Introduction | Layers Documentation

Presentation layer

In the seven-layer OSI model of computer networking, the presentation layer is layer 6 and serves as the data translator for the network.[2][3][4] It is sometimes called the syntax layer.[5]

ATProto Architecture

Visual summary of the AT Protocol architecture: PDS, AppView, identity, records, lexicons.

An introduction to "introduction": a common but rarely-named systems concept

Introduction is not always just a simple map from a name to a response containing addresses. In fact, it's more interesting when it's not simple.

The 2026-07-28 Specification

The 2026-07-28 Model Context Protocol specification is out, bringing a stateless protocol core, Multi Round-Trip Requests, header-based routing, cacheable list results, authorization hardening, a formal extensions framework, and updated Tier 1 SDKs.

The Web Needs a Context Layer Built on a Shared Protocol

Making context a shared protocol, rather than a platform feature, would let readers see competing perspectives anywhere on the web, argue Mallory Knodel, Evan Friedman, and Brad Friedman.

The Story Behind our Brand Illustration

Our brand illustration shows three layers: the foundation being built, the valley we're stuck in, and the world waiting above. Here's what it all means.

When and how to use the section element

So what on earth is a <section> element actually for? The answer isn’t as obvious as you might have hoped, but it’s definitely straightforward.

ATmentions

Webmentions for the ATmosphere — a tiny open-source widget that shows how the atproto network reacted to any page, with no accounts and no lock-in.

Layers

Composable lexicons for linguistic annotation on ATProto

Deep dive into iroh: A replacement for WireGuard or a P2P layer for your application?

Just last week, the iroh project announced the release of its v1.0. What is iroh? Well, I&#39;m glad you&#39;re asking because it&#39;s a very interesting project that I&#39;m following for

at3d.app docs — lexicon reference

Every record type in the app.at3d namespace. These AT Protocol Lexicons define portable 3D identity data stored in a user's Personal Data Server.

Reticulum Network

For the better part of a generation, we have been taught to visualize the digital world through the lens of hierarchy. The mental maps we carry are dominated by a single, misleading image: The Cloud.

CIDs: What You Need to Know and Why, Part 1 - Nick's Blog

A deep dive into Content Identifiers, the self-describing cryptographic fingerprints that form the foundation of ATProtocol’s data model.