perch vs Amazon CodeWhisperer

Q Developer and Perch overlap only in "code quality," and even there they do different things. Q Developer is a generative assistant: real-time suggestions, inline chat, CLI autocompletion and natural-language-to-bash, agentic multi-step implementation with unit tests, Java 8-to-17 upgrades and .NET Windows-to-Linux porting, plus an AWS-expert chat in Slack, Teams, and the AWS Console. Its built-in security scanner finds vulnerabilities and proposes fixes. Perch doesn't generate or refactor code at all. It scans a tree with perch scan and reports rule ID, file:line, severity, a confidence percentage (e.g. 91%, 78%), and the enclosing method — probabilistic judgments, not pass/fail. Its differentiator is authoring: you write rules in perch.yaml with perch rules add --ensure in plain language, scope them with --each method/--each file and --where "src/**/*.ts", filter with --filter rule=<name>, test against a symbol with perch check <file>::<method>, and scan only changed files via --since origin/main. It catches off-by-one loops, MD5-hashed tokens, and unhandled nulls, fails CI on breaking findings with exit code 3, and stores results in .perch. Q Developer's checks are vendor-defined; Perch's are whatever your team commits.

Q Developer is freemium per its pricing data: there's a free tier plus a Pro tier whose stated benefit is that proprietary content isn't used for service improvement — relevant if your code can't train a vendor model. Specific dollar figures aren't in the data provided, so verify current AWS pricing before budgeting. Perch is free and open to install globally via npm (npm install -g @lakeday/perch), with findings stored locally in .perch. The honest cost of Perch isn't license fees — it's the engineering time to write and maintain your perch.yaml rules, since zero-config linting is explicitly not the product. If your team won't invest that authoring time, Perch delivers little; if it will, the marginal cost per scan is near zero. For Q Developer, the calculus flips: you get immediate value out of the box, but you're paying (or accepting the free tier's terms) and you're anchored to the AWS ecosystem. Note the not-for lists: Q Developer isn't for multi-cloud or non-AWS teams; Perch isn't for teams needing a hosted dashboard or org-wide analytics.