Errors - Zest Public API

Every non-2xx response from the Zest Public API uses the same envelope. Always parse code first, fall back on detail for human display, and feed errorId into your support ticket if you ever need to escalate.

Envelope shape

{
  "code": "validation_error",
  "detail": "Submitted attributes failed contract validation.",
  "errorId": "1f1a4b3e-7c0e-4ed3-9abe-3cbef1f17c1f",
  "validationErrors": [
    {
      "field": "attributes.shareClasses[0].carryPercent",
      "code": "min_value",
      "message": "carryPercent must be >= 0",
      "value": "-1.0"
    }
  ]
}

Field	Type	Description
`code`	`string`	Top-level error code from the PartnerErrorCode vocabulary.
`detail`	`string`	Human-readable explanation. Safe to show to operator UIs but not to end-users without sanitisation.
`errorId`	`string (UUID)`	Stable per-error UUID. Cite this when contacting support.
`validationErrors`	`array`	Optional. Present on `validation_error` to surface per-field errors. See Validation error codes.

Top-level codes

Code	HTTP	Meaning
`validation_error`	`400`	Submitted payload failed contract validation. Inspect `validationErrors[]`.
`invalid_request`	`400`	Request was syntactically invalid (missing required header, malformed JSON, etc.).
`invalid_token`	`401`	Bearer token missing, malformed, or expired. Mint a fresh access token.
`forbidden`	`403`	Token is valid but the partner application is not provisioned for this resource.
`not_found`	`404`	Resource does not exist or is not visible to the caller.
`conflict`	`409`	Idempotency-Key conflict, terminal-state mutation, or strict-order violation.
`payload_too_large`	`413`	File exceeded the 10 MB upload cap.
`unsupported_media_type`	`415`	Upload content-type not in the allow list (PDF, JPEG, PNG, WEBP).
`internal_error`	`500`	Something broke on Zest’s side. Retry with backoff; cite `errorId` if persistent.
`service_unavailable`	`503`	Transient downstream outage. Retry with exponential backoff.

Validation error codes

Inside the validationErrors[].code field. Every code is stable and machine-actionable.

Code	Meaning
`required`	Required field missing.
`unknown_attribute`	Attribute not declared by the contract template.
`type`	Value is the wrong type (e.g. string where number expected).
`enum`	Value is not in the allowed enum set.
`pattern`	Value did not match the regex constraint.
`max_length`	String exceeded the maximum length.
`min_value`	Number below the minimum.
`max_value`	Number above the maximum.
`format`	Format constraint failed (e.g. ISO date, ISO 4217 currency).
`currency_mismatch`	Multi-currency mismatch within a single object.
`server_supplied`	Field is server-managed and cannot be supplied by partner.
`institutional_not_supported`	Institutional investor type not supported on this template.

Sample envelopes

400 validation_error

{
  "code": "validation_error",
  "detail": "Contract validation failed",
  "errorId": "1f1a4b3e-7c0e-4ed3-9abe-3cbef1f17c1f",
  "validationErrors": [
    {
      "field": "attributes.shareClasses[0].carryPercent",
      "code": "min_value",
      "message": "carryPercent must be >= 0",
      "value": "-1.0"
    }
  ]
}

401 invalid_token

{
  "code": "invalid_token",
  "detail": "Bearer token is expired",
  "errorId": "9f2d83bc-4715-4f99-9c4e-1e5ad23bca03"
}

409 conflict (idempotency)

{
  "code": "conflict",
  "detail": "Idempotency-Key already used with a different request body",
  "errorId": "65bda4f2-0a0c-4e88-9cd0-2c4dec6fe7bb"
}

413 payload_too_large

{
  "code": "payload_too_large",
  "detail": "File exceeds the 10 MB limit",
  "errorId": "c1b0e5da-2ff0-49a4-b76a-db09ad0c33a0"
}

Working with `errorId`

errorId is generated server-side and persisted in our logs. Bake it into your operator dashboards next to every red-flagged event so support can trace incidents in seconds.

​Envelope shape

​Top-level codes

​Validation error codes

​Sample envelopes

​400 validation_error

​401 invalid_token

​409 conflict (idempotency)

​413 payload_too_large

​Working with errorId