straylight
straylight shows how good your connection is from the menu bar: latency, jitter, and packet loss, to your router and to the internet, side by side. For Apple Silicon Macs.
Is it the Wi‑Fi, or the internet? straylight answers that at a glance.
straylight is a sibling to flatline. flatline shows how much traffic is moving; straylight shows its quality. It follows the same rules: one narrow job, Apple Silicon and macOS 27 only, no root helper, and close to zero cost when idle.
Status: 1.0 is out. See the CHANGELOG and the PRD.
Features
- Router and internet measured together, with a plain verdict: Good, Internet problem, Internet down, Local network problem, or Offline
- Two internet hosts from different providers, so one provider's bad day doesn't look like your ISP's
- Latency (now, median, p95), jitter, and loss per target, with a 60-second trace. A lost ping drops the trace flat.
- History: per-minute stats for 7 days, hourly stats and a log of outages and spikes for 30 days (up to 90), with CSV export to send to your ISP
- Wi‑Fi context: signal strength, noise and transmit rate, so you can see when loss follows a weak signal
- Optional custom targets, such as a VPN endpoint or a game server
- Optional notifications for outages
- Fixed-width, monochrome menu bar; terminal-style popover with a phosphor accent
- Launch at login, automatic updates via Sparkle
- No telemetry, no root helper, no kernel extensions
Network traffic
straylight sends small ping packets (56 bytes) to the targets you choose: your router, 1.1.1.1 and 8.8.8.8 by default, plus 1.1.1.1 over IPv6 on networks that have it. That's one per target per second on power and one every 5 seconds on battery, briefly once a second after a network change or a lost ping. It stops while the screen is locked unless you turn on overnight monitoring. If a network blocks ping, it times a normal HTTPS connection instead. History stays on your Mac unless you export it.
Requirements
- macOS 27 or later
- Apple Silicon (M1 or newer)
Install
Download the latest version from straylight.banast.as, open the DMG and drag straylight to Applications. It's signed and notarized, and updates itself.
Building from source
Requires Xcode 27+ and XcodeGen.
brew install xcodegen
xcodegen generate
open Straylight.xcodeproj
Unit tests run without Xcode:
swift test --package-path Packages/StraylightKit
straylight-probe is a development tool for checking the probes against ping; it isn't part of the app:
swift run --package-path Packages/StraylightKit -c release straylight-probe -c 60 1.1.1.1
--monitor 120 runs the whole measuring pipeline for two minutes and prints the verdict and each target's stats after every round. Add --history file.sqlite to record history there, and --export file.sqlite 30 prints the CSV for the last 30 minutes. --tune file.sqlite 7 shows how often each "Bad" threshold would have fired over the last 7 days, for tuning them. Its source lists the other options.
The app reads a few environment variables for checking its drawing without clicking: STRAYLIGHT_SNAPSHOT=bar.png writes each menu bar image, STRAYLIGHT_POPOVER_SNAPSHOT=popover.png writes the popover after 15 seconds (STRAYLIGHT_POPOVER_PAGE=settings, first-run, paused or wifi picks what it shows), STRAYLIGHT_HISTORY=test.sqlite uses another history database, STRAYLIGHT_HOSTS=1.1.1.1,192.0.2.1 sets the internet hosts, STRAYLIGHT_ON_BATTERY=1 acts as if on battery, and STRAYLIGHT_LOCK_TEST=10,40 acts as if the screen locked at 10 s and unlocked at 40 s. The comments in StatusItemController.swift, AppModel.swift and SystemState.swift list the rest.
Debug builds are ad-hoc signed and run on any Mac. Release builds are signed with the maintainer's Developer ID: scripts/release.sh tests, archives, signs, notarizes and staples the app and a DMG in dist/ (--skip-notarize for a dry run), scripts/bump-version.sh 0.2.0 sets the next version, and scripts/deploy-site.sh publishes the site, the update feed and the releases (--no-deploy to assemble dist/site for a local look). STRAYLIGHT_FEED_URL=http://localhost:8000/appcast.xml points the app at a local feed, for testing an update without publishing, and STRAYLIGHT_POPOVER_TIMING=5 opens and closes the popover five times and logs how long each first frame took.
License
MIT. See LICENSE.
