diff --git a/src/api.ts b/src/api.ts
index 9000093..82c3d36 100644
--- a/src/api.ts
+++ b/src/api.ts
@@ -1,764 +1,33 @@
-import { BatchCall } from "./types/batch";
-
-// Resolves the indexer API base URL from VITE_API_URL. Leaving it unset
-// keeps the relative "/api" path, which relies on the dev-server proxy
-// (vite.config.ts) or nginx (nginx.conf) to reach the indexer.
-export function resolveApiBase(
-  env: { VITE_API_URL?: string } = import.meta.env,
-): string {
-  return `${env.VITE_API_URL ?? ""}/api`;
-}
-
-const BASE = resolveApiBase();
-
-export interface SpecType {
-  kind: "struct" | "enum" | "union" | "error_enum";
-  name: string;
-  fields?: { name: string; type: string }[];
-  cases?: { name: string; value?: number; types?: string[] }[];
-}
-
-export interface StorageWrite {
-  tier: "instance" | "persistent" | "temporary";
-  contractId: string;
-  key: string;
-  changeType: "created" | "updated";
-}
-
-export interface StorageTiers {
-  instance: StorageWrite[];
-  persistent: StorageWrite[];
-  temporary: StorageWrite[];
-}
-
-export interface FeeBumpInfo {
-  /** Outer fee-bump feeSource — pays the network fee. */
-  sponsor: string;
-  /** Inner transaction source account (channel account — provides sequence number for parallel execution). */
-  inner_source: string;
-  /** Actual signing identity from Soroban auth credentials (who authorised the contract logic). */
-  actual_caller: string | null;
-}
-
-// Factory deployment tracking
-export interface FactoryDeploymentContract {
-  contractId: string;
-  wasmHash: string | null;
-  deploymentMethod: string;
-  index: number;
-}
-
-export interface FactoryDeploymentTree {
-  factoryContractId: string | null;
-  contracts: FactoryDeploymentContract[];
-}
-
-// CAP-0080 ZK host function types
-export interface ZkHostCall {
-  fn_name: string;
-  curve: "BN254" | "BLS12-381";
-  kind:
-    | "msm"
-    | "pairing"
-    | "scalar_field"
-    | "map_to_curve"
-    | "hash_to_curve"
-    | "other";
-  cpu_native: number;
-  cpu_legacy: number;
-}
-
-export interface ZkCostDelta {
-  total_native: number;
-  total_legacy: number;
-  saved_cpu: number;
-  saved_pct: number;
-}
-
-export interface HeuristicParam {
-  index: number;
-  raw: string;
-  type:
-    | "Address"
-    | "ContractId"
-    | "Amount"
-    | "Hash"
-    | "Symbol"
-    | "Boolean"
-    | "Unknown";
-  value: string;
-  confidence: "likely" | "possible";
-}
-
-export interface DecodedEvent {
-  seq: number;
-  contract_id: string;
-  function: string;
-  ledger: number;
-  description: string;
-  raw_topics: string[];
-  tx_hash?: string;
-  // Soroban resource gas costs
-  cpu_instructions?: number;
-  mem_bytes?: number;
-  fee_charged?: number;
-  // state-bloat risk
-  is_high_bloat_risk?: boolean;
-  // upgrade lineage
-  upgrade_info?: { type: "upgrade"; oldHash: string; newHash: string };
-  // storage tier breakdown
-  storage_tiers?: StorageTiers;
-  // clawback compliance flag
-  is_clawback?: boolean;
-  // AMM swap path hops ["10 USDC", "9.1 EURC", "5.2 XLM"]
-  swap_path?: string[];
-  // Protocol 26: TTL extension host function data
-  ttl_extension?: {
-    fn_name: string | null;
-    extend_to: number | null;
-    min_extension: number | null;
-    max_extension: number | null;
-  };
-  // fee-bump chain of custody
-  fee_bump?: FeeBumpInfo | null;
-  // state archival / restoration info (RestoreFootprintOp)
-  archival_info?: {
-    isRestoreOp: boolean;
-    revivedKeys: {
-      type: string;
-      label: string;
-      contractId?: string;
-      wasmHash?: string;
