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If you want a Greptile alternative for the testing side, one that checks a change inside the running app (requests, state, console) while your agent is still working, Reticle is built for that. If you want AI code review and an end-to-end agent on every pull request from one bot, Greptile is the stronger choice. Reticle does not review code.
What Greptile does
Greptile describes "AI agents that review and test pull requests with full context of the codebase" (greptile.com).
It indexes your codebase as a graph and runs review agents on each pull request. TREX, "an end-to-end testing agent", works out which user flows a PR affects, starts the app in a sandbox built from your environment, and uses it like a person: clicking, typing and watching the screen. It posts what passed or failed with logs, screenshots, traces and video (TREX docs).
Pricing is a free Starter tier, Pro at $1 per credit, and Enterprise custom; a TREX run costs 3 credits and is charged only when a flow reaches pass or fail (pricing). Greptile is not open source.
What Reticle does
Reticle checks an AI coding agent's change and returns a pass or fail with evidence. It reads network calls, console, DOM and application state, and on React and Svelte it names the file:line to fix.
Your agent calls it over MCP while it works. Saved flows replay deterministically in CI and on the hosted platform for previews and pull requests. It works on your own app and on sites you don't own (its own browser, SDK injected); app state and file:line need the SDK in your build.
Greptile vs Reticle at a glance
| Greptile (review + TREX) | Reticle | |
|---|---|---|
| Code review | Yes, the main product | No |
| When testing runs | On each PR, in a sandbox | While the agent works, in CI, on previews |
| How the test sees the app | Watches the screen like a user | Inside the page: network, state, console, DOM |
| Picks what to test | Infers affected flows from the PR | Replays the saved flows covering the change |
| Evidence | Logs, screenshots, traces, video | The deciding requests, state and console; file:line on React and Svelte |
| Re-runs | An agent drives each run, credit-metered | Saved flows replay with no model, 0% flake over 8 replays |
| Open source | No | SDK Apache-2.0; server FSL-1.1 |
| Pricing | Free Starter; $1/credit; TREX run 3 credits | Start free, no card; open-source SDK free |
Where Greptile is the better choice
- You want code review. Greptile reviews the diff with codebase context. Reticle does not read or review code.
- You want one bot on the PR that reviews and tests together.
- You want nothing added to the app. TREX runs from the PR in a sandbox.
- You want video evidence on the PR that a reviewer can watch.
Where Reticle is the better choice
- You want the check before review. The agent verifies inside its own loop, so the PR arrives with the flows already proven.
- The failure is not on screen. An agent that watches the screen sees a correct page when a request fired twice or a write never persisted. Reticle reads the request count, the state and the console.
- You want the same answer every run. Saved flows replay with no model; re-verifying four flows costs about 480 tokens (scorecard).
Can you use both?
Yes, and they barely overlap. Greptile reviews the code and runs a per-PR agent; Reticle verifies behaviour inside the app before and during the PR. Why a screen that looks right is not proof is the subject of why a green check isn't proof.
For other per-PR testing agents, see the DevAssure alternative and the alternatives hub.
Try Reticle
Paste one line to your coding agent and it installs and wires the SDK:
Follow https://raw.githubusercontent.com/reticlehq/reticle/main/SKILL.md
Or run npx @reticlehq/core init. The README has the details.
FAQ
What is the best alternative to Greptile?
The best alternative to Greptile depends on whether you need review or testing. For code review, compare other AI review bots. For verifying behaviour, Reticle checks each change inside the running app, from network, state and console, while your coding agent works. Many teams run a review bot and a verifier together.
What is Greptile TREX?
Greptile TREX is an end-to-end testing agent that runs on pull requests. It works out which user flows a PR affects, starts the app in a sandbox built from your environment, uses it like a person, and posts pass or fail with logs, screenshots, traces and video. Each run costs 3 credits.
How is Reticle different from Greptile TREX?
Reticle is different from Greptile TREX in where it looks and when it runs. TREX watches the screen in a sandbox after a pull request opens. Reticle reads requests, application state and console from inside the app while your agent works, and replays saved flows deterministically with no model.
Does Reticle do code review?
No, Reticle does not do code review. It verifies what a change does when the app runs: the requests it sends, the state it changes and the console output, with the source line to fix on React and Svelte. For reviewing the diff itself, pair it with a code review tool.
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.