diff --git a/packages/db/src/seeding-datafiles.ts b/packages/db/src/seeding-datafiles.ts
index e69de29..e14535b 100644
--- a/packages/db/src/seeding-datafiles.ts
+++ b/packages/db/src/seeding-datafiles.ts
@@ -0,0 +1,212 @@
+import fs from "node:fs/promises";
+import { and, count, eq, inArray } from "drizzle-orm";
+
+import { SUPPORTED_LANGUAGE_CODES, SUPPORTED_POS } from "@glossa/shared";
+import { db } from "@glossa/db";
+import { terms, translations, term_glosses } from "@glossa/db/schema";
+
+type POS = (typeof SUPPORTED_POS)[number];
+type LanguageCode = (typeof SUPPORTED_LANGUAGE_CODES)[number];
+
+type SynsetRecord = {
+  source_id: string;
+  pos: POS;
+  translations: Partial<Record<LanguageCode, string[]>>;
+  glosses: Partial<Record<LanguageCode, string[]>>;
+};
+
+const dataDir = "./src/data/datafiles/";
+const BATCH_SIZE = 500;
+
+// ────────────────────────────────────────────────────────────
+// Helpers
+// ────────────────────────────────────────────────────────────
+
+function chunk<T>(arr: T[], size: number): T[][] {
+  const out: T[][] = [];
+  for (let i = 0; i < arr.length; i += size) out.push(arr.slice(i, i + size));
+  return out;
+}
+
+function fmt(n: number): string {
+  return n.toLocaleString("en-US");
+}
+
+// ────────────────────────────────────────────────────────────
+// Stats
+// ────────────────────────────────────────────────────────────
+
+const stats = {
+  terms: { inserted: 0, skipped: 0 },
+  translations: { inserted: 0, skipped: 0 },
+  glosses: { inserted: 0, skipped: 0 },
+};
+
+// ────────────────────────────────────────────────────────────
+// Per-batch processing
+// ────────────────────────────────────────────────────────────
+
+async function processBatch(batch: SynsetRecord[]): Promise<void> {
+  // 1. Insert terms — idempotency key: (source, source_id)
+  const termValues = batch.map((r) => ({
+    source: "omw" as const,
+    source_id: r.source_id,
+    pos: r.pos,
+  }));
+
+  const insertedTerms = await db
+    .insert(terms)
+    .values(termValues)
+    .onConflictDoNothing()
+    .returning({ id: terms.id });
+
+  stats.terms.inserted += insertedTerms.length;
+  stats.terms.skipped += batch.length - insertedTerms.length;
+
+  // 2. Resolve UUIDs for every source_id in this batch (new + pre-existing).
+  //    We can't rely solely on the .returning() above because onConflictDoNothing
+  //    returns nothing for rows that already existed.
+  const sourceIds = batch.map((r) => r.source_id);
+  const termRows = await db
+    .select({ id: terms.id, source_id: terms.source_id })
+    .from(terms)
+    .where(and(eq(terms.source, "omw"), inArray(terms.source_id, sourceIds)));
+
+  const sourceIdToTermId = new Map(termRows.map((r) => [r.source_id, r.id]));
+
+  // 3. Build and insert translation rows
+  const translationRows = batch.flatMap((r) => {
+    const termId = sourceIdToTermId.get(r.source_id);
+    if (!termId) return [];
+    return Object.entries(r.translations).flatMap(([lang, lemmas]) =>
+      (lemmas ?? []).map((text) => ({
+        term_id: termId,
+        language_code: lang as LanguageCode,
+        text,
+      })),
+    );
+  });
+
+  for (const tBatch of chunk(translationRows, BATCH_SIZE)) {
+    const inserted = await db
+      .insert(translations)
+      .values(tBatch)
+      .onConflictDoNothing()
+      .returning({ id: translations.id });
+
+    stats.translations.inserted += inserted.length;
+    stats.translations.skipped += tBatch.length - inserted.length;
+  }
+
+  // 4. Build and insert gloss rows
