Design system
Every part Signal ships, rendered once with real content: 12 sections, 12 primitives, 45 tokens per mode.
src/components · src/components/ui · src/theme.css · src/fonts.ts
45 variables per mode in src/theme.css: 18 colour, 24 type, three shape and weight. These chips read them live.
--background
--foreground
--card
--card-foreground
--primary
--primary-foreground
--secondary
--secondary-foreground
--muted
--muted-foreground
--accent
--accent-foreground
--primary
--primary-hover
--primary-active
--surface-tint
--font-text · IBM Plex Sans
Aa Bb Cc 0123
--font-mono · IBM Plex Mono
Aa Bb Cc 0123
--radius · --radius-inner
8px outer, 5px inner, never the other way round
--border
one hairline weight, everywhere
--ring · --shadow-color
2px ring offset 2 · shadows never use --background
Each section rendered once, at the width and with the content it ships with.
Sticky nav: wordmark, five links, a star chip and two buttons. Below md it collapses into a JS-free details menu.
The home masthead: badge, headline, install row and a live sgl watch transcript that overhangs the container.
When p95 moves, the commit that shipped 24 seconds earlier is already next to it.
brew install signalhq/tap/sgl8.4 MBfree for solo devs · no card · self-host the collector
$ sgl watch --env prod --since 15m prod · us-east-1, eu-west-1 · 3 services ok api-gateway p95 184ms err 0.02% ▁▂▁▁▂▁ ok checkout p95 221ms err 0.05% ▁▁▂▁▁▁ !! payments-worker p95 912ms err 1.31% ▁▂▄▆██ ▲ regression payments-worker · p95 +611ms baseline 301ms (24h rolling) onset 14:02:11Z · 11m ago deploy 8f21c4e "retry budget for webhooks" @nadia · 24s before onset → sgl trace payments-worker --deploy 8f21c4e
The hero's regression narrative, drawn: a p95 series flat in its 24h envelope, the deploy marker, then the step up 24 seconds later. Inline SVG computed from two point arrays, token-coloured, server-rendered and static.
Eight data sources on a full-bleed hairline grid, one lucide glyph each, describing what the source does.
No proprietary agent: anything that speaks OTLP works the day you install it, and the rest pipes through sgl ingest.
Four cards carrying nine lines of real YAML, TypeScript and shell, a named outcome, then three supporting claims.
What you get
Signal is a CLI first: everything you can click, you can also review in a pull request.
Every release lands on the timeline with its sha, author and diff. When a regression starts inside a deploy window, Signal attributes it before you open a dashboard.
# runs after your existing deploy step
- name: Mark deploy in Signal
uses: signalhq/mark-deploy@v2
with:
service: payments-worker
env: prod
sha: ${{ github.sha }}
by: ${{ github.actor }}
fail-on-regression: trueOne import at the top of your entrypoint. The SDK wraps HTTP, gRPC and your database driver, and adds nothing to the request path but a buffer write.
import { init } from "@signal/node";
init({
service: "payments-worker",
env: process.env.SIGNAL_ENV,
// all errors, half the slow ones, 1% of the rest
sample: { errors: 1, slow: 0.5, baseline: 0.01 },
endpoint: process.env.SIGNAL_ENDPOINT,
});Thresholds are code, reviewed in pull requests, versioned with the service they watch. No click-ops, no drift between staging and prod.
import { alert, p95 } from "@signal/config";
export default [
alert({
when: p95("checkout.submit").above("400ms"),
for: "5m",
notify: ["#oncall-payments", "escalate:tier1"],
}),
];The same query language in the CLI, the dashboard and the API. Pipe it to jq, commit it as a saved view, or page it into an incident doc.
$ sgl query 'p95(latency) by route' \
--service checkout --since 24h
route p95 n 24h
/checkout/submit 412ms 18.2k +38%
/checkout/quote 121ms 44.9k -2%
/checkout/receipt 88ms 12.1k +1%
/checkout/webhook 118ms 6.4k -1%
/checkout/refund 204ms 2.1k +4%“Time to attribution went from forty minutes to under three.”
Head sampling throws away exactly the requests you needed. Signal decides after the fact: every error, every p99 outlier, a slice of the boring remainder.
sgl config sampling
The collector is a single static binary: no queue, no cluster to babysit. On the self-hosted plan raw traces never leave your VPC.
sgl collector verify
Priced per ingested gigabyte after sampling, not per host and not per seat. Estimate it against your current volume before you commit.
sgl cost --estimateestimator
Three plans on one price model, then the definition of a billed gigabyte beside the ledger of things that are never metered.
Plans
Ingested gigabytes after sampling is the only meter on the account.
$0
Up to 5 GB a month after sampling. There is no expiry on it.
$0.42/ GB
Every gigabyte after sampling. No minimum, no seat count, no host count.
Aggregates only
The same $0.42 meter, on what the collector forwards. Raw spans never leave your VPC.
The collector measures the compressed bytes it accepts, after your sample rates have already thrown work away. A span you never sent is a span you never pay for.
Retention is included rather than metered: thirteen months on the usage plan, thirty days on the free tier. Storing a gigabyte for a year costs the same as storing it for a week.
Run sgl cost --by service to see which service is spending it.
A client island. Raw volume and sample rate go in, the invoice arithmetic comes out; the default state is the same 107.1 GB and $44.98 the sgl cost transcript prints.
Estimator
Every figure below is the arithmetic on your invoice, not a range.
