diff --git a/src/lib/api.ts b/src/lib/api.ts
index b7bd184..fdc3723 100644
--- a/src/lib/api.ts
+++ b/src/lib/api.ts
@@ -17,6 +17,8 @@
  *   - `health()` GETs `/api/health` and returns `{ status, version }`.
  *   - `listBatches / getBatch / listClaims / listRemittances / listProviders
  *     / listActivity` are plain JSON GETs against the persistence surface.
+ *   - `listUnmatched / matchRemit / unmatchClaim` hit the reconciliation
+ *     surface. POSTs throw `ApiError` so callers can branch on `.status`.
  */
 
 import type {
@@ -24,6 +26,7 @@ import type {
   ClaimPayment,
   Envelope,
   FinancialInfo,
+  MatchResponse,
   NdjsonEvent,
   ParseResult837,
   ParseResult835,
@@ -31,6 +34,8 @@ import type {
   Payer835,
   Payee835,
   ReassociationTrace,
+  UnmatchedClaim,
+  UnmatchedResponse,
   BatchSummary as ParserBatchSummary,
 } from "@/types";
 
@@ -147,6 +152,16 @@ function notConfiguredError(): Error {
   );
 }
 
+/**
+ * Error thrown for non-2xx responses. Carries the HTTP `status` so callers can
+ * branch on it (e.g. 404 vs 500) without parsing the message string.
+ */
+export class ApiError extends Error {
+  constructor(public status: number, message: string) {
+    super(message);
+  }
+}
+
 function joinUrl(path: string): string {
   return `${BASE_URL.replace(/\/$/, "")}${path}`;
 }
@@ -436,6 +451,61 @@ async function listActivity<T = unknown>(
   return (await res.json()) as PaginatedResponse<T>;
 }
 
+// ---------------------------------------------------------------------------
+// Public surface — reconciliation endpoints (sub-project 2)
+// POSTs throw `ApiError` so callers can inspect `.status`; the GET is shaped
+// like the other list endpoints above.
+// ---------------------------------------------------------------------------
+
+async function listUnmatched(): Promise<UnmatchedResponse> {
+  if (!isConfigured) throw notConfiguredError();
+  const res = await fetch(joinUrl(`/api/reconciliation/unmatched`), {
+    headers: { Accept: "application/json" },
+  });
+  if (!res.ok) {
+    const detail = await readErrorBody(res);
+    throw new ApiError(res.status, detail || res.statusText);
+  }
+  return (await res.json()) as UnmatchedResponse;
+}
+
+async function matchRemit(
+  claimId: string,
+  remitId: string
+): Promise<MatchResponse> {
+  if (!isConfigured) throw notConfiguredError();
+  const res = await fetch(joinUrl(`/api/reconciliation/match`), {
+    method: "POST",
+    headers: {
+      "Content-Type": "application/json",
+      Accept: "application/json",
+    },
+    body: JSON.stringify({ claim_id: claimId, remit_id: remitId }),
+  });
+  if (!res.ok) {
+    const detail = await readErrorBody(res);
+    throw new ApiError(res.status, detail || res.statusText);
+  }
+  return (await res.json()) as MatchResponse;
+}
+
+async function unmatchClaim(claimId: string): Promise<{ claim: UnmatchedClaim }> {
+  if (!isConfigured) throw notConfiguredError();
+  const res = await fetch(joinUrl(`/api/reconciliation/unmatch`), {
+    method: "POST",
+    headers: {
+      "Content-Type": "application/json",
+      Accept: "application/json",
+    },
+    body: JSON.stringify({ claim_id: claimId }),
+  });
+  if (!res.ok) {
+    const detail = await readErrorBody(res);
+    throw new ApiError(res.status, detail || res.statusText);
+  }
+  return (await res.json()) as { claim: UnmatchedClaim };
+}
+
 export const api = {
   isConfigured,
   baseUrl: BASE_URL,
@@ -448,4 +518,7 @@ export const api = {
   listRemittances,
   listProviders,
   listActivity,
+  listUnmatched,
+  matchRemit,
+  unmatchClaim,
 };