diff --git a/supabase/functions/buildium-payee-backfill/index.ts b/supabase/functions/buildium-payee-backfill/index.ts
new file mode 100644
index 0000000..9c61074
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+++ b/supabase/functions/buildium-payee-backfill/index.ts
@@ -0,0 +1,256 @@
+// buildium-payee-backfill
+// One-off-style backfill: the GL CSV/pull imports only captured Buildium's
+// per-entry Description (the transaction *type* — "Charge", "Payment", "Bill",
+// "Check 1153"), so imported journal_entries carry no payor/payee. This pulls
+// Buildium's GL *transactions* for a company's window, extracts the party name
+// (vendor for bills/checks, owner/unit/tenant for charges/payments), and writes
+// it onto accounting.journal_entries.description, matched by external_id (the
+// Buildium transaction id).
+//
+// Body:
+//   companyId   (required) accounting.companies.id
+//   dateFrom    (required) ISO date, inclusive
+//   dateTo      (optional) ISO date, inclusive (default today)
+//   mode        "sample" | "dry" | "apply"   (default "dry")
+//                 sample — return raw Buildium GL-transaction JSON, write nothing
+//                 dry    — compute new descriptions + counts, write nothing
+//                 apply  — update journal_entries.description
+//   sampleSize  (sample mode) number of raw transactions to return (default 5)
+import { createClient } from "https://esm.sh/@supabase/supabase-js@2.49.1";
+
+const corsHeaders = {
+  "Access-Control-Allow-Origin": "*",
+  "Access-Control-Allow-Headers": "authorization, x-client-info, apikey, content-type",
+};
+const BUILDIUM_BASE = "https://api.buildium.com";
+const wait = (ms: number) => new Promise((r) => setTimeout(r, ms));
+const norm = (v: unknown) => String(v ?? "").toLowerCase().replace(/[^a-z0-9]+/g, " ").replace(/\s+/g, " ").trim();
+const json = (b: unknown, s = 200) =>
+  new Response(JSON.stringify(b), { status: s, headers: { ...corsHeaders, "Content-Type": "application/json" } });
+
+async function buildiumFetch(path: string, clientId: string, clientSecret: string, params?: URLSearchParams) {
+  const url = new URL(`${BUILDIUM_BASE}${path}`);
+  if (params) url.search = params.toString();
+  for (let attempt = 0; attempt < 4; attempt++) {
+    const res = await fetch(url.toString(), {
+      headers: { "x-buildium-client-id": clientId, "x-buildium-client-secret": clientSecret, Accept: "application/json" },
+    });
+    if (res.ok) return res.json();
+    const text = await res.text();
+    if ((res.status === 429 || res.status >= 500) && attempt < 3) {
+      const ra = Number(res.headers.get("Retry-After") ?? "");
+      await wait(Number.isFinite(ra) && ra > 0 ? ra * 1000 : 600 * Math.pow(2, attempt));
+      continue;
+    }
+    throw new Error(`Buildium ${path} [${res.status}]: ${text}`);
+  }
+  throw new Error(`Buildium ${path} failed after retries`);
+}
+
+async function buildiumFetchAll(path: string, clientId: string, clientSecret: string, base?: URLSearchParams) {
+  const all: any[] = [];
+  let offset = 0;
+  const limit = 1000;
+  while (true) {
+    const params = new URLSearchParams(base);
+    params.set("offset", String(offset));
+    params.set("limit", String(limit));
+    const page = await buildiumFetch(path, clientId, clientSecret, params);
+    if (!Array.isArray(page) || page.length === 0) break;
+    all.push(...page);
+    offset += page.length;
+  }
+  return all;
+}
+
+// Build unitId → owner name(s) for one association. /v1/associations/owners
+// returns owners with an OwnershipAccounts array; each entry ties the owner to
+// a UnitId within a specific AssociationId. A unit can have co-owners, so we
+// collect unique names and join up to two.
