> For the complete documentation index, see [llms.txt](https://docs.novamp.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.novamp.io/developers/errors.md).

# Errors & Rate Limits

The Novamp Public Data API uses standard HTTP status codes and a simple, predictable rate-limit model. It's a read plane, so there are no signed decisions or idempotency keys to manage — just clean GETs.

> **Switch on the HTTP status code. Back off on `429` using `Retry-After`.**

{% hint style="info" %}
Because the data API is read-only, errors are straightforward: a bad or wrong-chain lookup is a `404`, and too many requests is a `429`. There is nothing to "fail closed" on — retries are always safe.
{% endhint %}

## Status codes

| Status | Meaning                              | Your action                      |
| ------ | ------------------------------------ | -------------------------------- |
| `200`  | Success                              | Parse the JSON body              |
| `400`  | Malformed request (bad query params) | Fix the request                  |
| `404`  | Unknown token, or wrong-chain lookup | Check the `chainId`/address pair |
| `429`  | Rate limited                         | Back off using `Retry-After`     |
| `5xx`  | Transient server/indexer error       | Retry with backoff               |

The most common surprise is a `404` from a chain-scoped read: `/api/tokens/:chainId/:address` only resolves a token whose `chainId` matches the indexer serving it. Querying an Ethereum token (`1`) against the BNB origin (`56`) returns `404`. Prefer the branded host so routing is handled for you — see [Environments](/developers/environments.md).

## Response shape

Successful list endpoints return a consistent envelope:

```json
{
  "tokens": [],
  "count": 0,
  "limit": 100,
  "offset": 0,
  "ethUsd": { "rate": "3200.00", "source": "chainlink", "asOf": "2026-07-21T00:00:00Z" }
}
```

* Money values are **string decimals** — parse them as decimals, not floats.
* Unknown values are `null`, never omitted.

## Rate limits

* **Per-IP token bucket** — roughly **10 req/sec sustained** with bursts up to \~120.
* Over-limit requests return `429` with a `Retry-After` header (seconds).
* `/health` and the logo proxy are exempt.

```ts
async function getJson<T>(url: string, max = 3): Promise<T> {
  for (let attempt = 0; ; attempt++) {
    const res = await fetch(url);
    if (res.ok) return (await res.json()) as T;
    const retryable = res.status === 429 || (res.status >= 500 && res.status < 600);
    if (!retryable || attempt >= max) {
      throw new Error(`request failed: ${res.status}`);
    }
    const retryAfter = Number(res.headers.get("retry-after")) || 2 ** attempt;
    await new Promise((r) => setTimeout(r, retryAfter * 1000));
  }
}
```

## Pagination & caching

* **Pagination:** `?limit=` (default 100, max 500), `?offset=`.
* **CORS:** `Access-Control-Allow-Origin: *` on all public GETs.
* **Caching:** token endpoints `max-age=20`; DEX adapter `max-age=5`; logos immutable (\~1 year). Respect these to stay well under the rate limit.

## Continue exploring

* [🧑‍💻 Developer Overview](/developers/overview.md)
* [🧩 Integration Examples](/developers/integration-examples.md)
* [📡 Public Data API](/developers/public-api.md)
* [🛡️ Identity Protection](/developers/identity-protection.md)


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