-      dataKey?: string;
-      durability?: string;
-    }[];
-    keyCount: number;
-    feePaid: number | null;
-  } | null;
-  // CAP-0080 ZK host function telemetry (Protocol 26)
-  zk_host_calls?: { calls: ZkHostCall[]; delta: ZkCostDelta | null };
-  // Heuristic fallback params: present when no ABI is registered
-  heuristic_params?: HeuristicParam[];
-  // SAC implicit side-effect (auto-created account or trustline)
-  sac_side_effect?: "account_created" | "trustline_opened";
-  // Factory deployment trace
-  factory_deployment?: FactoryDeploymentTree;
-}
-
-export interface SourceFile {
-  path: string;
-  content: string;
-}
-
-export interface MigrationStatus {
-  pending: boolean;
-  upgradedAtLedger: number | null;
-  migratedAtLedger: number | null;
-}
-
-export interface DependencyAdvisoryPackage {
-  name: string;
-  currentVersion: string;
-  latestVersion: string;
-  upgradeUrl: string;
-}
-
-export interface DependencyAdvisory {
-  outdated: boolean;
-  summary: string;
-  packages: DependencyAdvisoryPackage[];
-}
-
-export interface ContractMeta {
-  id: string;
-  version: number;
-  name: string;
-  description: string;
-  functions: { name: string; description: string }[];
-  source?: string;
-  source_file?: string;
-  source_files?: SourceFile[];
-  dependency_advisory?: DependencyAdvisory | null;
-}
-
-export type SearchKind = "contract" | "event" | "wallet";
-
-export interface SearchContract {
-  id: string;
-  name: string;
-  description?: string | null;
-  functions?: { name: string; description?: string }[];
-  event_count: number;
-}
-
-export interface SearchWallet {
-  address: string;
-  event_count: number;
-  first_seen_ledger: number | null;
-  last_seen_ledger: number | null;
-  contracts: string[];
-}
-
-export interface SearchSuggestion {
-  kind: SearchKind;
-  label: string;
-  route: string;
-  meta: Record<string, unknown>;
-}
-
-export interface SearchResponse {
-  query: string;
-  contracts: SearchContract[];
-  events: DecodedEvent[];
-  wallets: SearchWallet[];
-  suggestions: SearchSuggestion[];
-}
-
-export interface BurnAlert {
-  contractId: string;
-  ledger: number;
-  burnedPct: number;
-  burnedAmount: string;
-  flaggedAt: number;
-}
-
-// paginated contract transaction response
-export interface ContractTransactionsResponse {
-  data: DecodedEvent[];
-  pagination: {
-    page: number;
-    limit: number;
-    total: number;
-    total_pages: number;
-    has_next: boolean;
-  };
-}
-
-// contract dependency graph
-export interface GraphNode3D {
-  id: string;
-  callCount: number;
-}
-
-export interface GraphLink3D {
-  source: string;
-  target: string;
-  value: number;
-}
-
-export interface ContractGraphData {
-  nodes: GraphNode3D[];
-  links: GraphLink3D[];
-}
-
-async function get<T>(path: string): Promise<T> {
-  const res = await fetch(BASE + path);
-  if (!res.ok) throw new Error(`API ${res.status}: ${path}`);
-  return res.json();
-}
-
-export interface SimResult {
-  success: boolean;
-  returnValue?: string;
-  cost?: { cpuInsns: string; memBytes: string };
-  error?: string;
-}
-
-export interface PrivilegedRole {
-  role: string;
-  address: string;
-  ledger: number | null;
-  updated_at: string;
-}
-
-// // source verification signature
-export interface SourceVerification {
-  signer: string;
-  signature: string;
-  compiler_hash: string;
-  wasm_hash: string;
-  submitted_at: string;
-}
-
-// storage state diff entry
-export interface StateDiff {
-  ledger: number;
-  tx_hash: string | null;
-  key: string;
-  tier?: string;
