---
title: "Notion API Oversized page edits return HTTP 400: 2026-10-02 | Harbyn"
description: "Notion API Oversized page edits return HTTP 400, announced Oct 2, 2026."
canonical: "https://harbyn.com/changes/notion/2026-10-02-page-edits-return-400-when-a-page-is-too-large-to-load"
last-updated: 2026-10-09
---

# Notion API Oversized page edits return HTTP 400

Markdown version of <https://harbyn.com/changes/notion/2026-10-02-page-edits-return-400-when-a-page-is-too-large-to-load>.

Behavior change - Notion API. low severity. In effect.

Updating a page's content as markdown or using the notion-update-page MCP tool now returns HTTP 400 validation\_error when the page is too large to load in full (about 20,000 records) and the edit targets an unloaded block or would remove unloaded content. Previously, these requests returned HTTP 500 internal\_server\_error. The response includes additional\_data.limit\_kind set to page\_record\_count and additional\_data.limit with the limit value.

## Facts

| Fact | Value |
| --- | --- |
| Vendor | [Notion API](https://harbyn.com/vendors/notion.md) |
| Kind | Behavior change |
| Severity | low |
| Status | In effect |
| Announced | Oct 2, 2026 |
| Added to Harbyn | Oct 9, 2026 |
| Lead time | No dated deadline |
| Symbols | `notion-update-page` |
| Review | Reviewed by a person, extracted by a model |

## Find it in your code

```sh
npx harbyn scan
```

This change names no identifier the scanner can match line by line, so the scan tells you whether your repository uses Notion API, from its packages and API hosts. Nothing leaves your machine.

## Sources

Where this event comes from: the page we read, when we read it, and the hash of that snapshot.

- <https://developers.notion.com/page/changelog.md> (changelog, fetched 2026-10-09 22:43 UTC, sha256 `8f3c696a723214ca515d6c00b32daa5e67091eb0a87f1ee6fb7958347e10b5c5`)

## Related changes

### More from Notion API

- [Markdown content API and Notion MCP return custom blocks instead of unknown elements](https://harbyn.com/changes/notion/2026-09-30-custom-blocks-in-markdown.md) (Behavior change, announced Sep 30, 2026)
- [Completing the query tool update in Notion MCP](https://harbyn.com/changes/notion/2026-09-29-completing-the-query-tool-update-in-notion-mcp.md) (Retirement, effective Sep 29, 2026)
- [notion-fetch no longer signs file URLs by default](https://harbyn.com/changes/notion/2026-10-05-notion-fetch-no-longer-signs-file-urls-by-default.md) (Breaking change, announced Oct 5, 2026)
- [notion-get-tool-access is optional](https://harbyn.com/changes/notion/2026-10-07-notion-get-tool-access-is-optional.md) (Behavior change, announced Oct 7, 2026)

### Changes at other vendors

- [Amazon Selling Partner API: ORDER\_CHANGE notifications add PreFulfillmentStatusChange for Amazon Autos](https://harbyn.com/changes/amazon-sp-api/2026-10-14-sp-api-updates-new-listings-items-api-ivp-values-in-eu5-jp-and-ca-stores-oct-3.md) (effective Oct 28, 2026)
- [BigCommerce: 301 redirects will apply only to storefront channels](https://harbyn.com/changes/bigcommerce/2026-10-07-301-redirects-now-apply-to-storefront-channels-only.md) (effective Nov 10, 2026)
- [GitHub: Secret scanning audit log business field changes to enterprise slug](https://harbyn.com/changes/github/2026-10-20-updates-to-github-secret-scanning-7.md) (effective Nov 12, 2026)
- [Jira / Atlassian Cloud: New IP address ranges in use from January 1, 2027](https://harbyn.com/changes/atlassian-jira/2026-10-16-atlassian-cloud-adds-new-ip-address-ranges.md) (effective Jan 1, 2027)

[All upcoming deadlines](https://harbyn.com/deadlines.md)