diff --git a/package.json b/package.json
index 971cc82c..652d52bc 100644
--- a/package.json
+++ b/package.json
@@ -86,5 +86,8 @@
     "typescript": "^5.9.2",
     "vitest": "^3.1.4"
   },
+  "optionalDependencies": {
+    "@seonbi/node": "0.2.2"
+  },
   "packageManager": "pnpm@9.15.1+sha512.1acb565e6193efbebda772702950469150cf12bcc764262e7587e71d19dc98a423dff9536e57ea44c49bdf790ff694e83c27be5faa23d67e0c033b583be4bfcf"
 }
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index 269dd9df..56d7ce47 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -158,6 +158,10 @@ importers:
       zod:
         specifier: ^4.3.5
         version: 4.3.5
+    optionalDependencies:
+      '@seonbi/node':
+        specifier: 0.2.2
+        version: 0.2.2
     devDependencies:
       '@biomejs/biome':
         specifier: ^2.4.4
@@ -2191,6 +2195,39 @@ packages:
       '@opentelemetry/sdk-trace-base': ^1.30.1 || ^2.1.0
       '@opentelemetry/semantic-conventions': ^1.39.0
 
+  '@seonbi/node-darwin-arm64@0.2.2':
+    resolution: {integrity: sha512-seMwCWrP57tRU+K4q0UrpulUKW6Iydu6CZqOTqul+p/QhI9iQ3RR4yL374QXi3WI56KcwAFQ+gIfl1PWTVX4NA==}
+    cpu: [arm64]
+    os: [darwin]
+
+  '@seonbi/node-darwin-x64@0.2.2':
+    resolution: {integrity: sha512-ujSO6hJC8sJHQdUsn99sVFhlKhwnSr1QFOMWP+ZRy5knLvgX8vGMTTh3oTF8gajOD0BhhdMK5DEIQg31vSancA==}
+    cpu: [x64]
+    os: [darwin]
+
+  '@seonbi/node-linux-arm64-gnu@0.2.2':
+    resolution: {integrity: sha512-cPR+NPTXCr3nK/oOsm9vAA8cYZy7qwe/++qYgJ6L/5BvfyipOSesBaRIVhbBVuXFm6Y2IjRezhX+krIoMrwuxQ==}
+    cpu: [arm64]
+    os: [linux]
+
+  '@seonbi/node-linux-x64-gnu@0.2.2':
+    resolution: {integrity: sha512-LyLe7Jy7ltr0D5C7CKkP7mpUeBsWD1ffAnQhgz1IfQXVTxYYEgYRjKOVaCVGCXVE1SKJCis1cG6mEYCehfYpQw==}
+    cpu: [x64]
+    os: [linux]
+
+  '@seonbi/node-linux-x64-musl@0.2.2':
+    resolution: {integrity: sha512-gBIYQAB9g0SHvVJ1y9YAvZPGRYKSM6Ll0JG0cYz9VYY4WjjxUpWuqJac/K0fcEvSP46VLXU/WjUjBX74bBLK3A==}
+    cpu: [x64]
+    os: [linux]
+
+  '@seonbi/node-win32-x64-msvc@0.2.2':
+    resolution: {integrity: sha512-SHxLaMj/FUAJMmBY4a2oPeCD4uKQ2vKNSNdCCwY+/Q8nRVcPPqtui7owf+7/mJhu6SxXVSBqujOxsrlWvfVgWw==}
+    cpu: [x64]
+    os: [win32]
+
+  '@seonbi/node@0.2.2':
+    resolution: {integrity: sha512-FpsjHw71LUGrss7DwJXcePQPdN8UU4qZi5On67K/LFNYn8tRbdjbh4tlK1rKdx3BwS1m0GGNUMxwpdZ5Dwsi/Q==}
+
   '@shikijs/core@3.22.0':
     resolution: {integrity: sha512-iAlTtSDDbJiRpvgL5ugKEATDtHdUVkqgHDm/gbD2ZS9c88mx7G1zSYjjOxp5Qa0eaW0MAQosFRmJSk354PRoQA==}
 
@@ -7671,6 +7708,34 @@ snapshots:
       '@opentelemetry/semantic-conventions': 1.39.0
       '@sentry/core': 10.39.0
 
+  '@seonbi/node-darwin-arm64@0.2.2':
+    optional: true
+
+  '@seonbi/node-darwin-x64@0.2.2':
+    optional: true
+
+  '@seonbi/node-linux-arm64-gnu@0.2.2':
+    optional: true
+
+  '@seonbi/node-linux-x64-gnu@0.2.2':
+    optional: true
+
+  '@seonbi/node-linux-x64-musl@0.2.2':
+    optional: true
+
+  '@seonbi/node-win32-x64-msvc@0.2.2':
+    optional: true
+
+  '@seonbi/node@0.2.2':
+    optionalDependencies:
+      '@seonbi/node-darwin-arm64': 0.2.2
+      '@seonbi/node-darwin-x64': 0.2.2
+      '@seonbi/node-linux-arm64-gnu': 0.2.2
+      '@seonbi/node-linux-x64-gnu': 0.2.2
+      '@seonbi/node-linux-x64-musl': 0.2.2
+      '@seonbi/node-win32-x64-msvc': 0.2.2
+    optional: true
+
   '@shikijs/core@3.22.0':
     dependencies:
       '@shikijs/types': 3.22.0
diff --git a/src/text.ts b/src/text.ts
index da784624..2b82c43f 100644
--- a/src/text.ts
+++ b/src/text.ts
@@ -262,8 +262,106 @@ export function extractText(html: string | null): string | null {
   return $(":root").text();
 }
 