-  old_value: string | null;
-  new_value: string | null;
-  change_type: "created" | "updated" | "removed";
-  created_at: string;
-}
-
-// sub-invocation record
-export interface SubInvocation {
-  id: number;
-  parent_tx_hash: string;
-  depth: number;
-  contract_id: string;
-  function: string;
-  args: unknown[] | null;
-  ledger: number;
-}
-
-// transaction status
-export interface TxStatusResponse {
-  tx_hash: string;
-  status: "pending" | "success" | "failed";
-  ledger: number | null;
-  error?: string | null;
-}
-
-// Live TTL status for contract instance and code entries
-export interface ContractTTL {
-  contract_id: string;
-  current_ledger: number;
-  instance: { live_until_ledger: number | null };
-  code: { live_until_ledger: number | null };
-}
-
-export interface CircuitBreakerStatus {
-  has_circuit_breaker: boolean;
-  is_paused: boolean;
-  pause_status_ledger: number | null;
-}
-
-export interface RwaMetadata {
-  is_rwa: boolean;
-  rwa_type: string | null;
-}
-
-export interface NetworkStatus {
-  network: string;
-  deployed: boolean;
-  wasmHash?: string;
-  balance?: string;
-  error?: string;
-}
-
-export interface NetworkComparisonResult {
-  contractId: string;
-  statuses: NetworkStatus[];
-  hasVersionMismatch: boolean;
-}
-
-export interface GraphNode {
-  id: string;
-  label: string;
-  type: string;
-}
-
-export interface GraphEdge {
-  source: string;
-  target: string;
-  label?: string;
-  amount?: string;
-}
-
-export interface AddressGraphData {
-  nodes: GraphNode[];
-  edges: GraphEdge[];
-}
-
-// Sub-invocation filter options for the advanced search endpoint
-export interface SubInvocationFilter {
-  contract?: string;
-  function?: string;
-  depth_min?: number;
-  depth_max?: number;
-  gas_min?: number;
-  gas_max?: number;
-  date_from?: string;
-  date_to?: string;
-  arg_query?: string;
-  has_reentrancy?: boolean;
-  tx_hash?: string;
-  ledger_min?: number;
-  ledger_max?: number;
-}
-
-// Extended sub-invocation record with gas and reentrancy metadata
-export interface SubInvocationExtended extends SubInvocation {
-  cpu_instructions?: number;
-  mem_bytes?: number;
-  fee_charged?: number;
-  has_reentrancy?: boolean;
-  gas_cost?: number;
-  is_reentrant?: boolean;
-  contract_type?: "token" | "dex" | "lending" | "nft" | "other";
-}
-
-// Aggregate analytics across all sub-invocations
-export interface SubInvocationAnalytics {
-  total: number;
-  avg_depth: number;
-  max_depth: number;
-  top_contracts: { contract_id: string; call_count: number }[];
-  depth_distribution: { depth: number; count: number }[];
-}
-
-// Per-transaction call-path metrics
-export interface SubInvocationCallMetrics {
-  tx_hash: string;
-  total_calls: number;
-  max_depth: number;
-  unique_contracts: number;
-  has_reentrancy: boolean;
-  total_cpu?: number;
-  total_fee?: number;
-}
-
-// Cross-transaction tree diff result
-export interface TransactionTreeDiff {
-  added: SubInvocationExtended[];
-  removed: SubInvocationExtended[];
-  changed: { a: SubInvocationExtended; b: SubInvocationExtended }[];
-}
-
-export interface NodeMetrics {
-  url: string;
-  latencyAvgMs: number | null;
-  latencyP95Ms: number | null;
-  errorRate: number;
-  uptime: number;
-  lastLedger: number;
-  sampleCount: number;
-  history: number[];
-}
-
-export interface DoctorReport {
-  runtimes: Record<string, { status: string; version?: string; message: string }>;
-  database: { connected: boolean; message: string };
-  env: Record<string, { status: string; value: string; message: string }>;