+async function buildOwnerByUnit(clientId: string, clientSecret: string, bAssocId: string) {
+  const params = new URLSearchParams();
+  params.append("associationids", String(bAssocId));
+  const owners = await buildiumFetchAll("/v1/associations/owners", clientId, clientSecret, params);
+  const namesByUnit = new Map<string, string[]>();
+  for (const o of owners) {
+    const name = [o?.FirstName, o?.LastName].filter(Boolean).join(" ").trim();
+    if (!name) continue;
+    for (const oa of o?.OwnershipAccounts ?? []) {
+      if (String(oa?.AssociationId ?? "") !== String(bAssocId)) continue;
+      const uid = String(oa?.UnitId ?? "");
+      if (!uid) continue;
+      const arr = namesByUnit.get(uid) ?? [];
+      if (!arr.includes(name)) arr.push(name);
+      namesByUnit.set(uid, arr);
+    }
+  }
+  const ownerByUnit = new Map<string, string>();
+  for (const [uid, arr] of namesByUnit) ownerByUnit.set(uid, arr.slice(0, 2).join(" & "));
+  return ownerByUnit;
+}
+
+// Extract the party name from a Buildium GL transaction.
+//  • Bill / Check / EFT / many Payments expose PaymentDetail.Payee.Name
+//    (vendor or owner) directly.
+//  • Owner-side Charge / ApplyDeposit carry only UnitId → resolve to owner name.
+//  • Fall back to the raw UnitNumber so something identifying still shows.
+function extractPayee(tx: any, ownerByUnit: Map<string, string>): string | null {
+  const direct = tx?.PaymentDetail?.Payee?.Name;
+  if (typeof direct === "string" && direct.trim()) return direct.trim();
+
+  const uid = tx?.UnitId != null ? String(tx.UnitId) : "";
+  if (uid && ownerByUnit.has(uid)) return ownerByUnit.get(uid)!;
+
+  const unitNo = tx?.UnitNumber;
+  if (typeof unitNo === "string" && unitNo.trim()) return `Unit ${unitNo.trim()}`;
+  return null;
+}
+
+Deno.serve(async (req) => {
+  if (req.method === "OPTIONS") return new Response(null, { headers: corsHeaders });
+  try {
+    const authHeader = req.headers.get("Authorization");
+    if (!authHeader?.startsWith("Bearer ")) return json({ error: "Unauthorized" }, 401);
+
+    const supabaseUrl = Deno.env.get("SUPABASE_URL")!;
+    const serviceKey = Deno.env.get("SUPABASE_SERVICE_ROLE_KEY")!;
+    const clientId = Deno.env.get("BUILDIUM_API_KEY") ?? "";
+    const clientSecret = Deno.env.get("BUILDIUM_API_SECRET") ?? "";
+    if (!clientId || !clientSecret) return json({ error: "Buildium API credentials not configured" }, 500);
+
+    const body = await req.json().catch(() => ({} as any));
+    const companyId = String(body?.companyId ?? "");
+    const dateFrom = String(body?.dateFrom ?? "");
+    const dateTo = String(body?.dateTo ?? new Date().toISOString().slice(0, 10));
+    const mode = String(body?.mode ?? "dry");
+    const sampleSize = Number(body?.sampleSize ?? 5);
+    if (!companyId || !dateFrom) return json({ error: "companyId and dateFrom are required" }, 400);
+
+    const supabase = createClient(supabaseUrl, serviceKey);
+
+    // Resolve the Buildium association by the local association's name.
+    const { data: company, error: cErr } = await supabase.schema("accounting")
+      .from("companies").select("id, name, association_id").eq("id", companyId).maybeSingle();
+    if (cErr) throw cErr;
+    if (!company) return json({ error: "company not found" }, 404);
+
+    const { data: assoc } = await supabase.from("associations").select("id, name").eq("id", company.association_id).maybeSingle();
+    const buildiumAssocs = await buildiumFetchAll("/v1/associations", clientId, clientSecret);
+    const bAssocId = buildiumAssocs.find((a: any) => norm(a.Name) === norm(assoc?.name))?.Id;
+    if (!bAssocId) return json({ error: `No Buildium association matches "${assoc?.name}"` }, 400);
+
+    // /v1/generalledger/transactions requires glaccountids. Gather every GL
+    // account id for the chart (children nest under SubAccounts) plus inactive
+    // bank GL accounts, then chunk them into the transactions call (the URL
+    // can't hold the whole chart at once). Dedupe transactions by Id.
