--- title: How to Fix Sitecore JSS Middleware Performance description: Learn how to troubleshoot and resolve Vercel Middleware timeouts and memory errors in your Sitecore JSS application caused by URLs with many query parameters. url: /kb/guide/how-to-fix-sitecore-jss-middleware-performance canonical_url: "https://vercel.com/kb/guide/how-to-fix-sitecore-jss-middleware-performance" published: 2025-11-03 last_updated: 2025-11-10 authors: Nick Vigier related: [] install_vercel_plugin: npx plugins add vercel/vercel-plugin --- ## Related pages > **For AI agents:** Follow these links to understand how this page connects to the rest of the Vercel ecosystem. For the full cross-link map (inbound, outbound, prerequisites, and semantic neighbors), see the .graph.md link below. - [Pricing & Usage](https://vercel.com/docs/manage-cdn-usage?from=related) — Understand CDN pricing resources, monitor usage from your dashboard, and optimize Fast Data Transfer, Fast Origin Transf - [Incremental Migration](https://vercel.com/docs/incremental-migration?from=related) — Learn how to migrate your app or website to Vercel with minimal risk and high impact. - [How to Optimize Next.js + Sitecore JSS](https://vercel.com/kb/guide/how-to-optimize-next.js-sitecore-jss?from=related) — This guide covers performance and usage considerations when building and deploying your Next.js and Sitecore JSS applica - [Troubleshooting Cross-Origin Errors \(net::ERR_BLOCKED_BY_ORB\) with Deployment Protection](https://vercel.com/kb/guide/troubleshooting-cross-origin-errors-neterr-blocked-by-orb-with-deployment-protection?from=related) — Learn to resolve \`net::ERR_BLOCKED_BY_ORB\` errors on protected Vercel deployments. This guide explains how cross-origi - [Troubleshooting Builds Failing with SIGKILL or Out of Memory Errors](https://vercel.com/kb/guide/troubleshooting-sigkill-out-of-memory-errors?from=related) — Learn how to troubleshoot builds failing with SIGKILL or Out of Memory errors on a Vercel Deployment. - [How to troubleshoot stale content returned from the Edge Network when using an external proxy or CDN](https://vercel.com/kb/guide/how-to-troubleshoot-stale-content-returned-from-the-edge-network-when-using-an-external-proxy-or-cdn?from=related) — Learn how to diagnose and fix stale content issues when using external proxies or CDNs with Vercel. Understand troublesh - [Troubleshooting Inconsistent Logs in Vercel Functions](https://vercel.com/kb/guide/troubleshooting-inconsistent-logs-in-vercel-functions?from=related) — Learn how to troubleshoot and resolve logs that appear mixed in Vercel Functions. This guide explains why logs from diff Full cross-link map for this page: [/kb/guide/how-to-fix-sitecore-jss-middleware-performance.graph.md](/kb/guide/how-to-fix-sitecore-jss-middleware-performance.graph.md) This guide addresses a specific issue where users of Sitecore JSS on Vercel experience `504: MIDDLEWARE_INVOCATION_TIMEOUT` or `500: JavaScript heap out of memory` errors when requests contain a large number of URL query parameters. Teams deploying Next.js applications with Sitecore JSS on Vercel may observe a pattern of request failures, specifically in the Edge Middleware. ## Symptoms - **Error Codes:** Function invocations fail with a `504: MIDDLEWARE_INVOCATION_TIMEOUT` status code or a `500` error referencing `JavaScript heap out of memory`. - **Trigger:** The errors are consistently triggered by accessing URLs that contain a large quantity of query string parameters. This is most common with URLs from marketing and ad campaigns, which often include numerous UTM parameters and tracking identifiers (e.g., `utm_source`, `utm_campaign`, `gclid`, `gbraid`). - **Behavior:** - Requests to the site's root domain or pages without query parameters succeed. - Requests with a small number of query parameters (e.g., 1-5) may also succeed. - As the number of parameters increases, the request either slows down dramatically or fails, crossing a threshold that triggers the timeout or memory limit. - **Impact:** This issue can significantly impact the effectiveness of paid marketing campaigns, as users clicking on sponsored links are unable to access the site, leading to a drop in tracked traffic and potential revenue loss. ## Root Cause Analysis Through investigation of multiple occurrences, this issue has been traced back to a specific performance problem within the Sitecore JSS for Next.js library. - **Affected Version:** The performance degradation is a known issue in **Sitecore JSS version** **`22.2.0`**. - **Technical Explanation:** The logic within the `@sitecore-jss/sitecore-jss-nextjs/middleware` package in version `22.2.0` is inefficient at processing and handling a large volume of `URLSearchParams`. This inefficiency leads to prolonged execution times and/or high memory consumption, eventually exceeding the platform's limits and causing the invocation to terminate. This is a code-level performance issue within the dependency, not a limitation of the Vercel platform. ## Troubleshooting and Verification Steps To confirm if your project is affected by this specific issue, follow these steps: 1. **Check Sitecore JSS Version:** Inspect your project's `package.json` file and look for the version of `@sitecore-jss/sitecore-jss-nextjs`. If the version is `22.2.0` or newer, but less than `22.6.0`, you are likely affected. 2. **Reproduce with Test Parameters:** Isolate the issue from specific campaign parameters by testing a URL with an increasing number of generic parameters. - **Test a working URL (few parameters):** `https://[your-domain]/?p1=1&p2=2&p3=3&p4=4&p5=5` - **Test a failing URL (many parameters):** `https://[your-domain]/?p1=1&p2=2&p3=3&p4=4&p5=5&p6=6&p7=7&p8=8` If the first URL loads and the second one times out, it strongly indicates that the quantity of parameters is the trigger. 3. **Review Function Logs:** Examine the logs for your Vercel project. Look for function invocations corresponding to the failing requests. You will see error messages confirming the timeout or out-of-memory error originating from your Edge Middleware. ## Solution and Workaround ### Permanent Solution The definitive solution is to upgrade the Sitecore JSS dependency in your project. - **Action:** Upgrade `@sitecore-jss/sitecore-jss-nextjs` to version **`22.6.0`** **or newer**. - **Reason:** Sitecore has officially addressed and resolved this performance issue in later releases of the library. Upgrading will replace the inefficient middleware logic with a more performant version that can handle a large number of query parameters without timing out. For detailed instructions on upgrading, consult the official Sitecore JSS documentation or contact Sitecore Support to ensure a smooth update process tailored to your specific implementation. ### Temporary Workaround If an immediate upgrade is not possible, you can mitigate the impact by reducing the number of query parameters used in your marketing campaigns. However, this is not a long-term solution and may limit your tracking capabilities. The recommended path is to upgrade the dependency.