Sample rate
Sampling is set per service in signal.config.ts. Every error and every p99 outlier is kept whatever the rate, so the slice you drop is the boring remainder.
Estimated month
107.1 GB at $0.42/GB
Up to 5.0 GB a month after sampling costs nothing. Above that line every gigabyte is billed, including the first five.
Already sending spans? Run sgl cost --estimate and it reads the last thirty days off your own account.
The company surface: four contact routes with stated response times, a full-bleed operations band, and the legal minimum at #legal.
Support
Pick the one that matches the problem and it reaches an engineer, not a queue.
Instrumentation that will not attach, a query that returns nothing, a sample rate that reads wrong. Paste the output of sgl doctor and skip the first three replies.
Vulnerability reports and coordinated disclosure. Encrypt with the key at fingerprint 3C7A 55E1 90BD 4F26 if the report contains customer data.
Ingest is dropping spans, alerts are not firing, the collector will not start. Usage-plan accounts page an on-call engineer directly.
Invoices, VAT numbers, purchase orders and the one question everyone asks: which service spent the gigabytes. Include the invoice number.
support and billing Mon to Fri, 09:00 to 18:00 CET · incidents and security any hour, any day
terms and privacy · last updated 6 Aug 2026
Requests for the DPA, the sub-processor list or a deletion confirmation go to legal@signal.sh. Account deletion is also a command: sgl org delete --confirm.
Dated release entries with icon-marked tags. Shown here in preview: variant='full' swaps the three latest for all eight, adds the migration transcript and the tag filter.
Changelog
216 releases since 2024, each written by the person who shipped it.
One repository can now emit a deploy event per service, so a forty-package monorepo stops blaming every regression on the same commit.
Processes that never restart drifted above their configured baseline rate, up to 4x on workers older than a week. Thanks to @tvoss for the reproduction.
An alert now arrives carrying the three slowest traces that triggered it, so the notification is the first step of the investigation rather than a reason to go find one.
The closing panel: headline, two buttons, an init command and four answers to cost, risk and effort.
Install the CLI, point one service at the collector, and the next deploy annotates itself.
sgl init --service payments-workerPage-scale: sidebar, article, on-this-page rail and the full-bleed payoff band. Shown here in variant='quickstart'; variant='cli' swaps in the seven-command reference and its own transcript.
This guide takes a Node service from zero to a deploy-annotated latency timeline. It takes about ten minutes, and nothing here is reversible in a way that should worry you — the SDK is a no-op until an ingest key is present.
The CLI is a single binary. It is the same tool your CI uses, so install it the same way in both places.
brew install signalhq/tap/sgl
# or: curl -fsSL https://get.signal.sh | sh
sgl --version
# sgl 2.4.0 (darwin/arm64)A service is the unit everything else hangs off: spans, alerts, deploys and cost. Create one per deployable, not per repo.
sgl login
sgl service create payments-worker --env prod
# wrote SIGNAL_INGEST_KEY to .env.local
# scoped to payments-worker/prod
# rotate with: sgl key rotateThe SDK wraps HTTP, gRPC and your database driver. It has to load before your application code, which is what the --import flag is for.
import { init } from "@signal/node";
init({
service: "payments-worker",
env: process.env.SIGNAL_ENV ?? "dev",
});{
"scripts": {
"start": "node --import ./instrument.js dist/app.js"
}
}Running the collector yourself? Set SIGNAL_ENDPOINT before this step. In self-hosted mode the SDK never opens a connection to signal.sh — the checks to run first are under sgl collector.
This is the step that makes the rest of Signal worth having. Run it at the end of your deploy job, after traffic shifts.
sgl deploy mark \
--service payments-worker \
--env prod \
--sha "$(git rev-parse HEAD)" \
--by "$CI_ACTOR"Once a deploy and a few thousand spans are in, the timeline can attribute a change to a release. Add --json to the same command to gate a rollout in CI.
sgl watch --env prod --since 15m
sgl watch --env prod --since 15m --json | jq '.regressions'One deploy and a few thousand spans later, the timeline stops reporting and starts attributing.
$ sgl watch --env prod --since 15m ok payments-worker p95 301ms err 0.04% ▁▂▁▁▂▁ ▲ regression payments-worker · p95 +611ms baseline 301ms (24h rolling) onset 14:02:11Z · 11m ago deploy 8f21c4e "retry budget for webhooks" @nadia · 24s before onset → sgl trace payments-worker --deploy 8f21c4e
The last line is the next command. That is the whole product.
The ui/ parts every section is built from, in one frame.
Every ui/ part in the states it ships with. ui/container, ui/type and ui/logo are structural: they render in the shell around this page.
ui/button · variant
ui/theme-toggle · ui/copy-button
brew install signalhq/tap/sglui/badge · ui/inline-code
sgl trace --deploy 8f21c4eui/code-block
import { init } from "@signal/node";
init({ service: "payments-worker", sample: { errors: 1 } });ui/terminal-window
$ sgl status --env prod ok api-gateway p95 184ms !! payments-worker p95 912ms
ui/section-heading
Alerts
Route by deploy author, not by rota. The commit already knows who to wake.
ui/page-hero
Docs
From an uninstrumented Node service to a deploy-annotated latency timeline.
counterweight slot
Every masthead fills its right half. A1, never the retired A2.
Three link columns, the product blurb, a build string and a status line. Every link resolves to a page or an anchor the theme ships. Rendered in place as the page shell.