Exceptions

The Python client raises a single exception type for every failure: Backtest360Error. It carries structured fields so you can branch on the cause rather than parse messages.

`backtest360.client.Backtest360Error`

Bases: Exception

Raised on any non-2xx response from the Backtest360 API.

Parameters:

Name	Type	Description	Default
`message`	`str`	Human-readable description of the error.	required
`status`	`int`	HTTP status code returned by the engine (0 for client-side errors raised before any request is sent, e.g. invalid inputs or missing config).	required
`code`	`str \| None`	Machine-readable error code (e.g. `CLIENT_NO_API_KEY`).	`None`
`body`	`dict[str, Any] \| str \| None`	Parsed response body (dict) or raw text if JSON parsing failed.	`None`
`request_id`	`str \| None`	Value of the `X-Request-ID` response header, if present. Quote it when reporting server errors — it joins the failure to the engine's logs.	`None`
`retry_after`	`float \| None`	Seconds to wait before retrying, parsed from the `Retry-After` response header. Set on capacity responses — 429 (quota or concurrency exhausted) and 503 (engine at capacity, retry with backoff). `None` when the header is absent. A 504 means the run exceeded the engine's compute time limit: reduce the date range or strategy complexity rather than retrying.	`None`

Example

import time try: ... result = client.backtest(strategy, df) ... except Backtest360Error as e: ... if e.status == 401: ... print("Invalid API key") ... elif e.status in (429, 503) and e.retry_after: ... time.sleep(e.retry_after) # then retry ... else: ... raise

Fields

Field	Type	Meaning
`status`	`int`	HTTP status from the engine, or `0` for errors the client raises before a request is sent.
`code`	`str \\| None`	Stable machine-readable code (see the tables below).
`body`	`dict \\| str \\| None`	The engine's response body, when present — useful for validation details.
`request_id`	`str \\| None`	Correlates the failure with an engine-side log entry.
`retry_after`	`float \\| None`	Seconds to wait before retrying, set on throttling responses.

Branch on code for programmatic handling and fall back to status for coarse categories. See Handle errors for retry patterns.

Engine error codes

Returned by the engine with a non-zero HTTP status.

Code	Status	When
`AUTH_MISSING`	401	No `X-API-Key` header was sent.
`AUTH_INVALID`	401	The key is unknown or has been revoked.
`AUTH_EXPIRED`	401	The key has passed its expiry date.
`TENANT_SUSPENDED`	403	The account is suspended.
`SCOPE_DENIED`	403	The key lacks a scope the request requires.
`PLAN_UPGRADE_REQUIRED`	403	A paid-only feature was requested on a free key.
`BAR_LIMIT_EXCEEDED`	413	The request exceeds the key's bar cap.
`QUOTA_EXCEEDED`	429	A per-minute or per-day quota was hit. `retry_after` is set.
`CONCURRENCY_EXCEEDED`	429	Too many requests are in flight for the key.
`RATE_LIMITED`	429	An upstream data provider throttled the request (distinct from quota).
`INVALID_SYMBOL`	400	The requested symbol is unknown.
`INVALID_LEG_COUNT`	400	The number of legs falls outside the supported 1–20 range.
`INVALID_PARAMETERS`	400 / 422	A request parameter failed validation.
`DATA_ERROR`	400	The data provider returned an error for the request.
`PROVIDER_UNAVAILABLE`	502	A data provider is unavailable.
`ENGINE_BUSY`	503	Compute capacity is exhausted.
`COMPUTE_TIMEOUT`	504	The engine timed out while computing.

Client-side error codes

Raised by the client itself, before or after the request, always with status 0.

Code	Status	Meaning
`CLIENT_NO_API_KEY`	0	No API key was provided and none was found in the environment.
`CLIENT_PATH_FORBIDDEN`	0	A request targeted a path outside `/api/`.
`CLIENT_TEMPLATE_NOT_FOUND`	0	A named strategy template does not exist.
`CLIENT_INVALID_PAYLOAD`	0	A request payload failed client-side validation.
`CLIENT_INVALID_OHLCV`	0	The supplied OHLCV frame is missing columns, misindexed, or otherwise invalid.
`CLIENT_INVALID_SIGNALS`	0	The supplied signal series is invalid.
`CLIENT_INVALID_STRATEGY`	0	The strategy object failed client-side validation.
`CLIENT_MALFORMED_RESPONSE`	0	The engine returned a response the client could not parse.

Strategy validation errors

Strategy validation does not collapse to a single code. When a strategy document fails validation, the engine returns a structured report and the client surfaces it in body:

{
  "valid": false,
  "errors": [
    {
      "code": "UNKNOWN_INDICATOR",
      "location": "legs[0].strategy.rules[0]",
      "message": "Indicator 'rsii' is not recognized.",
      "context": {"indicator": "rsii"}
    }
  ]
}

Each item names a specific problem — for example UNKNOWN_INDICATOR, UNKNOWN_FIELD, or INVALID_INDICATOR_PARAMS — with the location in the document that caused it. Use validate_strategy() to obtain this report without running a backtest.