diff --git a/app/api/unstable_validate/route.ts b/app/api/unstable_validate/route.ts
new file mode 100644
index 00000000..51e2900c
--- /dev/null
+++ b/app/api/unstable_validate/route.ts
@@ -0,0 +1,215 @@
+import { NextRequest, NextResponse } from "next/server";
+import { AtpAgent, AtUri } from "@atproto/api";
+import { DidResolver } from "@atproto/identity";
+import {
+  PubLeafletDocument,
+  PubLeafletPublication,
+  PubLeafletPagesLinearDocument,
+  PubLeafletPagesCanvas,
+} from "lexicons/api";
+
+const didResolver = new DidResolver({});
+
+export async function GET(request: NextRequest) {
+  try {
+    const atUriString = request.nextUrl.searchParams.get("uri");
+
+    if (!atUriString) {
+      return NextResponse.json(
+        {
+          success: false,
+          error: "Missing uri parameter",
+        },
+        { status: 400 },
+      );
+    }
+
+    const uri = new AtUri(atUriString);
+
+    // Only allow document and publication collections
+    if (
+      uri.collection !== "pub.leaflet.document" &&
+      uri.collection !== "pub.leaflet.publication"
+    ) {
+      return NextResponse.json(
+        {
+          success: false,
+          error:
+            "Unsupported collection type. Must be pub.leaflet.document or pub.leaflet.publication",
+        },
+        { status: 400 },
+      );
+    }
+
+    // Resolve DID to get service endpoint
+    const did = await didResolver.resolve(uri.host);
+    const service = did?.service?.[0];
+
+    if (!service) {
+      return NextResponse.json(
+        {
+          success: false,
+          error: "Could not resolve DID service endpoint",
+        },
+        { status: 404 },
+      );
+    }
+
+    // Fetch the record from AT Protocol
+    const agent = new AtpAgent({ service: service.serviceEndpoint as string });
+
+    let recordResponse;
+    try {
+      recordResponse = await agent.com.atproto.repo.getRecord({
+        repo: uri.host,
+        collection: uri.collection,
+        rkey: uri.rkey,
+      });
+    } catch (e) {
+      return NextResponse.json(
+        {
+          success: false,
+          error: "Record not found",
+        },
+        { status: 404 },
+      );
+    }
+
+    // Validate based on collection type
+    if (uri.collection === "pub.leaflet.document") {
+      const result = PubLeafletDocument.validateRecord(
+        recordResponse.data.value,
+      );
+      if (result.success) {
+        return NextResponse.json({
+          success: true,
+          collection: uri.collection,
+          record: result.value,
+        });
+      } else {
+        // Detailed validation: validate pages and blocks individually
+        const record = recordResponse.data.value as {
+          pages?: Array<{ $type?: string; blocks?: Array<{ block?: unknown }> }>;
+        };
+        const pageErrors: Array<{
+          pageIndex: number;
+          pageType: string;
+          error?: unknown;
+          blockErrors?: Array<{
+            blockIndex: number;
+            blockType: string;
+            error: unknown;
+            block: unknown;
+          }>;
+        }> = [];
+
+        if (record.pages && Array.isArray(record.pages)) {
+          for (let pageIndex = 0; pageIndex < record.pages.length; pageIndex++) {
+            const page = record.pages[pageIndex];
+            const pageType = page?.$type || "unknown";
+
+            // Validate page based on type
+            let pageResult;
+            if (pageType === "pub.leaflet.pages.linearDocument") {
+              pageResult = PubLeafletPagesLinearDocument.validateMain(page);
+            } else if (pageType === "pub.leaflet.pages.canvas") {
+              pageResult = PubLeafletPagesCanvas.validateMain(page);
+            } else {
+              pageErrors.push({
+                pageIndex,
+                pageType,
+                error: `Unknown page type: ${pageType}`,
+              });
+              continue;
+            }
+
+            if (!pageResult.success) {
+              // Page has errors, validate individual blocks
+              const blockErrors: Array<{
+                blockIndex: number;
+                blockType: string;
+                error: unknown;
+                block: unknown;
+              }> = [];
+
+              if (page.blocks && Array.isArray(page.blocks)) {
+                for (
+                  let blockIndex = 0;
+                  blockIndex < page.blocks.length;
+                  blockIndex++
+                ) {
+                  const blockWrapper = page.blocks[blockIndex];
+                  const blockType =
+                    (blockWrapper?.block as { $type?: string })?.$type ||
+                    "unknown";
+
+                  // Validate block wrapper based on page type
+                  let blockResult;
+                  if (pageType === "pub.leaflet.pages.linearDocument") {
+                    blockResult =
+                      PubLeafletPagesLinearDocument.validateBlock(blockWrapper);
+                  } else {
+                    blockResult =
+                      PubLeafletPagesCanvas.validateBlock(blockWrapper);
+                  }
+
+                  if (!blockResult.success) {
+                    blockErrors.push({
+                      blockIndex,
+                      blockType,
+                      error: blockResult.error,
+                      block: blockWrapper,
+                    });
+                  }
+                }
+              }
+
+              pageErrors.push({
+                pageIndex,
+                pageType,
+                error: pageResult.error,
+                blockErrors: blockErrors.length > 0 ? blockErrors : undefined,
+              });
+            }
+          }
+        }
+
+        return NextResponse.json({
+          success: false,
+          collection: uri.collection,
+          error: result.error,
+          pageErrors: pageErrors.length > 0 ? pageErrors : undefined,
+          record: recordResponse.data.value,
+        });
+      }
+    }
+
+    if (uri.collection === "pub.leaflet.publication") {
+      const result = PubLeafletPublication.validateRecord(
+        recordResponse.data.value,
+      );
+      if (result.success) {
+        return NextResponse.json({
+          success: true,
+          collection: uri.collection,
+          record: result.value,
+        });
+      } else {
+        return NextResponse.json({
+          success: false,
+          collection: uri.collection,
+          error: result.error,
+        });
+      }
+    }
+  } catch (error) {
+    console.error("Error validating AT URI:", error);
+    return NextResponse.json(
+      {
+        success: false,
+        error: "Invalid URI or internal error",
+      },
+      { status: 400 },
+    );
+  }
+}