See if emails are opened by sending tracking pixels. Receive open events via webhook or view which recipients opened an email in the [MailSlurp](/api/) dashboard. ## When open tracking is actually useful Open tracking is most useful when your team needs to answer one of these operational questions: - did a recipient engage with an onboarding, billing, or lifecycle message? - are campaigns or recurring streams getting opens after a template change? - should an automation or follow-up workflow trigger after an open event? - do we need extra evidence while troubleshooting message performance? Open tracking is not a replacement for sender monitoring or campaign QA. It works best alongside [Domain monitor](/lp/domain-monitor/), [Campaign Probe](/lp/campaign-probe/), and [Email deliverability](/product/email-deliverability/). ## Code example ```typescript import "jest"; import fetch from "node-fetch"; import { MailSlurp } from "mailslurp-client"; const timeout = 120000; const mailslurp = new MailSlurp({ apiKey: process.env.apiKey }); jest.setTimeout(timeout); describe("tracking controller", () => { it("can create a pixel and trigger seen", async () => { const pixel = await mailslurp.trackingController.createTrackingPixel({}); expect(pixel.seen).toEqual(false); const res = await fetch(pixel.url); expect(res.ok).toBeTruthy(); const pixel2 = await mailslurp.trackingController.getTrackingPixel(pixel.id); expect(pixel2.seen).toEqual(true); }); it("can send email with tracking", async () => { const inbox1 = await mailslurp.createInbox(); const inbox2 = await mailslurp.createInbox(); const sent = await mailslurp.inboxController.sendEmailAndConfirm(inbox1.id!, { to: [inbox2.emailAddress!], body: "Hello user", addTrackingPixel: true, }); expect(sent.pixelIds?.length).toEqual(1); const pixelId = sent.pixelIds?.[0]; const pixel = await mailslurp.trackingController.getTrackingPixel(pixelId!); expect(pixel.seen).toEqual(false); const res = await fetch(pixel.url); expect(res.ok).toBeTruthy(); const pixel2 = await mailslurp.trackingController.getTrackingPixel(pixel.id); expect(pixel2.seen).toEqual(true); }); }); ``` ## What to pair with tracking pixels Tracking pixels answer whether an open event happened. They do not answer every other reliability question around the message. - Use [Campaign Probe](/lp/campaign-probe/) when you also need broken-link, missing-image, and stream-level quality monitoring. - Use [Domain monitor](/lp/domain-monitor/) when the main risk is sender-auth drift. - Use [Email audit](/tools/email-audit/) when you need a one-shot pre-send review before launch. - Use [Email webhooks](/product/email-webhooks/) when open events should trigger downstream systems. ## Production rollout tips for tracking pixels Before using open tracking in production: - Verify template behavior across clients with [Email rendering tests](/lp/email-rendering-test/). - Validate sender posture and message reliability with [Email deliverability](/product/email-deliverability/). - Route open events into automation safely using [Email webhooks](/product/email-webhooks/). - Use [Email integration testing](/product/email-integration-testing/) to test event behavior in controlled environments.