---
name: Changelog
slug: fern-changelog
type: feed
source_url: https://buildwithfern.com/learn/docs/changelog
organization: Fern
organization_slug: fern
total_releases: 89
latest_date: 2026-05-28
last_updated: 2026-06-04
tracking_since: 2024-01-24
canonical: https://releases.sh/fern/fern-changelog
organization_url: https://releases.sh/fern
---

<Release date="May 28, 2026" published="2026-05-28T00:00:00.000Z" url="https://buildwithfern.com/learn/docs/changelog/2026/5/28">
## May 28, 2026

## Scope search by product or version

You can now control how search results are ranked and filtered for sites with multiple products or versions using the new `settings.search` object in `docs.yml`.

- `prioritize-current-product` boosts results from the current product higher in the ranking without hiding other products.
- `default-filter-by-current-product` auto-selects the current product as a facet filter so only current-product results appear by default.

These options can be used independently or together.
</Release>

<Release date="May 19, 2026" published="2026-05-19T00:00:00.000Z" url="https://buildwithfern.com/learn/docs/changelog/2026/5/19">
## May 19, 2026

## Markdown rendering for API components

Interactive API components now render as fenced code blocks and structured content in your site's Markdown output. AI agents consuming your docs via `.md` URLs, `llms.txt`, or `llms-full.txt` receive the full request and response examples without parsing HTML, reducing content disparity between the rendered page and its Markdown representation.

This applies to the following components:

- [`<EndpointRequestSnippet>`](/learn/docs/writing-content/components/request-snippet)
- [`<EndpointResponseSnippet>`](/learn/docs/writing-content/components/response-snippet)
- [`<EndpointSchemaSnippet>`](/learn/docs/writing-content/components/endpoint-schema-snippet)
- [`<RunnableEndpoint>`](/learn/docs/writing-content/components/runnable-endpoint)
- [`<WebhookPayloadSnippet>`](/learn/docs/writing-content/components/webhook-payload-snippet)
- [`<Schema>`](/learn/docs/writing-content/components/schema)
- [`<SchemaSnippet>`](/learn/docs/writing-content/components/schema-snippet)
</Release>

<Release date="May 14, 2026" published="2026-05-14T00:00:00.000Z" url="https://buildwithfern.com/learn/docs/changelog/2026/5/14">
## May 14, 2026

## CLI link checker

You can now check for broken links on your live documentation site directly from the Fern CLI with `fern docs link check`. The command scrapes every page on your published site, checks all internal and external links, and reports broken (404) and blocked (403) URLs along with the source pages where they appear.

```bash
fern docs link check --url https://buildwithfern.com/learn
fern docs link check --url https://elevenlabs.io/docs
```

This complements the existing [`broken-links` rule](/learn/docs/configuration/site-level-settings#check-configuration) in `fern check`, which validates internal links against your local YAML navigation tree. Use `fern docs link check` after publishing to catch live 404s and broken external URLs that local validation can't detect.
</Release>

<Release date="May 4, 2026" published="2026-05-04T00:00:00.000Z" url="https://buildwithfern.com/learn/docs/changelog/2026/5/4">
## May 4, 2026

## Custom robots.txt

You can now serve your own [`robots.txt`](/learn/docs/seo/robots-txt) at the root of your documentation site by pointing `agents.robots-txt` at a file in your repo. Use this to opt in or out of specific AI crawlers like `GPTBot` or `ClaudeBot`, gate sensitive sections from indexing, or signal training and search preferences with the [Cloudflare Content Signals Policy](https://blog.cloudflare.com/content-signals-policy/). Your file is served verbatim at `/robots.txt`, and Fern appends a managed block disallowing internal API routes after your content.

```yaml
agents:
  robots-txt: ./robots.txt
```

## Multi-source docs

Multi-source docs lets each team publish independently to a shared custom domain — for example, [docs.nvidia.com](https://docs.nvidia.com) spans sub-paths like `/nvcf`, `/brev`, and `/aiperf`, each owned by a different product team and repository.

