# Expirations (Go SDK)

Get the list of expiration dates that have listed option contracts for an
underlying symbol, returned in Eastern time.

## Making Requests

`Expirations` returns a `[]time.Time` of expiration dates. Two optional,
independent filters narrow the list. Choose the call style that fits your code:

| Method                                  | Return                                     | Description                                                           |
|-----------------------------------------|--------------------------------------------|-----------------------------------------------------------------------|
| **`GetExpirations(symbol, ...opts)`**   | `([]time.Time, error)`                     | Convenience; uses a background context.                               |
| **`Expirations(ctx, symbol, ...opts)`** | `([]time.Time, *response.Response, error)` | Context-aware; also returns the raw response and rate-limit metadata. |

## Expirations

```go
func (s *Service) Expirations(ctx context.Context, symbol string, opts ...ExpirationOption) ([]time.Time, *response.Response, error)
func (s *Service) GetExpirations(symbol string, opts ...ExpirationOption) ([]time.Time, error)
```

`Expirations` fetches the dates on which the underlying has listed option
contracts. The symbol is required; without any options the endpoint returns
every expiration in the chain. The dates are normalized to Eastern time (the
exchange time zone).

### Parameters

- `symbol` (`string`) — the underlying stock symbol (for example `"AAPL"`). Required; an empty string is rejected with a `marketdata.ValidationError` before any request is made.
- Options (independent — may be combined):
  - `options.WithExpirationStrike(strike float64)` — limit the list to expirations that offer a contract at the given strike price. The value must be greater than zero to take effect.
  - `options.WithExpirationDate(d time.Time)` — return the expirations that were available on the given historical date instead of today's list. Only the calendar date is used; a zero time leaves the parameter unset.

### Returns

- `[]time.Time` — the expiration dates, in Eastern time. Empty when there is no data.
- `*response.Response` — the raw response plus rate-limit metadata (context method only).
- `error` — non-nil on a validation failure, transport error, or unexpected API status.

### Notes

- The two options are independent and combine freely (unlike the chain's strike and expiry selectors).
- If the API has no data for the request (HTTP 404), `Expirations` returns a `nil` slice, a response whose `NoData` field is `true`, and a `nil` error.

### Get (simple)

```go
package main

import (
	"fmt"
	"log"

	"github.com/MarketDataApp/sdk-go/v2/marketdata"
)

func main() {
	client, err := marketdata.NewClient(marketdata.WithToken("YOUR_TOKEN"))
	if err != nil {
		log.Fatal(err)
	}
	defer client.Close()

	expirations, err := client.Options.GetExpirations("AAPL")
	if err != nil {
		log.Fatal(err)
	}

	fmt.Println("AAPL option expirations:")
	for _, exp := range expirations {
		fmt.Println(exp.Format("2006-01-02"))
	}
}
```

**Output**

```
AAPL option expirations:
2026-07-17
2026-07-24
2026-07-31
2026-08-21
2026-09-18
2026-12-18
2027-01-15
2027-06-17
...
```

### Context + Response

```go
ctx := context.Background()

expirations, resp, err := client.Options.Expirations(ctx, "AAPL")
if err != nil {
	log.Fatal(err)
}

fmt.Printf("%d expirations\n", len(expirations))
fmt.Printf("Requests remaining: %d\n", resp.RateLimit.Remaining)
```

### With options

```go
ctx := context.Background()

// Only expirations that list a $200 strike, as they stood one week ago.
expirations, _, err := client.Options.Expirations(ctx, "AAPL",
	options.WithExpirationStrike(200),
	options.WithExpirationDate(time.Now().AddDate(0, 0, -7)),
)
if err != nil {
	log.Fatal(err)
}

for _, exp := range expirations {
	fmt.Println(exp.Format("2006-01-02"))
}
```

## Return Value

`Expirations` returns a plain `[]time.Time`. Each element is an expiration
date normalized to Eastern time; call `Format("2006-01-02")` to render the
calendar date. There is no wrapper struct for this endpoint.