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If you want a Checkly alternative that checks an agent's change before it merges, inside the running app, Reticle is built for that. If you want production monitoring from global locations with alerts and status pages, Checkly is the right tool, and Reticle is not an uptime monitor.
What Checkly does
Checkly calls itself "The active reliability layer for developers & agents" (checklyhq.com). It is monitoring as code: API, browser and multistep checks written in TypeScript and Playwright, deployed from a CLI, Terraform or Pulumi, and run on a schedule from global locations with alerting. Playwright Check Suites turn existing Playwright tests into scheduled monitors.
It has a remote MCP server for checks, results, root-cause analyses, status pages and incidents, plus agent skills for Claude, Cursor and Codex (MCP docs).
Pricing is public: Hobby free, Starter $24 a month, Team $64 a month, Enterprise custom (pricing, checked 2026-10-25). The CLI is open source (Apache-2.0); the service is not.
What Reticle does
Reticle checks an AI coding agent's change from inside the running web app and returns a verdict with evidence. It reads the network calls, the application state and the console, and on React and Svelte it names the file:line to fix.
Your agent calls it through MCP while it works. Flows it drives are saved and replay deterministically, with no model in the loop. It also drives sites you don't own, reading network, console and DOM there; app state and file:line need its SDK in your build. The SDK is open source (Apache-2.0); the hosted platform runs the same checks on previews and pull requests.
Checkly vs Reticle at a glance
| Checkly | Reticle | |
|---|---|---|
| When it runs | On a schedule, after deploy, from global locations | While the agent works, in CI, and on previews |
| What it checks | Black-box API and browser checks | Network, app state, console and DOM after each step |
| Alerting, status pages, incidents | Yes | No |
| Agent integration | Remote MCP server and skills | MCP tools the agent calls while it works |
| Points to the fix | The failing check, with AI root-cause summaries | The failing request or state, and file:line on React and Svelte |
| Open source | CLI only (Apache-2.0) | SDK Apache-2.0; server FSL-1.1 |
| Pricing | Free; $24/mo; $64/mo | Start free, no card; open-source SDK free |
Where Checkly is the better choice
- You need to know production is up. Checkly runs from global locations on a schedule and alerts you. Reticle checks changes before they ship; it does not watch production.
- You want status pages and incident tooling. Those are part of Checkly. Reticle has none.
- You already have Playwright tests. Checkly reuses them directly as monitors.
- You want zero setup in the app. Checkly's checks are black-box with nothing in your build.
Where Reticle is the better choice
- You want to catch it before merge. Reticle runs while the agent works, so the change is checked before anyone reviews the PR, not after users hit it.
- The failure is inside the app. A double request, a store that disagrees with the screen, a silent console error. Reticle reads those from inside the page; a black-box check sees only what reaches the page or the API.
- You want the fix location. The verdict names the failing request or state and, on React and Svelte, the source line.
- You want flows without writing them. Reticle saves the flows the agent drives and replays them with no model in the loop, at about 480 tokens for four flows.
On 88 seeded bugs, Reticle caught 85 with no false alarms; two of the other three are traps a correct tool must not flag, and one is a genuine miss. The method is in the benchmark scorecard.
Can you use both?
Yes, and they sit at different ends of the pipeline. Reticle checks each change before it merges; Checkly keeps watching production after it deploys. A regression that slips past one has a second chance to be caught by the other.
For the case for checking behaviour before review, see AI verification. For other tools, see the Datadog Synthetics alternative page and all alternatives.
Try Reticle in five minutes
Paste one line to your coding agent, and it installs and wires the SDK in your app:
Follow https://raw.githubusercontent.com/reticlehq/reticle/main/SKILL.md
Or run npx @reticlehq/core init yourself. The README has the details.
FAQ
What is the best alternative to Checkly?
The best alternative to Checkly depends on the job. For production synthetic monitoring, look at Datadog Synthetics, Grafana Synthetic Monitoring or New Relic Synthetics. For checking an agent's change before it merges, inside the running app through network, state and console, Reticle fits. Monitoring and pre-merge verification are different jobs.
Is Reticle a synthetic monitoring tool?
No, Reticle is not a synthetic monitoring tool. It does not run scheduled checks from global locations, send alerts or host status pages. It verifies changes before they ship, while a coding agent works, in CI and on previews. Teams that need production monitoring keep a tool like Checkly for that.
How is Reticle different from Checkly?
Reticle is different from Checkly in when and where it checks. Checkly runs black-box checks against production on a schedule. Reticle runs inside the app before merge and reads requests, state and console after each step, then names the source line to fix, so problems are caught before users see them.
Why Reticle
Your agent says it works. Reticle checks.
- Checks each change inside the running app: network, state and console, not a screenshot.
- Returns a pass or fail with the evidence and the file:line to fix.
- Open-source SDK on your machine, or the platform on every preview and PR.
No credit card required.