Set `multi-source: true` on the instance and reference a [global theme](/learn/docs/customization/global-themes) for consistent branding across repositories.

```yaml
global-theme: my-org-theme

instances:
  - url: example.docs.buildwithfern.com/product-a
    custom-domain: docs.example.com/product-a
    multi-source: true
```
</Release>

<Release date="May 1, 2026" published="2026-05-01T00:00:00.000Z" url="https://buildwithfern.com/learn/docs/changelog/2026/5/1">
## May 1, 2026

## API catalog discovery

AI agents, MCP clients, and API catalog crawlers can now discover your APIs automatically. Every Fern Docs site exposes a standards-based ([RFC 9727](https://www.rfc-editor.org/rfc/rfc9727)) `/.well-known/api-catalog` endpoint generated from your visible API Reference navigation.

## Custom URL actions on the Prompt component

You can now point `<Prompt>` actions at any AI tool, not just Cursor, Claude, and ChatGPT. Send readers to Perplexity, your own internal AI assistant, or any other URL.

```jsx
<Prompt
  title="Generate a TypeScript SDK"
  actions={[
    { label: "Open in Perplexity", url: "https://www.perplexity.ai/search?q={prompt}", icon: "magnifying-glass" },
    "cursor"
  ]}
>
Generate a TypeScript SDK from my OpenAPI spec. Follow the [TypeScript SDK quickstart](https://buildwithfern.com/learn/sdks/generators/typescript/quickstart.md).
</Prompt>
```
</Release>

<Release date="April 29, 2026" published="2026-04-29T00:00:00.000Z" url="https://buildwithfern.com/learn/docs/changelog/2026/4/29">
## April 29, 2026

## Redesigned dynamic OG images

Dynamic OG images have a new layout with fine-grained control over the logo variant, text and background colors, and which elements appear (section, description, URL, gradient).

```yaml
metadata:
  og:dynamic: true
  og:dynamic:background-image: ./images/og-background.png
  og:dynamic:text-color: "#1a1a1a"
  og:dynamic:background-color: "#ffffff"
  og:dynamic:logo-color: dark
  og:dynamic:show-logo: true
  og:dynamic:show-section: true
  og:dynamic:show-description: true
  og:dynamic:show-url: true
  og:dynamic:show-gradient: true
```
</Release>

<Release date="April 27, 2026" published="2026-04-27T00:00:00.000Z" url="https://buildwithfern.com/learn/docs/changelog/2026/4/27">
## April 27, 2026

## Prompt component

The `<Prompt>` component displays an AI prompt card with a title, icon, copy button, and optional "Open in" action buttons. Add it to any page so readers can copy instructions or open them directly in Cursor, Claude, or ChatGPT.

Use it in tutorials, quickstarts, migration guides, or any page where you want readers to hand off a task to an AI assistant — for example, scaffolding a project, generating an SDK, or applying a code change.

```jsx
<Prompt
  title="Create a docs site"
  icon="rocket"
  actions={["cursor", "claude", "chatgpt"]}
>
You are a **docs setup assistant**. Help the user create and publish a new docs site.

Follow the [Quickstart guide](https://buildwithfern.com/learn/docs/getting-started/quickstart) step by step.
</Prompt>
```

## Global themes

Define your documentation branding in a single control repository and share it across multiple sites. Use the `fern docs theme` CLI commands to export, upload, and manage themes, then reference a theme by name in any child repository's `docs.yml` with the `global-theme` property.
</Release>

<Release date="April 24, 2026" published="2026-04-24T00:00:00.000Z" url="https://buildwithfern.com/learn/docs/changelog/2026/4/24">
## April 24, 2026

## "Connect to Claude Code" page action

Fern Docs sites with [Ask Fern](/learn/docs/ai-features/ask-fern/overview) enabled now display a "Connect to Claude Code" button alongside existing page actions. Clicking the button copies a `claude mcp add` command. Readers can paste it into their terminal to register your site's [MCP server](/learn/docs/ai-features/mcp-server) with Claude Code.

The action is enabled by default and can be toggled off with `page-actions.options.claude-code: false` in `docs.yml`.
</Release>

<Release date="April 23, 2026" published="2026-04-23T00:00:00.000Z" url="https://buildwithfern.com/learn/docs/changelog/2026/4/23">
## April 23, 2026

## Clean up GitHub Actions preview deployments on merge

The [GitHub Actions preview workflow](/learn/docs/preview-publish/preview-changes#automate-with-github-actions) now has an optional companion `cleanup-preview.yml` workflow that deletes a pull request's preview deployment once the PR merges, so stale previews don't linger.

