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 throwing a big key into the cloudy sky, digital art

Upload Encrypted Files to S3

Encrypting sensitive user files before uploading them to S3 is a must. This post shows how to encrypt and upload them and also how to download and decrypt them again using encryption keys unique per user.

– 24 min read
liveview s3 encryption aws
an old wizard holding up a VCR videocassette into the camera standing in his chemical laboratory, digital art

Announcing my new Video Course!

My first video course "Build an MVP with Elixir" helps you to get started with Elixir by building a real-world product together!

– 1 min read
postgres liveview elixir
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
an old map with marked countries and their flags lying on a wooden table, old wizard hunching over the map, digital art

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
A futuristic numbat reading a book

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
A phoenix rising from a computer screen

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
A librarian frantically searching through a catalog of books

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
A librarian searching through a thick book

Efficient Name Search with Postgres and Ecto

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

– 19 min read
ecto elixir