# 404: Not Found

A `404` can mean different things depending on endpoint and request context.

This guide is intentionally detailed and will be built out case by case.

## Case 1: Market Closed on Requested Date

One of the most helpful `404` responses is:

```json
{
  "s": "no_data",
  "errmsg": "Market closed on this date."
}
```

What this means:

- Your symbol/request shape is valid.
- The requested date is not a trading day for that market/session.
- The API returns `no_data` to explain that the date context is invalid for quote/candle retrieval.

What to do:

1. Check if the requested date is a weekend or market holiday.
2. Retry with the nearest trading day.
3. If using automated date logic, add trading-calendar validation before requesting.

## Case 2: Valid OCC Symbol Format, But Contract Does Not Exist

Another common `404` response is:

```json
{
  "s": "error",
  "errmsg": "No option found. No option was found for this strike and expiration."
}
```

What this means:

- The option symbol format is valid OCC symbology.
- But no real option contract exists for that strike/expiration combination.
- This is not a malformed-parameter case (`400`) and not a date-only no-data case.
- The API treats this as a non-existent contract and returns `404`.

How this differs from other errors:

1. `400 invalid option symbol`: OCC format itself is malformed.
2. `404 no_data` market/date cases: symbol can exist, but no data for that date/session.
3. This case: OCC format is valid, but the contract likely never existed.

What to do:

1. Verify strike and expiration against available contracts for the underlying.
2. Use `options/chain` or `options/expirations` to confirm the contract exists.
3. Use `options/lookup` to avoid manually constructing symbols.

## Case 3: Valid Symbol, But Requested Time Has No Available Data

Another common `404`/`no_data` response is:

```json
{
  "s": "no_data",
  "nextTime": null,
  "prevTime": null
}
```

What this means:

- The symbol/request can be valid.
- But there is no data available around the requested time in either direction.
- This can happen for both stocks and options.

Common reasons:

1. Requested date is outside available historical coverage for that symbol/endpoint.
2. Valid option contract was requested before it began quoting.
3. Requested window has no recorded quotes/candles and there is no adjacent data to return.

Important context:

- This is not necessarily customer error.
- It can represent a legitimate \"data does not exist in this time region\" condition.

What to do:

1. Move the request window forward in time and retry.
2. For options, confirm the contract had started trading by that date.
3. Use nearby date probes to find first/last available data for the symbol.