To adopt this workflow, add `.github/workflows/cleanup-preview.yml` alongside your existing preview workflow.
</Release>

<Release date="April 22, 2026" published="2026-04-22T00:00:00.000Z" url="https://buildwithfern.com/learn/docs/changelog/2026/4/22">
## April 22, 2026

## Clean up GitLab preview deployments on merge

The updated [GitLab CI/CD pipeline](/learn/docs/developer-tools/git-lab#add-the-cicd-pipeline) now includes a `cleanup_preview` stage that deletes a merge request's preview deployment once the MR merges into the default branch, so stale previews don't linger.

To adopt this workflow, replace your `.gitlab-ci.yml` file with the updated version.
</Release>

<Release date="April 21, 2026" published="2026-04-21T00:00:00.000Z" url="https://buildwithfern.com/learn/docs/changelog/2026/4/21">
## April 21, 2026

## Target the logo from custom scripts

`<Fern.Logo />` now renders with a `data-fern-logo` attribute so custom scripts can target the logo with `document.querySelector('#fern-header [data-fern-logo]')`. Use this to rewrite the logo's `href` on certain pages or modify other behavior.
</Release>

<Release date="April 20, 2026" published="2026-04-20T00:00:00.000Z" url="https://buildwithfern.com/learn/docs/changelog/2026/4/20">
## April 20, 2026

## Mobile table of contents bar

Pages using the [`guide` and `overview` layouts](/learn/docs/configuration/page-level-settings#layout) can now display a sticky table of contents bar below the header on mobile and tablet viewports. The bar shows a scroll progress indicator and the current heading, and expands to the full table of contents when tapped.

Enable it by adding `mobile-toc: true` under `layout` in `docs.yml`:

```yaml
layout:
  mobile-toc: true
```
</Release>

<Release date="April 14, 2026" published="2026-04-14T00:00:00.000Z" url="https://buildwithfern.com/learn/docs/changelog/2026/4/14">
## April 14, 2026

## AI search model update

Ask Fern now uses [Claude 4.6 Sonnet](https://www.anthropic.com/news/claude-sonnet-4-6) and [Claude 4.5 Haiku](https://www.anthropic.com/news/claude-haiku-4-5).

## Link to API Reference sections with `api:` syntax

The `api:` link syntax now supports linking to the root of an API Reference section. Use `api:apiName` to create a link that resolves to the landing page of a specific API Reference at build time. This is useful when your project has multiple APIs.

```mdx
Explore the [Plant Store API](api:plant-store) reference.
```
</Release>

<Release date="April 11, 2026" published="2026-04-11T00:00:00.000Z" url="https://buildwithfern.com/learn/docs/changelog/2026/4/11">
## April 11, 2026

## AsyncAPI spec endpoints

Fern docs sites serve your raw AsyncAPI 2.6.0 specification at `/asyncapi.json` and `/asyncapi.yaml` for sites with WebSocket channels. Download it for client generation, contract testing, or importing into AsyncAPI-compatible tools. The spec is also linked from your site's `llms.txt`, so AI coding assistants can discover and use it automatically.
</Release>

<Release date="April 10, 2026" published="2026-04-10T00:00:00.000Z" url="https://buildwithfern.com/learn/docs/changelog/2026/4/10">
## April 10, 2026

## Custom `llms.txt` and `llms-full.txt` files

Provide your own `llms.txt` and `llms-full.txt` files instead of using the auto-generated versions. Add paths to your files under the `agents` key in `docs.yml`:

```yaml
agents:
  llms-txt: ./path/to/llms.txt
  llms-full-txt: ./path/to/llms-full.txt
```

Custom files are served at the root-level `/llms.txt` and `/llms-full.txt` endpoints. Nested paths continue to use auto-generated output.

Requires Fern CLI version `4.67.0` or later.
</Release>

<Release date="April 9, 2026" published="2026-04-09T00:00:00.000Z" url="https://buildwithfern.com/learn/docs/changelog/2026/4/9">
## April 9, 2026

## Default per-page directive for AI agents

Every page served to AI agents now includes a default directive that tells agents how to navigate your documentation programmatically — pointing them to `.md` URLs, `llms.txt`, and `llms-full.txt`. The directive is automatically generated using your site's domain and basepath, so no configuration is needed.

```text
For clean Markdown of any page, append .md to the page URL. For a complete documentation index, see https://docs.example.com/llms.txt. For full documentation content, see https://docs.example.com/llms-full.txt.
```

You can still override the default with a custom directive or disable it entirely.

