--- title: Vercel Function Logs product: vercel url: /docs/functions/logs canonical_url: "https://vercel.com/docs/functions/logs" last_updated: 2026-08-11 type: reference prerequisites: - /docs/functions related: - /docs/drains - /docs/logs/runtime - /docs/functions/streaming-functions - /docs/incremental-static-regeneration - /docs/caching/cdn-cache summary: Use runtime logs to debug and monitor your Vercel Functions. install_vercel_plugin: npx plugins add vercel/vercel-plugin --- # Vercel Function Logs Vercel Functions allow you to debug and monitor your functions using runtime logs. Users on the Pro and Enterprise plans can use Vercel's support for [Log Drains](/docs/drains) to collect and analyze your logs using third-party providers. Functions have full support for the [`console`](https://developer.mozilla.org/docs/Web/API/Console) API, including `time`, `debug`, `timeEnd`, and more. ## 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. - [Add structured application logs to Vercel Functions](https://vercel.com/kb/guide/add-structured-application-logs-to-vercel-functions?from=related&source_path=%2Fdocs%2Ffunctions%2Flogs&source_site=vercel-docs&relationship=related) — Learn how to add structured application logs to Vercel Functions to help troubleshoot function issues in real time. - [How do I store logs on Vercel?](https://vercel.com/kb/guide/how-do-i-store-logs-on-vercel?from=related&source_path=%2Fdocs%2Ffunctions%2Flogs&source_site=vercel-docs&relationship=related) — Learn how to store logs on Vercel. - [Function streaming to be framework-agnostic on Vercel](https://vercel.com/blog/vercel-functions-streaming-to-be-framework-agnostic?from=related&source_path=%2Fdocs%2Ffunctions%2Flogs&source_site=vercel-docs&relationship=related) - [Troubleshooting Inconsistent Logs in Vercel Functions](https://vercel.com/kb/guide/troubleshooting-inconsistent-logs-in-vercel-functions?from=related&source_path=%2Fdocs%2Ffunctions%2Flogs&source_site=vercel-docs&relationship=related) — Learn how to troubleshoot and resolve logs that appear mixed in Vercel Functions. This guide explains why logs from diff - [Evolving Vercel Functions](https://vercel.com/blog/evolving-vercel-functions?from=related&source_path=%2Fdocs%2Ffunctions%2Flogs&source_site=vercel-docs&relationship=related) - [Enhanced Logs to search, inspect, and share runtime logs](https://vercel.com/changelog/enhanced-logs-ui-to-search-inspect-and-share-application-logs?from=related&source_path=%2Fdocs%2Ffunctions%2Flogs&source_site=vercel-docs&relationship=related) - [Runtime logs now show event sequences for Vercel requests](https://vercel.com/changelog/runtime-logs-now-show-event-sequences-for-vercel-requests?from=related&source_path=%2Fdocs%2Ffunctions%2Flogs&source_site=vercel-docs&relationship=related) - [Get logs for a deployment](https://vercel.com/docs/rest-api/logs/get-logs-for-a-deployment?from=related&source_path=%2Fdocs%2Ffunctions%2Flogs&source_site=vercel-docs&relationship=related) — GET /v1/projects/{projectId}/deployments/{deploymentId}/runtime-logs — Returns a stream of logs for a given deployment. - [Observability Insights](https://vercel.com/docs/observability/insights?from=related&source_path=%2Fdocs%2Ffunctions%2Flogs&source_site=vercel-docs&relationship=related) — List of available data sources that you can view and monitor with Observability on Vercel. - [Container Images](https://vercel.com/docs/functions/container-images?from=related&source_path=%2Fdocs%2Ffunctions%2Flogs&source_site=vercel-docs&relationship=related) — Deploy OCI container images with a Dockerfile or Containerfile on Vercel Functions. - [Vercel Documentation Sitemap](https://vercel.com/docs/sitemap.md?from=related&source_path=%2Fdocs%2Ffunctions%2Flogs&source_site=vercel-docs&relationship=related) — Browse Vercel documentation pages with summaries, prerequisites, and topics. Full cross-link map for this page: [/docs/functions/logs.graph.md](/docs/functions/logs.graph.md?from=related&source_path=%2Fdocs%2Ffunctions%2Flogs&source_site=vercel-docs&relationship=graph) ## Runtime Logs You can view [runtime logs](/docs/logs/runtime#what-are-runtime-logs) for all Vercel Functions in real-time from [the **Logs** section in the sidebar](/docs/logs/runtime#view-runtime-logs) of your project's dashboard. You can use the various filters and options to find specific log information. These logs are held for an [amount of time based on your plan](/docs/logs/runtime#limits). When your function is [streaming](/docs/functions/streaming-functions), you'll get the following: - You can [view the logs](/docs/logs/runtime#view-runtime-logs) in real-time from **Logs** in your dashboard sidebar. - Each action of writing to standard output, such as using `console.log`, results in a separate log entry. - Each of the logs are 256 KB **per line**. - The path in streaming logs will be prefixed with a forward slash (`/`). For more information, see [Runtime Logs](/docs/logs/runtime). > **💡 Note:** These changes in the frequency and format of logs will affect Log Drains. If > you are using Log Drains we recommend ensuring that your ingestion can handle > both the new format and frequency. ### Number of logs per request When a Function on a specific path receives a user request, you *may* see more than one log when the application renders or regenerates the page. This can occur in the following situations: 1. When a new page is rendered 2. When you are using [Incremental Static Regeneration (ISR)](/docs/incremental-static-regeneration) In the case of ISR, multiple logs are the result of: - A [stale](/docs/caching/cdn-cache#cache-invalidation) page having to be regenerated. For stale pages, both HTML (for direct browser navigation) and JSON (for Single Page App (SPA) transitions) are rendered simultaneously to maintain consistency - On-demand ISR happening with `fallback` set as [`blocking`](/docs/incremental-static-regeneration/quickstart). During on-demand ISR, the page synchronously renders (e.g., HTML) upon request, followed by a background revalidation of both HTML and JSON versions ### Next.js logs In Next.js projects, logged functions include API Routes (those defined in `pages/api/**/*.ts` or `app/**/route.ts`). Pages that use SSR, such as those that call `getServerSideProps` or export [`revalidate`](https://nextjs.org/docs/app/guides/incremental-static-regeneration), will also be available both in the filter dropdown and the real time logs. --- [View full sitemap](/docs/sitemap)