Loggerhead
Download

Native Swift · Built for agentic development

Observability that never leaves your Mac.

Loggerhead is a Mac app that watches the software you run on your machine. It collects the logs, numbers, and request traces your app produces and shows them in one clear window. Your AI coding tool can read the same data. Nothing leaves your Mac.

Download for macOSRead the docs
  • macOS 15 or later
  • Apple silicon and Intel
  • Notarised, free to start
  • Native Swift, no runtime to install

Three signals, one window

Logs, metrics, and traces that already know each other.

Click a log line and jump to its trace. Click a span and see the logs it emitted. One local store keeps every signal in the same time base, so you stop stitching tabs together.

Dashboard
The Dashboard page in Loggerhead. Four tiles show logs a minute, metrics a minute, traces a minute, and the error rate. A stacked area chart shows the telemetry volume of the last hour. Panels list the collectors, two active alerts, and five improvements. A table ranks four services by requests, errors, and p95 latency.
  • The log list in Loggerhead. Each row shows a severity icon, the time, a trace id, the service, and the message.

    Logs that stream, not scroll

    Severity tints, service colours, and filters for level and service. Search the message text, pause the stream, and open one line to read its fields.

  • A metric chart in Loggerhead. Three services draw one line each for http.server.request.duration, with the label filter above the chart.

    Metrics with a memory

    Counters, gauges, and histograms land in DuckDB. Pick any window, group the series by label key, and compare services without an exporter in the middle.

  • A trace waterfall in Loggerhead. Six spans of a POST /checkout request, with the failed stripe.charges.create span marked in red.

    Traces you can actually read

    A waterfall per request, spans grouped by service, and the slow one highlighted. Jump from a span to the logs it produced in one click.

Built for agentic development

Give your coding agent eyes on the running app.

AI coding tools guess when they cannot see. Loggerhead gives them a window into your running app through MCP, an open standard those tools already speak. The tool reads what your app actually did, then fixes the real problem.

WORKS WITH

  • Claude Code
  • Cursor
  • Codex
  • Windsurf
  • Any MCP client

One root, many branches

Push telemetry in, or let Loggerhead pull it.

The app runs the receiver on localhost. Docker, Kubernetes, another Mac, or your app's SDK pushes into it as a branch. Loggerhead can also scrape a URL on a schedule, so tools that only expose metrics still show up. Every source gets an ID, so you always know where a record came from.

Collector map
The Collector map page in Loggerhead. The receiver on ports 4317 and 4318 sits between three collectors, local, staging, and a Prometheus scrape, and the DuckDB file on disk. Each collector lists the services it carries and its record rate.

The app draws the same picture from live traffic. Every collector shows the services it carries, its record rate, and the moment it last spoke.

Telemetry linting

Lint your telemetry before production sends you the bill.

Most apps log too much and measure the wrong things. Loggerhead reads what your app emits and points at the junk: noisy debug lines, labels with thousands of values, secrets in plain text, and errors that lost their trace. Every finding comes with the fix already written. Copy it into the AI tool in your project, and the agent changes the code.

Improvements
The Improvements page in Loggerhead. Five findings: a high log volume on checkout-api, an email address in an auth log field, a high-cardinality http.route label, payments logs without trace context, and a stale queue.depth metric. Each finding carries a written fix.
  1. 1.Loggerhead finds itRules read the last window of real telemetry and name the problem, the service, and the field.
  2. 2.You copy the fixEvery finding carries the fix in plain words. One copy, and no query language to learn.
  3. 3.Your agent applies itPaste it into Claude Code, Cursor, Codex, or Windsurf. The agent edits the logger or the collector config in your project.
  • Cut the noiseDrop and sample the lines nobody reads. Keep the ones that explain a failure.
  • Catch secrets earlyEmails, tokens, and card numbers get flagged before they reach anyone's logs.
  • Keep traces wholeEvery error links to the request that caused it. No more orphan logs.
  • Fix it where the code isThe fix goes to the tool that already has your project open, so the change lands in your repository.

Made for the person who runs the app

A development environment for how your code behaves.

Loggerhead is not a production observability platform, and does not want to be. It is the window you keep open next to your editor while you build, test, and stage.

  • Solo developers

    One native app, one window, zero infra. See what your side project actually does before you ship it.

    • Runs with your app, not next to a cluster
    • Nothing to host, nothing to pay per GB
    • Query a week of local traffic in milliseconds

  • Staging and preview

    Point a staging cluster at your Mac over a tunnel and get a full picture of a release before it goes live.

    • Branch collectors for Docker and Kubernetes
    • Per-collector attribution on every record
    • Alerts and improvement hints on real traffic

  • Agent-first workflows

    Give Claude Code or Cursor the same view you have. The agent reads logs and traces over MCP, then acts on facts.

    • MCP server included, one click to add
    • Search, aggregate, and trace lookups as tools
    • Local only, so the agent never sees prod

Honest scope: DuckDB on one Mac. Great for local and staging traffic. Keep your production platform for production.

Up in three steps

From download to your first insight in under two minutes.

  1. Install the app

    Download, open, and drag Loggerhead to Applications. The receiver, the store, and the MCP server all run inside the app. There is nothing else to install.

  2. Choose what to watch

    Inside Loggerhead, pick a source: an app on this Mac, Docker, Kubernetes, or a URL to scrape. Loggerhead picks a free port for you.

  3. Connect your AI coding tool

    Pick the tool you use and click once. It can then read what your app did and fix real problems.

    Add Loggerhead to Claude Code

    Works with any tool that supports MCP.

Buy once, keep it

One licence. No seats, no ingest bill, no renewal.

  • Free

    $0forever

    Everything a solo developer needs to see one app on one Mac.

    • Logs, metrics, and traces
    • The Loggerhead receiver and one branch collector
    • One pull source and one scrape endpoint
    • MCP server for your coding agent
    • Support by email
    Download free

  • Pro

    $79one-time · up to 3 Macs

    For staging traffic, many collectors, and the alerting that catches a bad release.

    • Everything in Free
    • Unlimited branch collectors
    • Unlimited pull sources
    • Standalone receivers and unlimited scrape endpoints
    • Keep data as long as you like
    • Telemetry linting, with the fix written for your AI tool
    • Alerts, native notifications, and menu bar status
    • A year of updates, then keep the version you have
    Buy Loggerhead