Contact person: Business Client

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Location: Hanover, United States

Budget: Recommended by industry experts

Time to start: As soon as possible

Project description:
"Project Description
We run a high-frequency market-making bot on Kalshi (crypto hourly binary options).
The bot receives a real-time target order book (c.TARGET_ORDER_BOOK) and must create, amend, or cancel resting orders to match it — as fast and reliably as possible.
Your job:
Build a rock-solid, async order placement engine that:

Compares current open orders with the target book
Sends CREATE / AMEND / CANCEL requests via aiohttp
Persists order state (in-memory + JSON via safe_write_json)
Respects Kalshi rate limits:
Max 20 write operations per second
Max 1 batch cancel per second
Max 20 order IDs per batch

Uses batched DELETE when ADVANCED_API = True
Handles 404s, timeouts, and race conditions without spam or KeyError

This is low-latency, high-stakes code — every failed cancel or repeated request costs money.

Tech Stack

Python 3.9 (async/await)
aiohttp + signed headers
Kalshi REST API (/portfolio/orders, /batched)
Global config ([login to view URL])
In-memory state (c.ORDER_TRACKER_STATE)
Disk persistence via safe_write_json


Your Task
Refactor and harden:

[login to view URL] – core placement logic
batch_cancel_orders – rate-limited, batched, fallback support

Deliver:

No repeated cancels ([CANCEL ALREADY GONE])
No KeyError in timeout watcher
Immediate tracker removal on success or 404
Rate limiting: 1 batch/sec, 20 IDs/batch
Clean, debug-rich logging (include full_ticker + order_id)
Full persistence of live orders to JSON


Required Skills

Expert Python 3.9 async/await
Deep experience with race conditions in async systems
Built trading or market-making bots before
Comfortable with rate-limited financial APIs
Kalshi API experience = major plus


To Apply – READ OR BE IGNORED (BOT FILTER)
Only bids answering the question below will be considered.
Question:
What is the title of this page?
[login to view URL]
Put the answer in bold at the top of your proposal, then tell us:

Your experience with async Python + financial APIs
How you’ll prevent repeated cancel attempts
Why removing tracker entries on 404 is critical

No answer = automatic rejection." (client-provided description)