--- title: "Tools to help build and check my website · Proxy Mail QA" description: "A toolkit for checking a website while you build it and after it goes live: speed, accessibility, SEO, links, security, devices and email." url: https://proxymail.qa/solve/tools-to-help-build-and-check-my-website --- 1. [Home](https://proxymail.qa/) 2. [What we solve](https://proxymail.qa/solve) # Tools to help build and check my website A website is checked in two places: while you build it, so mistakes don't get in, and before and after it goes live, so the ones that did get found. Here's a toolkit for both, by area. Updated 5 November 2026 > **Our recommendation, up front.** We make Proxy Mail QA, so we’re not neutral, and it covers only one row of this toolkit: checking your sign-up, log-in and account emails. Speed, accessibility, SEO, broken links, security and how the site looks on different devices all need other tools, most of them free. We name them below; none of them are ours. ## While you build | Tool | What it catches | | ------------------------------------------------------- | -------------------------------------------------------------------------------- | | A type checker (TypeScript) | Wrong data in the wrong place, before you run anything | | A linter (ESLint) and a formatter (Prettier) | Common mistakes and inconsistent code | | Your browser’s DevTools | Errors in the console, failed requests in the Network tab, layout in device mode | | Preview deployments (Vercel, Netlify, Cloudflare Pages) | A link for every change, so it’s checked on a real server before it’s merged | | An AI coding agent (Qoder, Claude Code, Cursor) | A second read of each change, and running the checks below for you | ## Before and after it goes live | Area | What to check | Tools | | ---------------------------------- | ---------------------------------------------------------------------------------- | -------------------------------------------------------------------------------------------------------------------------------------- | | Speed | Load time on a phone, layout shifts, image sizes | Lighthouse (in Chrome DevTools), PageSpeed Insights (which adds real visitors’ data once you have traffic), WebPageTest | | Accessibility | Labels, contrast, headings, keyboard use, screen readers | axe DevTools, WAVE, Lighthouse; then the keyboard alone and a screen reader (VoiceOver, NVDA). Automated tools find only some problems | | HTML and links | Invalid markup, broken links, missing pages | The W3C Markup Validation Service, the W3C Link Checker, or a crawler such as Screaming Frog | | Devices and browsers | Layout on small screens, Safari and Firefox differences | DevTools device mode, a real phone, BrowserStack or LambdaTest for devices you don’t have | | SEO | Pages indexed, titles and descriptions, structured data | Google Search Console, Bing Webmaster Tools, Lighthouse’s SEO audit, Google’s Rich Results Test | | Security basics | HTTPS set up properly, security headers, known-vulnerable packages | Qualys SSL Labs, Security Headers, npm audit or Dependabot, ZAP (formerly OWASP ZAP) against your own staging site | | Sign-up, log-in and account emails | The email arrives, its code or link works, it’s sent properly, exactly one arrives | **Proxy Mail QA**. For seeing emails during local development only, Mailpit | | Whole flows | Sign-up, checkout and other journeys still work after a change | Playwright or Cypress | | After launch | The site is up, errors are seen, people find what they need | An uptime monitor (UptimeRobot, Better Stack), Sentry, your analytics | ## What Proxy Mail QA checks, and what it doesn’t **It checks** the parts of your site that depend on an email: - A new private test address for every try, so a test never picks up an old code. - The verification code or sign-in, invite or reset link, pulled out of the email. - How the email was sent: SPF, DKIM and DMARC, links to `localhost` or plain `http`, where the link goes, whether it says when it expires, and a plain-text part. - That exactly one email arrived, or that none did. - Unusual addresses, names and passwords to try in the form, so you can see how it handles them. You can use it by hand with [Proxy Mail QA for Chrome](https://proxymail.qa/chrome-extension), in Playwright or Cypress through its npm package, or from an AI agent through its MCP server. **It doesn’t check** design, wording, speed, accessibility, SEO or security, and it doesn’t receive SMS. ## Let an agent run the checks An AI agent such as Qoder’s can run most of this toolkit for you on a preview deployment: Lighthouse from the command line, a link checker, your Playwright tests, and, with Proxy Mail QA connected from the [Qoder Marketplace](https://qoder.com/en/marketplace/connector?id=proxymail-qa), the sign-up email. A prompt to start from: Prompt ```text Check the preview at https://acme-git-new-pricing.vercel.app before I merge. 1. Run Lighthouse for the home page and the sign-up page, on mobile. List anything under 90, with the biggest fixes first. 2. Run a link check over the site and list broken links. 3. Sign up with a new Proxy Mail QA address, finish the verification, and run check_email with expect_host set to the preview's host. count_emails should be 1. 