCode, Ex-Host of ExplainBlockchain, and ConsenSys-certified Blockchain developer. Passionate about sharing knowledge, sports, Africa, and bicycle activism.

an old wizard listening through a door, digital art

Listen to Database Changes with Postgres Triggers and Elixir

Postgres Notifications allow you to subscribe to any changes in your database, even if they weren't made by your Elixir application! Let's learn how to set them up!

– 11 min read
postgres elixir
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Build dynamic Forms with JSON Schemas

Define custom forms without writing a single line of HTML. JSON Schemas help you define and adjust forms and validate user input all through a single configuration file.

– 13 min read
elixir liveview
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Use Neural Networks in Livebook

The latest Livebook version 0.8 comes with a new smart cell type that makes experimenting with neural networks like StableDiffusion, GPT2, and others incredibly easy. Let's learn how to get started.

– 7 min read
livebook elixir-nx
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Build a Roles and Permissions System for Phoenix - Part 2

Learn how to prevent PII leaks from your Ecto queries by adding query restrictions to your Roles and Permissions system.

– 18 min read
rap elixir
A phoenix rising from a computer screen

Build a Roles and Permissions System for Phoenix - Part 1

Learn how to control access to your system by assigning granular roles and permissions to your users.

– 18 min read
rap elixir
A developer holding a mug of coffee with shaky hands staring at a computer

Simulate Latency, Jitter, and Package Loss in Phoenix LiveView

Learn how to make your LiveView app more resilient by simulating bad internet connections.

– 6 min read
liveview elixir
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The Complete Guide to Full-text Search with Postgres and Ecto

A detailed deep-dive into efficient full-text search for multiple languages, result ranking, tsvectors and tsqueries, search modifiers, and so much more.

– 28 min read
ecto elixir
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Efficient Name Search with Postgres and Ecto

Search through millions of strings efficiently using indexed ILIKE or SIMILARITY queries.

– 19 min read
ecto elixir
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Prevent overlapping time ranges with Ecto and Postgres

Block overlapping appointments efficiently in your database using exclusion constraints and don't worry about double-bookings ever again!

– 12 min read
ecto elixir
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Optimize Ecto's insert_all with Placeholders

Write more efficient bulk insert queries and avoid sending duplicate data by using placeholders.

– 6 min read
ecto elixir