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Catch the null-check before it ships

Mergegleam reviews every pull request the way your most careful senior engineer would, before it merges to main.

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@@ -42,7 +42,9 @@ async function getUser(req, res)

42 const user = await db.findUser(req.params.id);

43 - return res.json(user.profile);

44 + if (!user) return res.status(404).json({ error: 'Not found' });

45 + return res.json(user.profile);

46 }

Mergegleam Critical on line 43

db.findUser() can return null when no record matches. Accessing .profile on a null value throws at runtime. Guard required before access.

Mergegleam Warning on getUser

No test coverage for the 404 path. The new guard added here is untested. Consider adding a test case for a missing user ID.

4,200+ PRs reviewed

~8% catch rate on critical issues

< 90s avg review time

across early-access pilots

CI passes. The bug ships anyway.

Automated checks catch what you anticipated when you wrote them. The bugs that slip through are the ones nobody thought to test for.

Null pointer dereferences guarded by tests that never reach that path
Race conditions invisible to sequential unit tests
Regressions in code adjacent to the PR but not touched by it
Logic errors in conditional branches with low test coverage
Missing error handling on new API calls added under time pressure

lint: pass (0 errors)

tests: pass (247/247)

build: pass

merged to main

TypeError: Cannot read properties of null

Setup in minutes

One GitHub app. Every PR gets reviewed.

No configuration. No new workflow. Install the app and Mergegleam reviews every PR your team opens.

01 / install

Install the GitHub App

One click from the GitHub Marketplace. Select which repos to enable. No tokens to manage, no SSH keys.

02 / trigger

PR opened or updated

Mergegleam receives a webhook on every pull_request event: opened, synchronize, reopened.

03 / review

Review posted in seconds

Inline comments appear on the relevant diff lines. Reviewers see Mergegleam's findings alongside their own.

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What gets caught

What Mergegleam actually catches

Four categories of bugs that consistently escape CI, linters, and test suites, shown as real code.

null safety

Null and undefined dereference

When a function can return null and the caller doesn't check, Mergegleam flags the dereference even if tests never exercise that path.

test coverage

Missing test coverage for changed paths

New code paths added in the PR with no corresponding test coverage get flagged, so they don't silently merge untested.

regression

Regression in related untouched code

Mergegleam reads related functions that depend on what changed, catching regressions in code the PR author never touched.

logic

Logic error in conditional branch

Off-by-one errors, inverted conditions, and unreachable branches are caught by analyzing the logic rather than running the code.

Early access

From engineering teams using the early access

"Caught a null dereference in our billing path that had been in the codebase for three months. CI passed every time. Mergegleam flagged it on the first PR it reviewed."

Staff Engineer

logistics platform, early-access program

"We were skeptical about false positives. The signal quality is actually high: most comments are things a senior reviewer would have caught. Our on-call incidents dropped in the first month."

Engineering Lead

fintech team, early-access program

"The regression detection is the feature I didn't know I needed. It found a downstream break in code that wasn't in the diff. That's the bug that would have taken us a day to debug in prod."

Senior Backend Engineer

B2B SaaS team, early-access program

Pricing

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50 PR reviews / month
Null check and type error detection
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