-  ports: Record<string, { status: string; inUse: boolean; message: string }>;
-  system: {
-    disk: { status: string; freeGB?: string; message: string };
-    memory: { status: string; totalGB?: string; freeGB?: string; message: string };
-  };
-  gitHooks: { status: string; message: string };
-  docker: { status: string; message: string };
-}
-
-export const api = {
-  events: (params: {
-    contract?: string;
-    fn?: string;
-    page?: number;
-    type?: string;
-  }) => {
-    const q = new URLSearchParams();
-    if (params.contract) q.set("contract", params.contract);
-    if (params.fn) q.set("fn", params.fn);
-    if (params.page) q.set("page", String(params.page));
-    if (params.type) q.set("type", params.type);
-    return get<DecodedEvent[]>(`/events?${q}`);
-  },
-  event: (seq: number) => get<DecodedEvent>(`/events/${seq}`),
-  search: (q: string, limit = 10) => {
-    const params = new URLSearchParams();
-    params.set("q", q);
-    params.set("limit", String(limit));
-    return get<SearchResponse>(`/search?${params}`);
-  },
-  zkCosts: (seq: number) =>
-    get<{ calls: ZkHostCall[]; delta: ZkCostDelta | null }>(
-      `/events/${seq}/zk-costs`,
-    ),
-  contract: (id: string) => get<ContractMeta>(`/contracts/${id}`),
-  burnAlerts: (contract: string) =>
-    get<BurnAlert[]>(`/burn-alerts?contract=${contract}`),
-  migrationStatus: (id: string) =>
-    get<MigrationStatus>(`/contracts/${id}/migration-status`),
-  wallet: (address: string) => get<DecodedEvent[]>(`/wallet/${address}`),
-  roles: (id: string) => get<PrivilegedRole[]>(`/contracts/${id}/roles`),
-  networkComparison: (id: string) =>
-    get<NetworkComparisonResult>(`/contracts/${id}/network-comparison`),
-  addressGraph: (id: string) =>
-    get<AddressGraphData>(`/contracts/${id}/address-graph`),
-
-  // sub-invocations for a transaction
-  subInvocations: (txHash: string) =>
-    get<SubInvocation[]>(`/transactions/${txHash}/sub-invocations`),
-  // Events where contract appears directly OR as sub-invocation
-  eventsDeep: (contractId: string, page = 1) =>
-    get<DecodedEvent[]>(`/v1/contracts/${contractId}/events-deep?page=${page}`),
-
-  // transaction status (polling fallback; SSE via useTxStatus hook)
-  txStatus: (txHash: string) =>
-    get<TxStatusResponse>(`/transactions/${txHash}/status`),
-
-  // Circuit breaker status
-  circuitBreakerStatus: (id: string) =>
-    get<CircuitBreakerStatus>(`/contracts/${id}/circuit-breaker`),
-
-  // RWA token metadata
-  rwaMetadata: (id: string) =>
-    get<RwaMetadata>(`/contracts/${id}/rwa-metadata`),
-
-  downloadAbi: async (id: string) => {
-    const res = await fetch(`${BASE}/contracts/${id}/abi`);
-    if (!res.ok) throw new Error(`API ${res.status}: /contracts/${id}/abi`);
-    const blob = await res.blob();
-    const url = URL.createObjectURL(blob);
-    const a = document.createElement("a");
-    a.href = url;
-    a.download = `${id}.abi.json`;
-    document.body.appendChild(a);
-    a.click();
-    document.body.removeChild(a);
-    URL.revokeObjectURL(url);
-  },
-
-  // multi-sig source verification
-  sourceVerifications: (id: string, wasmHash?: string) => {
-    const q = wasmHash ? `?wasm_hash=${encodeURIComponent(wasmHash)}` : "";
-    return get<SourceVerification[]>(
-      `/contracts/${id}/source-verifications${q}`,
-    );
-  },
-  submitSourceVerification: (
-    id: string,
-    body: {
-      wasm_hash: string;
-      signer: string;
-      signature: string;
-      compiler_hash: string;
-    },
-  ) =>
-    fetch(`${BASE}/contracts/${id}/source-verifications`, {