+    const glAccounts = await buildiumFetchAll("/v1/glaccounts", clientId, clientSecret);
+    const glIds = new Set<string>();
+    const addGl = (g: any) => {
+      if (!g?.Id) return;
+      glIds.add(String(g.Id));
+      if (Array.isArray(g.SubAccounts)) for (const s of g.SubAccounts) addGl(s);
+    };
+    for (const g of glAccounts) addGl(g);
+    for (const b of await buildiumFetchAll("/v1/bankaccounts", clientId, clientSecret)) {
+      const gid = String(b.GLAccount?.Id ?? b.Id ?? "");
+      if (gid) glIds.add(gid);
+    }
+    const allGlIds = [...glIds];
+
+    // Pull GL transactions for the window. /v1/generalledger/transactions is the
+    // Journal view — one row per transaction with its Id, type and party data.
+    const txById = new Map<string, any>();
+    const CHUNK = 50;
+    for (let i = 0; i < allGlIds.length; i += CHUNK) {
+      const params = new URLSearchParams();
+      params.set("startdate", dateFrom);
+      params.set("enddate", dateTo);
+      params.set("entitytype", "Association");
+      params.set("entityid", String(bAssocId));
+      for (const id of allGlIds.slice(i, i + CHUNK)) params.append("glaccountids", id);
+      const page = await buildiumFetchAll("/v1/generalledger/transactions", clientId, clientSecret, params);
+      for (const tx of page) { const id = String(tx?.Id ?? ""); if (id) txById.set(id, tx); }
+    }
+    const txns = [...txById.values()];
+
+    if (mode === "sample") {
+      const ownersParams = new URLSearchParams();
+      ownersParams.append("associationids", String(bAssocId));
+      const owners = await buildiumFetchAll("/v1/associations/owners", clientId, clientSecret, ownersParams).catch((e) => [{ ownersError: String(e) }]);
+      return json({
+        mode, company: company.name, bAssocId, window: [dateFrom, dateTo],
+        pulled: txns.length,
+        ownersCount: Array.isArray(owners) ? owners.length : 0,
+        ownersSample: (owners || []).slice(0, 3),
+        sample: txns.slice(0, sampleSize),
+      });
+    }
+
+    const ownerByUnit = await buildOwnerByUnit(clientId, clientSecret, String(bAssocId));
+
+    // Map Buildium tx id → extracted party name.
+    const payeeById = new Map<string, string>();
+    const byType: Record<string, { total: number; named: number }> = {};
+    for (const tx of txns) {
+      const id = String(tx?.Id ?? "");
+      if (!id) continue;
+      const type = String(tx?.TransactionType ?? "?");
+      byType[type] ??= { total: 0, named: 0 };
+      byType[type].total++;
+      const name = extractPayee(tx, ownerByUnit);
+      if (name) { payeeById.set(id, name); byType[type].named++; }
+    }
+
+    // Load this company's imported entries and compute the new description.
+    const entries: { id: string; external_id: string; description: string }[] = [];
+    for (let offset = 0; ; offset += 1000) {
+      const { data: rows, error } = await supabase.schema("accounting")
+        .from("journal_entries")
+        .select("id, external_id, description")
+        .eq("company_id", companyId)
+        .eq("external_source", "buildium_gl")
+        .order("id", { ascending: true })
+        .range(offset, offset + 999);
+      if (error) throw error;
+      for (const r of rows || []) entries.push(r as any);
+      if ((rows || []).length < 1000) break;
+    }
+
+    const updates: { id: string; before: string; after: string }[] = [];
+    let unmatched = 0;
+    for (const e of entries) {
+      const name = e.external_id ? payeeById.get(String(e.external_id)) : undefined;
+      if (!name) { unmatched++; continue; }
+      const base = String(e.description ?? "").trim();
+      // Don't double-append if a previous run already added the name.
+      if (base.includes(name)) continue;
+      const after = base ? `${base} · ${name}` : name;
+      if (after !== base) updates.push({ id: e.id, before: base, after });
+    }
+
+    let updated = 0;
+    if (mode === "apply") {
+      for (const u of updates) {
+        const { error } = await supabase.schema("accounting")
+          .from("journal_entries").update({ description: u.after }).eq("id", u.id);
+        if (error) throw error;
+        updated++;
+      }
+    }
+
+    return json({
+      mode, company: company.name, window: [dateFrom, dateTo],
+      pulledTxns: txns.length,
+      unitsWithOwner: ownerByUnit.size,
+      txnsWithName: payeeById.size,
+      byType,
+      entries: entries.length,
+      unmatched,
+      toUpdate: updates.length,
+      updated,
+      examples: updates.slice(0, 15),
+    });
+  } catch (e: any) {
+    return json({ error: String(e?.message ?? e) }, 500);
+  }
+});