Plaza

A fast, local-first Nostr client, built natively in Zig.

Plaza is the flagship app of the zig-nostr ecosystem, a native Nostr client where you read without an account and post in four clicks, and the feed renders from disk. It's built on the nostr protocol library, and can sign through Notary so your key never enters a client.

Status: early. A first run opens straight into a feed, signed in as nobody: a curated starter pack, already populated, with a strip along the top offering a key when you want one. Create an identity, bring an existing key, or connect an external signer (Notary) over NIP-46 so your key never touches the app. The feed carries real names, avatars and pictures, rendered straight from a local store that a pool of background threads keeps filled, one process, no IPC. Composing signs a note (locally, or by a round-trip to the signer) that is stored at once and published to the pool. Private messages land in a milestone ahead. macOS first.

What it looks like

_{Real windows, photographed from the running app against real notes from public relays. Every pixel inside the window is the app's own, so nothing here shows a screen the app cannot draw.}

Install

curl -fsSL https://raw.githubusercontent.com/zig-nostr/plaza/main/scripts/install-macos.sh | bash

macOS on Apple Silicon. The installer verifies the download's SHA-256, installs Plaza.app, clears the download-quarantine flag so it opens without a Gatekeeper detour, and launches it. It touches the bundle and nothing else: your key, session and local store live in ~/.plaza and survive every upgrade.

Plaza is ad-hoc signed and not notarized on purpose. It signs notes with your key, so the trust anchor is a build you can reproduce rather than an Apple signature you cannot inspect. Read the installer, or build the same artifact yourself:

scripts/package-macos.sh   # -> dist/Plaza.app, ad-hoc signed

Performance

The feed is a windowed list: it builds only the rows near the viewport, so what it costs follows the window rather than the length of the feed. Measured on the build that ships (ReleaseFast), scrolling hard through a live feed on an account that follows three hundred people:

Stage	p90	Budget
Rebuild	315us	700us
Layout	1700us	2400us
Patch	57us	200us

A 120 Hz frame is 8333us, so a hard scroll spends about a quarter of one, and the GPU path never falls back to CPU pixels. A long feed mounts around 330 widget nodes rather than one per note.

The number that matters is that it does not move with the size of the account. The same scroll on the same machine, before the feed stopped asking the database who you follow once per card, cost 24423us per rebuild: three whole frames to draw one, and worse the more people you followed.

The feed reads every account you follow, not a slice of it. At the ceiling of 2048, with each of those accounts carrying a profile older than their notes (which is the real shape: a bio is written once and posted over ever since), a rebuild measures 5989us against the 16667us of a 60Hz frame. The subscription splits those authors across filters relays will accept and sends them in one REQ, so it asks about all of them rather than the first few hundred.

That ceiling is measured by the test suite rather than by the script below:

zig build test -Doptimize=ReleaseFast

Measure it yourself, and fail on a regression:

scripts/frame-budget.sh

Develop

native dev     # build and run with hot reload
native test    # run the test suite
native build   # produce a ReleaseFast binary in zig-out/bin/
native check   # validate the markup and manifest

Before a release there is a second suite, which drives a real build the way a person drives it: a cold start filling a feed from the public internet, a packaged bundle launched through LaunchServices, and an account's contact list edited and read back off a relay with an independent tool.

scripts/acceptance.sh

It is not part of CI. It publishes signed events to public relays, so it needs a throwaway account rather than a checkout, and it says so and skips rather than guessing. The details are in the script.

Plaza is a Native SDK app: plain Zig for the logic and the feed (src/main.zig), declarative .native markup for the static screens, rendered natively, no browser, no Electron.

Linux builds and tests in CI on every change. Windows is not in the matrix: the relay transport resolves hostnames through libc getaddrinfo, which Zig's standard library does not declare for Windows, so nothing depending on the library links there (zig-nostr/nostr#59). Packaged releases for either come later regardless.

License

MIT, see LICENSE.