-      method: "POST",
-      headers: { "Content-Type": "application/json" },
-      body: JSON.stringify(body),
-    }).then((r) => {
-      if (!r.ok) throw new Error(`API ${r.status}`);
-      return r.json();
-    }),
-
-  // live TTL status (instance + code expiration ledgers)
-  contractTTL: (id: string) => get<ContractTTL>(`/contracts/${id}/ttl`),
-
-  // state-diff timeline
-  stateDiffs: (id: string, key?: string) => {
-    const q = key ? `?key=${encodeURIComponent(key)}` : "";
-    return get<StateDiff[]>(`/contracts/${id}/state-diffs${q}`);
-  },
-
-  // global contract dependency graph
-  contractGraph: (limit = 500) =>
-    get<ContractGraphData>(`/contract-graph?limit=${limit}`),
-
-  // CAP-0077 quorum freeze status
-  quorumFreeze: (id: string) =>
-    get<{
-      is_frozen: boolean;
-      ledger: number;
-      tx_hash: string;
-      frozen_ids: string[];
-    }>(`/contracts/${id}/quorum-freeze`),
-
-  // Full contract spec (functions + custom types)
-  specFull: (id: string) =>
-    get<{
-      functions: { name: string; outputs?: string[] }[];
-      types: SpecType[];
-    }>(`/contracts/${id}/spec-full`),
-
-  // Batch Multi-Call endpoints
-  batchSimulate: (calls: BatchCall[], sourceAccount?: string) =>
-    fetch(`${BASE}/batch/simulate`, {
-      method: "POST",
-      headers: { "Content-Type": "application/json" },
-      body: JSON.stringify({ calls, sourceAccount }),
-    }).then((r) => r.json()),
-  batchEstimateGas: (calls: BatchCall[], sourceAccount?: string) =>
-    fetch(`${BASE}/batch/estimate-gas`, {
-      method: "POST",
-      headers: { "Content-Type": "application/json" },
-      body: JSON.stringify({ calls, sourceAccount }),
-    }).then((r) => r.json()),
-  batchOptimize: (calls: BatchCall[], sourceAccount?: string) =>
-    fetch(`${BASE}/batch/optimize`, {
-      method: "POST",
-      headers: { "Content-Type": "application/json" },
-      body: JSON.stringify({ calls, sourceAccount }),
-    }).then((r) => r.json()),
-  batchValidate: (calls: BatchCall[], sourceAccount?: string) =>
-    fetch(`${BASE}/batch/validate`, {
-      method: "POST",
-      headers: { "Content-Type": "application/json" },
-      body: JSON.stringify({ calls, sourceAccount }),
-    }).then((r) => r.json()),
-
-  // Batch types export
-  exportBatchAsHardhat: (calls: BatchCall[]) => {
-    const lines = [
-      "// Generated Hardhat script for Soroban batch calls",
-      "const { Server, Contract, TransactionBuilder, Networks, nativeToScVal } = require('@stellar/stellar-sdk');",
-      "",
-      "async function main() {",
-      "  const server = new Server(process.env.SOROBAN_RPC_URL || 'https://soroban-testnet.stellar.org');",
-      "  const source = process.env.SOROBAN_SOURCE || 'GAAZI4TCR3TY5OJHCTJC2A4QSY6CJWJH5IAJTGKIN2ER7LBNVKOCCWN';",
-      "  const account = await server.getAccount(source);",
-      "",
-      ...calls.flatMap((call, i) => [
-        `  const op${i + 1} = new Contract('${call.contractId}').call(`,
-        `    '${call.functionName}'${call.args.length ? "," : ""}`,
-        ...(call.args.length
-          ? call.args.map(
-              (arg) =>
-                `    nativeToScVal(${JSON.stringify(arg.value)}${arg.type ? `, { type: '${arg.type}' }` : ""}),`,
-            )
-          : []),
-        "  );",
-        "",
-      ]),
-      "  const tx = new TransactionBuilder(account, {",
-      "    fee: '100',",
-      "    networkPassphrase: Networks.TESTNET,",
-      "  })",
-      ...calls.map((_, i) => `    .addOperation(op${i + 1})`),
-      "      .setTimeout(30)",
