Hast Code Innovation
HastCode explains how real systems are built for mid-to-senior backend engineers, focusing on the architecture, design choices, and operational costs behind the software they use and run.
Latest stories
- How Cloudflare D1 runs millions of SQLite databases
How Cloudflare D1 keeps its central Postgres off the query path of millions of SQLite databases, at the price of limits that act seconds late.
- Structured concurrency: why child tasks never outlive their parent
Structured concurrency ties concurrent tasks to the block that starts them, so none outlives its parent and errors and cancellation follow the tree.
- GitHub's Dependabot backlog: a queue flooded by its own fan-out
On 23 October a fan-out of Dependabot alert events flooded a shared queue and delayed push events. GitHub isolated it and throttled it.
- Connection reuse in HTTP/1.1, HTTP/2 and HTTP/3: how each works and where each breaks
How HTTP/1.1, HTTP/2 and HTTP/3 reuse connections, where each one breaks, and which to use for calls between services.
- Single-tenant Titus: how Netflix gives one container its own VM
How Netflix's Titus gives a few noisy or sensitive workloads a dedicated, right-sized EC2 instance under the same container API, and what that costs.
- Metastable failures: why systems stay down after the trigger is gone
A metastable failure outlives its trigger because a loop such as retries keeps the system overloaded. How the loop works and what breaks it.
- Briefs | HastCode
On 23 October a fan-out of Dependabot alert events flooded a shared queue and delayed push events. GitHub isolated it and throttled it.
- FrankenPHP: a PHP application server with the interpreter inside Caddy
FrankenPHP embeds the PHP interpreter in the Caddy web server: one Go binary, a worker mode, no PHP-FPM, but every extension must be thread-safe.
- OpenShell: NVIDIA's sandboxed runtime for autonomous AI agents
OpenShell is NVIDIA's self-hosted sandbox runtime for AI agents: kernel-enforced policy and a credential proxy, at the cost of a fast-moving 0.1 API.
- witr: a CLI that traces a process, port or container to what started it
witr is a single-binary CLI and TUI that traces a process, port, container or file to what started it: a point-in-time diagnostic, not a monitor.
- etcd: a Raft-replicated key-value store for coordination data
etcd is a Raft-replicated, linearizable key-value store for coordination-sized data; fast disks and a few-gigabyte ceiling are the price.
- Apache Iggy: a persistent message stream in Rust
Apache Iggy is a Kafka-shaped message streaming log in one Rust binary, built for tail latency; pre-1.0, so upgrades need a fresh data directory.