+  const glossRows = batch.flatMap((r) => {
+    const termId = sourceIdToTermId.get(r.source_id);
+    if (!termId) return [];
+    return Object.entries(r.glosses ?? {}).flatMap(([lang, texts]) =>
+      (texts ?? []).map((text) => ({
+        term_id: termId,
+        language_code: lang as LanguageCode,
+        text,
+      })),
+    );
+  });
+
+  for (const gBatch of chunk(glossRows, BATCH_SIZE)) {
+    const inserted = await db
+      .insert(term_glosses)
+      .values(gBatch)
+      .onConflictDoNothing()
+      .returning({ id: term_glosses.id });
+
+    stats.glosses.inserted += inserted.length;
+    stats.glosses.skipped += gBatch.length - inserted.length;
+  }
+}
+
+// ────────────────────────────────────────────────────────────
+// Main
+// ────────────────────────────────────────────────────────────
+
+const main = async () => {
+  console.log("\n##########################################");
+  console.log("Glossa — OMW seed");
+  console.log("##########################################\n");
+
+  // One file per POS — names are derived from SUPPORTED_POS so adding a new
+  // constant value automatically picks up a new file on the next run.
+  const posToFile = Object.fromEntries(
+    SUPPORTED_POS.map((pos) => [pos, `omw-${pos}.json`]),
+  ) as Record<POS, string>;
+
+  for (const pos of SUPPORTED_POS) {
+    const filename = posToFile[pos];
+    const filepath = dataDir + filename;
+
+    console.log(`📄 ${filename}`);
+
+    let records: SynsetRecord[];
+    try {
+      const raw = await fs.readFile(filepath, "utf8");
+      records = JSON.parse(raw) as SynsetRecord[];
+    } catch (e) {
+      console.warn(
+        `   ⚠️  Skipping — could not read file: ${(e as Error).message}\n`,
+      );
+      continue;
+    }
+
+    console.log(`   Loaded ${fmt(records.length)} synsets`);
+
+    const batches = chunk(records, BATCH_SIZE);
+
+    for (const [i, batch] of batches.entries()) {
+      // Progress every 5 000 synsets
+      if (i > 0 && i % 10 === 0) {
+        const processed = i * BATCH_SIZE;
+        console.log(`   ⏳ ${fmt(processed)} / ${fmt(records.length)}`);
+      }
+      await processBatch(batch);
+    }
+
+    console.log(`   ✅ Done\n`);
+  }
+
+  // ── Summary ───────────────────────────────────────────────
+
+  console.log("##########################################");
+  console.log("Summary");
+  console.log("##########################################\n");
+
+  const pad = (label: string) => label.padEnd(14);
+
+  console.log(
+    `${pad("Terms:")}inserted ${fmt(stats.terms.inserted)}, skipped ${fmt(stats.terms.skipped)}`,
+  );
+  console.log(
+    `${pad("Translations:")}inserted ${fmt(stats.translations.inserted)}, skipped ${fmt(stats.translations.skipped)}`,
+  );
+  console.log(
+    `${pad("Glosses:")}inserted ${fmt(stats.glosses.inserted)}, skipped ${fmt(stats.glosses.skipped)}`,
+  );
+
+  // Query actual DB totals — insert-based counters show 0 on re-runs.
+  console.log("\nCoverage per language (total in DB):");
+  for (const lang of SUPPORTED_LANGUAGE_CODES) {
+    const [tRow] = await db
+      .select({ n: count() })
+      .from(translations)
+      .where(eq(translations.language_code, lang));
+    const [gRow] = await db
+      .select({ n: count() })
+      .from(term_glosses)
+      .where(eq(term_glosses.language_code, lang));
+    console.log(
+      `  ${lang}: ${fmt(tRow?.n ?? 0)} translations, ${fmt(gRow?.n ?? 0)} glosses`,
+    );
+  }
+};
+
+main().catch((err) => {
+  console.error(err);
+  process.exit(1);
+});