## Standalone search widget

Embed Ask Fern's AI-powered search on any React site using the [`@fern-api/search-widget`](https://www.npmjs.com/package/@fern-api/search-widget) package. The widget renders a button that opens a search modal connected to your documentation content. It requires React 19; all other dependencies are bundled.
</Release>

<Release date="April 2, 2026" published="2026-04-02T00:00:00.000Z" url="https://buildwithfern.com/learn/docs/changelog/2026/4/2">
## April 2, 2026

## Per-page directives in llms.txt

You can add a directive that's automatically prepended to every page when it's served to AI agents — both individual Markdown page URLs and each page section within `llms-full.txt`. The directive is only visible to agents requesting Markdown; human-facing documentation is unaffected.

```yaml
agents:
  page-directive: "For a complete page index, fetch https://docs.example.com/llms.txt"
```

## Missing redirects check rule

The `missing-redirects` rule for `fern check` detects pages that were removed or moved without a redirect. It compares your current docs navigation against the previously published state and warns when a previously published URL would return a 404.

```bash
[warning] Page "products/api-def/openapi/extensions/default.mdx" was removed. The previously published URL "/learn/api-definitions/openapi/extensions/default-values" will return 404 without a redirect. Consider adding a redirect in docs.yml to preserve existing links.
```

Configure its severity in `docs.yml`:

```yaml
check:
  rules:
    missing-redirects: error
```

## Library docs generator

Generate MDX documentation pages from your Python or C++ library source code and include them in your Fern Docs site. Configure your libraries in `docs.yml`, run `fern docs md generate`, and the generated pages appear as navigation sections alongside your other documentation.
</Release>

<Release date="March 31, 2026" published="2026-03-31T00:00:00.000Z" url="https://buildwithfern.com/learn/docs/changelog/2026/3/31">
## March 31, 2026

## Configure `fern check` rule severity

You can now configure the severity of validation rules run by `fern check` directly in your `docs.yml` file using the `check.rules` property. Set individual rules to `"warn"` (non-blocking) or `"error"` (blocking) to control which checks fail your build.

```yaml
check:
  rules:
    broken-links: error
    example-validation: warn
```

The `--broken-links` and `--strict-broken-links` CLI flags are now deprecated in favor of this configuration.

## AI search upgrade

Ask Fern now runs on Claude 4.6 Sonnet for faster, more accurate answers.

## Context7 integration

Host a [Context7](https://context7.com/) verification file on your Fern docs site. Add `integrations.context7` to your `docs.yml` pointing to your `context7.json` file, and Fern serves it at `/context7.json` on your domain.

```yaml
integrations:
  context7: ./path/to/context7.json
```

Requires Fern CLI version `4.52.0` or later.
</Release>

<Release date="March 30, 2026" published="2026-03-30T00:00:00.000Z" url="https://buildwithfern.com/learn/docs/changelog/2026/3/30">
## March 30, 2026

## Tab alignment and placement options

You can now finetune how your tabs look and behave using `theme.tabs` in `docs.yml`. Choose between the default underline or bubble style, place tabs in the header or sidebar, and center-align header tabs from a single configuration block.

```yaml
theme:
  tabs:
    style: bubble
    alignment: center
    placement: header
```

The existing string shorthand (e.g., `theme.tabs: bubble`) continues to work for simple style changes.
</Release>

<Release date="March 27, 2026" published="2026-03-27T00:00:00.000Z" url="https://buildwithfern.com/learn/docs/changelog/2026/3/27">
## March 27, 2026

## Sitemap timestamps

Your sitemap entries now include a `<lastmod>` timestamp that's invisible to readers and used exclusively by search engines to prioritize crawling recently updated pages. Timestamps update only when a page's content actually changes — trivial formatting differences like whitespace or capitalization are ignored. This follows [Google's sitemap best practices](https://developers.google.com/search/docs/crawling-indexing/sitemaps/build-sitemap).
</Release>

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