flex-api (Python)

Client for the Flex on the Job tenant API. Standard library only, Python 3.9+.

from flex_api import FlexClient, FlexApiError, SANDBOX_URL

flex = FlexClient(api_key="flx_live_...")          # Settings -> Integrations -> API Keys
# flex = FlexClient("flx_live_YLJG6oxA6hOiJTT7ziyAOFs8nJAJfbRE", base_url=SANDBOX_URL)  # public read-only demo

for item in flex.paginate("/api/v1/items", search="filter"):
    print(item["name"], item["onHand"])

# Writes get an Idempotency-Key automatically (kept across retries).
flex.post("/api/v1/items/stock/batch", {"operations": [
    {"action": "Adjust", "itemId": 12, "locationId": 3, "delta": -2, "reason": "Cycle count"},
    {"action": "Move", "itemId": 12, "fromLocationId": 3, "toLocationId": 4, "quantity": 1},
]})

try:
    flex.post("/api/v1/purchase-orders", {"receivingLocationId": 1, "lines": [{"itemId": 999, "quantityOrdered": 1}]})
except FlexApiError as e:
    print(e.status, e.detail, e.errors)   # 422 ... {'lines[0].itemId': [...]}

What the client does for you:

• Authorization: Bearer on every request.
• An Idempotency-Key on every POST/PUT/PATCH/DELETE (pass idempotency_key= to choose your own), reused if the request is retried, so a retry is never applied twice.
• Retries 429 and 503 (default 3 times), waiting Retry-After (seconds or an HTTP date), and a 409 "still being processed" while an earlier attempt with the same key is running.
• flex.last_response_headers holds the last response's headers: send its etag back as if_match= on put() / patch() to refuse an update if the record changed in between (412).
• paginate(path, **query) follows nextCursor across pages.
• Errors raise FlexApiError with the RFC 7807 problem: status, detail, and errors per field.

Paths, parameters and bodies are exactly those of the OpenAPI document at https://app.flexonthejob.com/openapi/v1.json (browsable at /docs). Tests: python -m unittest discover -s tests.

Examples in examples/: cycle_count.py, invoice_completed_jobs.py (--finalize also marks the drafts sent), receive_delivery.py and reorder_low_stock.py. They talk to the sandbox unless you set FLEX_BASE_URL=https://app.flexonthejob.com. The last three preview their change and write only after --apply, --yes or an interactive yes. The Flex MCP server (/mcp) offers the same tasks as prompts (cycle_count, invoice_completed_jobs, receive_delivery, reorder_below_minimum).

License

Proprietary — Copyright (c) 2026 Flex Services, LLC. All rights reserved. Licensed for use in your applications to access the Flex on the Job API; you may not copy, modify, redistribute, or reverse-engineer it. See the LICENSE file for the full terms.