4. Give me one list of what to fix, most important first. ``` Still look at the site yourself, on a phone, before it goes live. No tool tells you whether it’s clear. For a step-by-step review of a whole site, see [Help me check my website](https://proxymail.qa/solve/help-me-check-my-website). ## Try it on your next sign-up test Free plan, no credit card. Create an address and watch the code or link arrive. [Create a free account](https://app.proxymail.qa/?mode=signup&from=site-solve-tools-to-help-build-and-check) ## Related guides - [Test sign-up and email verificationA fresh, private address for every sign-up test, with the verification link or code ready the moment it lands.](https://proxymail.qa/solve/email-verification-testing) - [Test OTP and one-time login codesCodes pulled out of the email with a Copy button and a countdown when the email says how long they last.](https://proxymail.qa/solve/otp-code-testing) - [Test magic links and passwordless sign-inSingle-use links that are never opened or prefetched on our side, so they still work when you click them.](https://proxymail.qa/solve/magic-link-testing) - [Test password reset emailsRequest, receive and use reset links, and keep the new password saved next to the test account.](https://proxymail.qa/solve/password-reset-testing) - [Stop sharing one Gmail inbox for QAPrivate, disposable addresses for every tester instead of one shared mailbox and a pile of plus-addresses.](https://proxymail.qa/solve/shared-test-inbox) - [Take QA notes by voice with Wispr FlowDictate what each test account is for, its state and what you found, straight into its notes, in seconds.](https://proxymail.qa/solve/voice-notes-wispr-flow) - [Verification link points to localhost:3000Why emails from staging link to localhost, how to fix it in Supabase, Firebase and other stacks, and how we flag it.](https://proxymail.qa/solve/localhost-links) - [Common Supabase sign-up and login problemsEmails that never arrive, links that expire or sign nobody in, and sign-ups that fail, with the fix for each.](https://proxymail.qa/solve/supabase-auth-problems) - [Common Firebase sign-up and login problemsMissing verification and reset emails, verified users who still look unverified, failing links and sign-up limits, with the fix for each.](https://proxymail.qa/solve/firebase-auth-problems) - [Sign-up and login problems in vibe-coded appsThe login bugs AI-built apps usually ship with: emails only you receive, links to the preview, missing pages, and what to ask the builder.](https://proxymail.qa/solve/vibe-coded-login-problems) - [Test sign-up emails in PlaywrightA complete Playwright test for sign-up codes and links, from a fresh inbox to the report on the pull request.](https://proxymail.qa/solve/playwright-email-tests) - [Test sign-up emails in CypressA complete Cypress test for sign-up links and codes, with the email waits running as Cypress tasks.](https://proxymail.qa/solve/cypress-email-tests) - [Test sign-up emails with pytestA complete pytest test for sign-up codes and links, with Playwright for Python or Selenium and a one-file helper.](https://proxymail.qa/solve/pytest-email-tests) - [Test coupon codes and welcome offersThe coupon with its discount, end date and arrival time, what checkout did with it, and a failure when an expired or reused one is accepted.](https://proxymail.qa/solve/coupon-code-testing) - [Test unsubscribe links and one-click unsubscribeThe unsubscribe headers and link checked on every marketing email, and a watch that flags any marketing after unsubscribing, with no time limit.](https://proxymail.qa/solve/unsubscribe-testing) - [Test that a welcome offer can't be claimed twiceVersions of one address that reach the same inbox, and a check that fails when the same person got the offer more than once.](https://proxymail.qa/solve/welcome-offer-abuse) - [AI sign-up page reviewLet an agent check the sign-up through to the email: delivery, the link, how it was sent, and that only one arrives.](https://proxymail.qa/solve/ai-sign-up-page-review) - [AI registration page reviewAn agent tries every field with values made for it, then finishes the registration through the email.](https://proxymail.qa/solve/ai-registration-page-review) - [Review a sign-up page by handA checklist for your browser and phone, in the order that finds the most problems.](https://proxymail.qa/solve/how-to-review-my-sign-up-page) - [Review a simple sign-up form12 checks for a form with an email, a password and perhaps a name.](https://proxymail.qa/solve/review-a-simple-sign-up-form) - [Review a multi-page sign-up formOne test account across every screen, and the verification email wherever it comes.](https://proxymail.qa/solve/review-a-multi-page-sign-up-form) - [Review a financial sign-up formThe emails, age and country rules and awkward values in a financial sign-up, and what needs other tools.](https://proxymail.qa/solve/review-a-financial-website-sign-up-form) - [An email address for testing registrationA new, real address for every registration try, with the code or link ready to use.](https://proxymail.qa/solve/email-for-checking-my-registration-form) - [An email address for testing sign-inTest accounts with saved passwords and an inbox for codes, magic links and resets.](https://proxymail.qa/solve/email-for-checking-my-sign-in-form) - [How long should a password be?NIST's numbers for password length and rules, and test passwords to check yours.](https://proxymail.qa/solve/how-long-should-my-registration-form-password-be) - [No error for a password that breaks the rulesThe eight usual causes of a silent password field, and how to tell which one it is.](https://proxymail.qa/solve/why-is-my-registration-form-not-showing-password-errors) - [Help me check my websiteA whole-site check in an afternoon, in the order that finds the costliest problems first.](https://proxymail.qa/solve/help-me-check-my-website) - [What tools do I need for a website?The full list, then which parts a simple site can skip.](https://proxymail.qa/solve/what-tools-do-i-need-when-building-a-website) [Built your app with an AI tool? Pick yours](https://proxymail.qa/built-with)