# Building OpenStatus: A Deep Dive into Our Infrastructure Architecture

Dec 29, 2024 \| by [Thibault Le Ouay Ducasse](https://bsky.app/profile/thibaultleouay.dev) \| \[engineering\]

## Infrastructure Overview

OpenStatus is a synthetic monitoring platform designed with resilience, scalability, and efficiency in mind. Our users rely on us to provide real-time insights into their service health, making it essential to maintain a robust and performant infrastructure.

In this post, we'll take a deep dive into our infrastructure architecture, exploring the key components, managed services, and design principles that power OpenStatus.

## Application Landscape

Our platform consists of several interconnected applications, each designed for a specific purpose:

1. **Frontend Ecosystem**:
   
   - A NextJS application that powers our marketing site, user dashboard, and status page hosted on [Vercel](https://vercel.com/).
   - An Astro + Starlight-powered documentation application hosted on [Cloudflare Pages](https://pages.cloudflare.com/).

We chose Vercel for the Next.js application because it performs exceptionally well there, the DX is great. And we selected Cloudflare Pages for the documentation since it is a static site and it's super cheap.

2. **Backend Infrastructure** All our backend services are hosted on Fly.io.

- API server: Our public API and our alerting engine
   - Probes/Checker: a golang app deployed globally to monitor your service
   - Screenshot app: a service that takes screenshot of your website when we detect an downtime (Playwright)
   - Workflow engine: a server that handles the workflow of alerting, and our internal workflows (email automation).

We chose Fly.io for our backend services because it's a great platform for deploying globally distributed services. It's also very easy to deploy and manage. We are planning to add more providers (e.g. Koyeb) to our probes to have a more resilient system.

## Managed Services

We also rely heavily on managed services to avoid handling it ourselves. Here are the services we use:

### Scheduling

Recognizing the critical nature of monitoring, we've heavily rely on CRON to ensure timely checks:

- **Cron Jobs**: Currently using Vercel Cron, with plans to migrate to Google Cron for an enhanced user experience (better UI e.g. we can see when the cron ran, retry policy).

### Queue Architecture

Due to the critical nature of checks, we are using a queue to handle task processing and retry logic:

Every check is pushed to a queue and processed by our probes. If the probe fails to process the check, it is retried 3 times before being marked as failed.

- **Job Queue**: Google Task Queues provide our distributed task management, with strategically segmented queues for different check frequencies

We've implemented a granular queue system to ensure efficient task processing, each queue is dedicated to a specific check frequency (e.g. every minute, every 10 minutes).

### Data Infrastructure

We also don't want to handle the data infrastructure by ourselves. We rely on managed services for that:

- **Primary Database**: [Turso](https://turso.tech/?ref=openstatus.dev), providing a cost efficient data storage solution. We love the fact that's it's hosted SQLite database. It's just a file we can embedded in our services and sync it periodically.
- **Analytics Database**: [Tinybird](https://www.tinybird.co/?ref=openstatus.dev), enabling complex analytical queries and insights.

## Design Philosophy

Our infrastructure design is driven by several key principles:

- **Resilience**: Ensuring high availability and fault tolerance
- **Scalability**: Architectural choices that allow seamless growth
- **Cost-Efficiency**: Leveraging managed services and cloud credits
- **Performance**: Optimizing each component for maximum efficiency.

## How much does it cost us?

Our current monthly cost is around $328. This includes:

- Vercel: $40, we are two members in the team, so we had to upgrade to the team plan.
- Fly.io: $154 36\*4 (all our probes at $4 average, not all regions cost the same) + $10 (for the api server)
- Google Cloud Platform: $0 (We are still using the free credits, but we expect to pay around $50 for the queue)
- Tinybird: $100
- Turso: $29
- Cloudfare: $5

## Conclusion

Building a resilient synthetic monitoring platform is hard. It's not just a $5 VPS that you can deploy and forget. It requires a more complex infrastructure to be able to provide a reliable service.

The drawback of this approach is the complexity of providing an easy self hostable services. Which is annoying because we are an open-source project and we want to provide a self-hostable version of OpenStatus. But we are working on community edition that will be easier to deploy.

_Want to start monitoring your services with OpenStatus? [Sign up for free](/content/app/login?ref=blogpost-infra/index.html) and get started today!_