-// biome-ignore lint/complexity/useLiteralKeys: tsc claims about this
-const SEONBI_URL = process.env["SEONBI_URL"];
+export type PostContentTransformer = (html: string) => Promise<string>;
+
+const koPostContentTransformer = await determineKoPostContentTransformer();
+
+async function determineKoPostContentTransformer(): Promise<PostContentTransformer> {
+  const SEONBI_NATIVE =
+    process.env.SEONBI_NATIVE?.trim()?.toLowerCase() === "true";
+
+  // biome-ignore lint/complexity/useLiteralKeys: tsc claims about this
+  const SEONBI_URL = process.env["SEONBI_URL"];
+
+  const SEONBI_CONFIGURATION = {
+    contentType: "text/html",
+    quote: "HorizontalCornerBrackets",
+    cite: "AngleQuotes",
+    arrow: {
+      bidirArrow: true,
+      doubleArrow: true,
+    },
+    ellipsis: true,
+    emDash: true,
+    stop: "Horizontal",
+    hanja: {
+      rendering: "HanjaInRuby",
+      reading: {
+        initialSoundLaw: true,
+        useDictionaries: ["kr-stdict"],
+        dictionary: {},
+      },
+    },
+  } satisfies import("@seonbi/node").Configuration;
+
+  if (SEONBI_NATIVE) {
+    try {
+      const { transform } = await import("@seonbi/node");
+      return async (html: string) => {
+        try {
+          return transform(SEONBI_CONFIGURATION, html);
+        } catch (error) {
+          logger.error(
+            "Failed to format post content with Seonbi native: {error}",
+            {
+              error,
+            },
+          );
+          return html;
+        }
+      };
+    } catch {
+      logger.error(
+        "SEONBI_NATIVE is enabled but @seonbi/node is not installed",
+      );
+    }
+  }
+
+  if (SEONBI_URL != null) {
+    return async (html: string): Promise<string> => {
+      const response = await fetch(SEONBI_URL, {
+        method: "POST",
+        body: JSON.stringify({
+          ...SEONBI_CONFIGURATION,
+          content: html,
+        }),
+      });
+      try {
+        const seonbiResult = await response.json();
+        if (seonbiResult.success) {
+          if (
+            Array.isArray(seonbiResult.warnings) &&
+            seonbiResult.warnings.length > 0
+          ) {
+            logger.warn("Seonbi warnings: {warnings}", {
+              warnings: seonbiResult.warnings,
+            });
+          }
+          return seonbiResult.content;
+        }
+        logger.error("Seonbi failed to format post content: {message}", {
+          message: seonbiResult.message,
+        });
+      } catch (error) {
+        logger.error("Failed to format post content with Seonbi: {error}", {
+          error,
+        });
+      }
+      return html;
+    };
+  }
+
+  return async (html: string) => html;
+}
+
+function getPostContentTransformer(
+  language: string | null | undefined,
+): PostContentTransformer | null {
+  if (language === "ko" || language?.startsWith("ko-")) {
+    return koPostContentTransformer;
+  }
+  return null;
+}
 
 export async function formatPostContent(
   db: PgDatabase<
@@ -280,56 +378,9 @@ export async function formatPostContent(
   },
 ): Promise<FormatResult> {
   const result = await formatText(db, text, options);
-  if (
-    SEONBI_URL != null &&
-    (language === "ko" || language?.startsWith("ko-"))
-  ) {
-    const response = await fetch(SEONBI_URL, {
-      method: "POST",
-      body: JSON.stringify({
-        content: result.html,
-        contentType: "text/html",
-        quote: "HorizontalCornerBrackets",
-        cite: "AngleQuotes",
-        arrow: {
-          bidirArrow: true,
-          doubleArrow: true,
-        },
-        ellipsis: true,
-        emDash: true,
-        stop: "Horizontal",
-        hanja: {
-          rendering: "HanjaInRuby",
-          reading: {
-            initialSoundLaw: true,
-            useDictionaries: ["kr-stdict"],
-            dictionary: {},
-          },
-        },
-      }),
-    });
-    try {
-      const seonbiResult = await response.json();
-      if (seonbiResult.success) {
-        result.html = seonbiResult.content;
-        if (
-          Array.isArray(seonbiResult.warnings) &&
-          seonbiResult.warnings.length > 0
-        ) {
-          logger.warn("Seonbi warnings: {warnings}", {
-            warnings: seonbiResult.warnings,
-          });
-        }
-      } else {
-        logger.error("Seonbi failed to format post content: {message}", {
-          message: seonbiResult.message,
-        });
-      }
-    } catch (error) {
-      logger.error("Failed to format post content with Seonbi: {error}", {
-        error,
-      });
-    }
+  const transformer = getPostContentTransformer(language);
+  if (transformer != null) {
+    result.html = await transformer(result.html);
   }
   return result;
 }