NRB Forex

NRB typically publishes once daily (~09:00–10:00 NST) and may revise
slightly during the business day. This client:

• Past NST dates → cache forever (immutable)
• Today / future → soft TTL of 2 hours (catch revisions, avoid NRB spam)
• Prefer one long-lived client (or Redis) — not a new client per request
• Browser demos: hit a proxy with Cache-Control; do not call NRB from the browser

import {
  createNrbForexClient,
  MemoryForexCache,
  type ForexCache,
} from "@itzsa/nrb-forex";

// Long-lived Node process — in-memory is enough.
// Historical days: cached forever. Today (NST): soft-refresh every 2h
// so rare midday NRB revisions are picked up.
const client = createNrbForexClient({
  cache: new MemoryForexCache(),
  fallbackToPreviousDay: true, // weekends / pre-publish morning
});

await client.getRatesForDate(); // Nepal "today"

// Serverless / multi-instance — use Redis (or similar) so cache is shared.
const redisCache: ForexCache = {
  async get(key) { /* redis.get + JSON.parse */ },
  async set(key, value, ttlMs) { /* redis.set with EX */ },
  async has(key) { /* … */ },
};

const shared = createNrbForexClient({ cache: redisCache });

GET https://www.nrb.org.np/api/forex/v1/rates?page=1&per_page=100&from=2026-07-17&to=2026-07-17

{
  "status": { "code": 200 },
  "errors": { "validation": null },
  "params": {
    "from": "2026-07-17",
    "to": "2026-07-17",
    "per_page": 100,
    "page": 1
  },
  "data": {
    "payload": [
      {
        "date": "2026-07-17",
        "published_on": "2026-07-17 00:00:17",
        "modified_on": "2026-07-17 00:00:17",
        "rates": [
          {
            "currency": { "iso3": "USD", "name": "U.S. Dollar", "unit": 1 },
            "buy": 133.45,
            "sell": 134.05
          },
          {
            "currency": { "iso3": "INR", "name": "Indian Rupee", "unit": 100 },
            "buy": 160.0,
            "sell": 160.15
          }
        ]
      }
    ]
  },
  "pagination": {
    "page": 1,
    "pages": 1,
    "per_page": 100,
    "total": 1,
    "links": { "prev": null, "next": null }
  }
}

{
  "status": { "code": 400 },
  "errors": {
    "validation": {
      "per_page": [
        "Per Page is required",
        "Per Page must be an integer",
        "Per Page must be at least 1",
        "Per Page must be no more than 100"
      ],
      "page": ["Page is required", "Page must be an integer"],
      "from": [
        "From is required",
        "From must be date with format 'Y-m-d'"
      ],
      "to": ["To is required"]
    }
  },
  "params": { "from": "", "to": "", "per_page": "", "page": "" },
  "data": { "payload": null },
  "pagination": {
    "page": null,
    "pages": null,
    "per_page": null,
    "total": null,
    "links": { "prev": null, "next": null }
  }
}