-      "      .build();",
-      "",
-      "  const simulation = await server.simulateTransaction(tx);",
-      "  console.log(simulation);",
-      "}",
-      "",
-      "main().catch(console.error);",
-    ];
-    return lines.join("\n");
-  },
-  exportBatchAsCurl: (calls: BatchCall[], sourceAccount?: string) =>
-    JSON.stringify(
-      {
-        calls,
-        sourceAccount,
-      },
-      null,
-      2,
-    ),
-  exportBatchAsGraphQL: () =>
-    [
-      "mutation SimulateBatch($calls: [BatchCallInput!]!, $sourceAccount: String) {",
-      "  simulateBatch(calls: $calls, sourceAccount: $sourceAccount) {",
-      "    success",
-      "    results { callId success returnValue error }",
-      "    totalGas { cpuInsns memBytes fee }",
-      "  }",
-      "}",
-    ].join("\n"),
-  exportBatchAsJson: (calls: BatchCall[], sourceAccount?: string) =>
-    JSON.stringify(
-      {
-        calls,
-        sourceAccount,
-        generatedAt: new Date().toISOString(),
-      },
-      null,
-      2,
-    ),
-
-  // Issue #210: Sub-invocation search with 8+ filter types
-  searchSubInvocations: (filter: SubInvocationFilter) => {
-    const q = new URLSearchParams();
-    if (filter.contract) q.set("contract", filter.contract);
-    if (filter.depth_min != null) q.set("depth_min", String(filter.depth_min));
-    if (filter.depth_max != null) q.set("depth_max", String(filter.depth_max));
-    if (filter.gas_min != null) q.set("gas_min", String(filter.gas_min));
-    if (filter.gas_max != null) q.set("gas_max", String(filter.gas_max));
-    if (filter.function) q.set("function", filter.function);
-    if (filter.date_from) q.set("date_from", filter.date_from);
-    if (filter.date_to) q.set("date_to", filter.date_to);
-    if (filter.arg_query) q.set("arg_query", filter.arg_query);
-    if (filter.has_reentrancy != null)
-      q.set("has_reentrancy", String(filter.has_reentrancy));
-    if (filter.tx_hash) q.set("tx_hash", filter.tx_hash);
-    if (filter.ledger_min != null)
-      q.set("ledger_min", String(filter.ledger_min));
-    if (filter.ledger_max != null)
-      q.set("ledger_max", String(filter.ledger_max));
-    return get<SubInvocationExtended[]>(`/sub-invocations/search?${q}`);
-  },
-
-  // Issue #210: Global analytics for sub-invocations
-  subInvocationAnalytics: () =>
-    get<SubInvocationAnalytics>(`/sub-invocations/analytics`),
-
-  // Issue #210: Call-path metrics for a single transaction (6 analytical metrics)
-  callPathMetrics: (txHash: string) =>
-    get<SubInvocationCallMetrics>(`/transactions/${txHash}/call-path-metrics`),
-
-  // Issue #210: Cross-transaction tree diff
-  compareTransactionTrees: (txA: string, txB: string) =>
-    get<TransactionTreeDiff>(
-      `/transactions/compare?a=${encodeURIComponent(txA)}&b=${encodeURIComponent(txB)}`,
-    ),
-
-  // Issue #210: SSE stream URL builder for live sub-invocation feed
-  subInvocationStreamUrl: (
-    filter?: Pick<SubInvocationFilter, "contract" | "function">,
-  ) => {
-    const q = new URLSearchParams();
-    if (filter?.contract) q.set("contract", filter.contract);
-    if (filter?.function) q.set("function", filter.function);
-    return `${BASE}/sub-invocations/stream?${q}`;
-  },
-
-  // RPC metrics
-  rpcMetrics: () => get<NodeMetrics[]>("/rpc-metrics"),
-
-  // Admin Rate Limit Analytics
-  adminRateLimitHits: (token: string, minutes: number = 60) =>
-    fetch(`${BASE}/admin/analytics/rate-limit-hits?minutes=${minutes}`, {
-      headers: { Authorization: `Bearer ${token}` },
-    }).then((r) => {
