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400: Bad Request

Use this page for all 400 BAD REQUEST errors.

A 400 means the request could not be parsed or validated as valid input.

What Usually Causes 400​

  1. URL is constructed incorrectly (path vs query string mixups)
  2. Query parameters are malformed (? / & / key=value issues)
  3. Parameter type or format is invalid (string where number/date is expected)
  4. Parameter value is unsupported or out of range
  5. Option symbol is not valid OCC format
  6. date parameter is used in a current-data request (historical-only usage)

Case 1: URL Construction Problems (Path vs Query)​

Common examples:

  • Putting query parameters in the path segment
  • Missing ? before query parameters
  • Using wrong separators between parameters

Correct structure:

https://api.marketdata.app/<endpoint-path>/?key=value&key2=value2

If you need a step-by-step URL-building guide, use:

Case 2: Invalid Parameter Type/Format/Value​

You can get 400 when a parameter cannot be parsed correctly or violates endpoint rules.

Examples:

  • Sending text where a numeric value is expected
  • Sending a malformed date
  • Sending an unsupported enum/value for a parameter
  • Sending a value outside allowed bounds

Fast check:

  1. Confirm parameter names exactly match the endpoint docs.
  2. Confirm each parameter value type/format is valid.
  3. Remove optional parameters and re-add one at a time.

Case 3: Invalid Option Symbol (OCC)​

You may receive:

{
  "s": "error",
  "errmsg": "Invalid option symbol. Use valid OCC symbology for the option symbol."
}

Meaning: request shape is valid, but optionSymbol is malformed.

For detailed format rules, examples, and validation workflow, use:

Case 4: date Parameter Is Historical-Only​

You may receive:

{
  "s": "error",
  "errmsg": "Invalid date. The date parameter is used for historical queries only."
}

Meaning:

  • Request can be otherwise valid
  • date was used in a current-data context

How to fix:

  1. For current data: omit date
  2. For historical data: provide a past trading date
# Current request (correct): no date parameter
GET https://api.marketdata.app/v1/options/quotes/OPTION_SYMBOL/

# Historical request (correct): includes date
GET https://api.marketdata.app/v1/options/quotes/OPTION_SYMBOL/?date=2025-01-15

400 vs Other Status Codes​

  • 400: request input/format is invalid
  • 401: authentication issue (token missing/invalid)
  • 402: plan/entitlement limit reached
  • 403: forbidden by policy (for example multiple IP addresses)
  • 404: request format is valid, but requested resource was not found

If You Still Get 400​

  1. Log full request URL and all query parameters
  2. Compare request against endpoint docs field-by-field
  3. Re-test with only required parameters
  4. Add optional parameters back one at a time