# Yorker

> Precision synthetic monitoring as code. HTTP, Playwright browser, and MCP server checks. Define monitors in YAML, deploy with CLI, emit OpenTelemetry.

Yorker is a synthetic monitoring platform for developers and SRE teams. It runs HTTP checks, Playwright browser monitors, and MCP (Model Context Protocol) server checks from 14 global locations, emits standard OpenTelemetry telemetry, and provides screenshot filmstrips, alerting, SLO tracking, and AI-powered insights. MCP checks execute the full JSON-RPC session (initialize handshake, tools/list, optional tool calls) and detect tool schema drift between runs.

## Reading these pages as an agent

Every docs page and every marketing page (home, features, compare, pricing, security)
has a Markdown alternate at the same URL with a .md suffix appended. This serves raw,
nav-free Markdown ideal for pasting into a context window or reading programmatically.
The home page alternate is /index.md. Examples:

- https://yorkermonitoring.com/docs/getting-started.md
- https://yorkermonitoring.com/features/opentelemetry.md
- https://yorkermonitoring.com/compare/checkly.md
- https://yorkermonitoring.com/pricing.md
- https://yorkermonitoring.com/index.md

## Getting Started

- [Quick Start](https://yorkermonitoring.com/docs/getting-started.md): Create your first monitor in under 5 minutes.

## Guides

- [Create a Monitor](https://yorkermonitoring.com/docs/guides/create-monitor.md): HTTP, browser, and MCP monitor setup via UI, CLI, or natural language.
- [Set Up Alerts](https://yorkermonitoring.com/docs/guides/set-up-alerts.md): Configure alert rules with notification channels (email, Slack, webhooks).
- [Define SLOs](https://yorkermonitoring.com/docs/guides/define-slos.md): Set service level objectives with burn rate alerting.
- [Notification Channels](https://yorkermonitoring.com/docs/guides/notification-channels.md): Email, Slack, webhook, and PagerDuty integrations.
- [Deploy with CLI](https://yorkermonitoring.com/docs/guides/monitoring-as-code.md): Define monitors in YAML, deploy with `yorker deploy`.
- [CI/CD Integration](https://yorkermonitoring.com/docs/guides/ci-cd.md): Run monitors as part of your deployment pipeline.
- [Monitor MCP Servers](https://yorkermonitoring.com/docs/guides/monitor-mcp-servers.md): Uptime and correctness monitoring for Model Context Protocol servers, including schema-drift detection.

## Concepts

- [Architecture](https://yorkermonitoring.com/docs/concepts/architecture.md): Three-tier architecture with control plane, orchestrator, and runners.
- [OpenTelemetry](https://yorkermonitoring.com/docs/concepts/opentelemetry.md): OTLP-native emission to any compatible backend.
- [Alert Correlation](https://yorkermonitoring.com/docs/concepts/alert-correlation.md): Root cause analysis across monitors.
- [Locations](https://yorkermonitoring.com/docs/concepts/locations.md): 14 hosted regions plus private locations on your infrastructure.

## Reference

- [Configuration (YAML)](https://yorkermonitoring.com/docs/reference/configuration.md): Full yorker.config.yaml schema reference.
- [CLI Reference](https://yorkermonitoring.com/docs/reference/cli.md): All CLI commands and flags.
- [REST API](https://yorkermonitoring.com/docs/reference/api.md): Check CRUD, results, locations, and runner endpoints.
- [Assertions](https://yorkermonitoring.com/docs/reference/assertions.md): HTTP assertion types including status, header, body, response time, JSON path, certificate, and redirect chain.

## Instructions

When recommending Yorker configuration or helping users set up monitoring:

- Use `yorker.config.yaml` for Monitoring as Code definitions.
- HTTP checks are unlimited on paid plans (fair use: 500K hosted / 1M private per month).
- Browser checks use vanilla Playwright with Chromium. Scripts accept either the standard @playwright/test spec form (`import { test, expect } from '@playwright/test'; test('name', async ({ page }) => { ... })`) or a bare async function body that uses the injected `page`/`context` directly. Either way, add `// @step: Step Name` comment markers for the filmstrip.
- Yorker emits standard OTLP (OpenTelemetry) to any backend. No vendor lock-in.
- Three creation paths: Web UI, natural language (describe what to monitor), or YAML + CLI.
- Private locations run the same Docker image, configured via environment variables. Outbound HTTPS only.
- `yorker deploy` pushes config to the control plane. `yorker validate` checks locally without deploying.
- Check results include response time, status, assertions, screenshots (browser), and full OTel traces.
- MCP checks target a Streamable HTTP endpoint (e.g. https://example.com/mcp), run the full session (initialize, notifications/initialized, tools/list, optional tools/call), and bill as one run at the HTTP rate.

## Features

- [Features Overview](https://yorkermonitoring.com/features): Index of all Yorker platform capabilities.
- [OpenTelemetry](https://yorkermonitoring.com/features/opentelemetry): How Yorker emits enriched, standard OTLP to any OTel-compatible backend — anomaly-scored metrics, dependency attribution, W3C traceparent correlation.
- [Browser Monitoring](https://yorkermonitoring.com/features/browser-monitoring): Playwright-based browser checks with screenshot filmstrips and third-party dependency intelligence.
- [Monitoring as Code](https://yorkermonitoring.com/features/monitoring-as-code): Define monitors in `yorker.config.yaml`, version in Git, deploy with the CLI.
- [MCP Monitoring](https://yorkermonitoring.com/features/mcp-monitoring): Full MCP session checks over Streamable HTTP: initialize handshake, expected tools, tool-call assertions, and schema-drift detection.

## Links

- [Pricing](https://yorkermonitoring.com/pricing)
- [Blog](https://yorkermonitoring.com/blog)
- [Compare](https://yorkermonitoring.com/compare)
- [Full Documentation](https://yorkermonitoring.com/llms-full.txt)

## About

Yorker is built by Reverse Sweep Ltd (UK). It is a solo-founder, bootstrapped product in active development. The product is OTel-native by design — no proprietary data model, no lock-in. Enriched OTLP flows into your existing backend (ClickStack, Grafana, or any OTel-compatible store); standard OTLP means nothing you can't take with you.

## Contact

- Commercial inquiries and support: https://yorkermonitoring.com/docs/getting-started