-      if (!r.ok) throw new Error(`API ${r.status}`);
-      return r.json();
-    }),
-  adminTopUsers: (token: string, window: string = "24h") =>
-    fetch(`${BASE}/admin/analytics/top-users?window=${window}`, {
-      headers: { Authorization: `Bearer ${token}` },
-    }).then((r) => {
-      if (!r.ok) throw new Error(`API ${r.status}`);
-      return r.json();
-    }),
-  adminViolationHeatmap: (token: string) =>
-    fetch(`${BASE}/admin/analytics/violation-heatmap`, {
-      headers: { Authorization: `Bearer ${token}` },
-    }).then((r) => {
-      if (!r.ok) throw new Error(`API ${r.status}`);
-      return r.json();
-    }),
-  adminUpgradeRecommendations: (token: string) =>
-    fetch(`${BASE}/admin/analytics/upgrade-recommendations`, {
-      headers: { Authorization: `Bearer ${token}` },
-    }).then((r) => {
-      if (!r.ok) throw new Error(`API ${r.status}`);
-      return r.json();
-    }),
-
-  // Setup Page
-  setupDoctor: () => get<DoctorReport>("/setup/doctor"),
-  setupTestDb: (databaseUrl: string) =>
-    fetch(`${BASE}/setup/test-db`, {
-      method: "POST",
-      headers: { "Content-Type": "application/json" },
-      body: JSON.stringify({ databaseUrl }),
-    }).then((r) => r.json()),
-  setupSaveConfig: (config: { sorobanRpcUrl: string; databaseUrl: string; pollMs: string }) =>
-    fetch(`${BASE}/setup/save-config`, {
-      method: "POST",
-      headers: { "Content-Type": "application/json" },
-      body: JSON.stringify(config),
-    }).then((r) => r.json()),
-  setupDbInit: () =>
-    fetch(`${BASE}/setup/db-init`, {
-      method: "POST",
-      headers: { "Content-Type": "application/json" },
-    }).then((r) => {
-      if (!r.ok) throw new Error(`API ${r.status}`);
-      return r.json();
-    }),
+import axios, { AxiosInstance } from 'axios';
+
+const API_BASE_URL = import.meta.env.VITE_API_BASE_URL || 'http://localhost:3001';
+
+const api: AxiosInstance = axios.create({
+  baseURL: API_BASE_URL,
+  timeout: 10000,
+  headers: {
+    'Content-Type': 'application/json',
+  },
+});
+
+/**
+ * The configured base URL of the Octraban indexer backend.
+ * Defaults to http://localhost:3001 (see README for the frontend/backend contract).
+ */
+export const getApiBaseUrl = (): string => API_BASE_URL;
+
+/**
+ * Lightweight connection check against the backend health endpoint.
+ * Returns true when the indexer is reachable, false otherwise.
+ * Never throws so callers can render a non-blocking banner.
+ */
+export const checkBackendHealth = async (): Promise<boolean> => {
+  try {
+    const response = await api.get('/api/health');
+    return response.status >= 200 && response.status < 300;
+  } catch {
+    return false;
+  }
 };
+
+export default api;
diff --git a/src/components/BackendStatusBanner.tsx b/src/components/BackendStatusBanner.tsx
index cfa1078..a821331 100644
--- a/src/components/BackendStatusBanner.tsx
+++ b/src/components/BackendStatusBanner.tsx
@@ -120,14 +120,14 @@ export default function BackendStatusBanner() {
         . Contract data, events, and search results will not load until the
         backend is running. See the{" "}
         <a
-          href="https://github.com/pharuq411/octraban_frontend#-how-it-fits-together"
+          href="https://github.com/pharuq411/octraban_backend"
           target="_blank"
           rel="noreferrer noopener"
           style={{ color: "var(--accent, #58a6ff)" }}
         >
-          setup guide
+          backend repository
         </a>{" "}
-        for instructions.
+        for setup instructions.
       </div>
 
       {/* Dismiss */}