Python API Reference

Axle Client

The main client for interacting with the AXLE API.

Basic Usage

import asyncio
from axle import AxleClient

async def main():
    async with AxleClient() as client:
        result = await client.check(content="import Mathlib\ndef x := 1", environment="lean-4.28.0")
        print(f"Valid: {result.okay}")

asyncio.run(main())

Constructor

AxleClient(
    api_key: str | None = None,          # default: AXLE_API_KEY env var
    url: str | None = None,              # default: AXLE_API_URL env var
    max_concurrency: int | None = None,  # default: AXLE_MAX_CONCURRENCY env var
    base_timeout_seconds: float | None = None,  # default: AXLE_TIMEOUT_SECONDS env var
)

All arguments fall back to their corresponding environment variables if not provided. See Configuration for details.

Error Handling

All errors raise exceptions. Use try/except to handle them:

from axle.exceptions import (
    AxleIsUnavailable,
    AxleRuntimeError,
    AxleInternalError,
    AxleInvalidArgument,
    AxleRateLimitedError,
    AxleForbiddenError,
    AxleNotFoundError,
    AxleConflictError,
)

try:
    result = await axle.check(content=code, environment="lean-4.28.0")
except AxleIsUnavailable as e:
    print(f"API unavailable at {e.url}: {e.details}")
except AxleInvalidArgument as e:
    print(f"Invalid request: {e}")
except AxleInternalError as e:
    print(f"Server error: {e}")
except AxleRuntimeError as e:
    print(f"Operation failed: {e}")

Exception	HTTP Status	Cause	Action
AxleIsUnavailable	503	Cannot reach API server (connection refused, DNS failure, service unavailable, service upgrade)	Automatically retried; check network if persistent
AxleRateLimitedError	429	Too many requests	Automatically retried with backoff
AxleInvalidArgument	400	Malformed request (missing parameters, invalid arguments)	Fix the request
AxleForbiddenError	403	Access denied	Check credentials/permissions
AxleNotFoundError	404	Resource not found	Check the endpoint or resource ID
AxleConflictError	409	Request conflicts with current state	Resolve the conflict
AxleInternalError	500	Server bug	Report it
AxleRuntimeError	—	Operation couldn't complete (timeout, resource limits)	Retry or adjust parameters

Automatic Retries

The client automatically retries transient errors with exponential backoff:

• AxleIsUnavailable (503, connection errors)
• AxleRateLimitedError (429)

Non-retryable errors like AxleInternalError (500) and client errors (4xx) are raised immediately.

To catch all API errors at once, use the base class AxleApiError.