Kyro

Kyro is an async Python client library for the Kalshi REST API.

It uses aiohttp for async HTTP requests and Pydantic for request and response validation. The library mirrors the API surface closely and exposes a typed, low-level interface.

API areas are grouped into:

exchange
markets
events
search
orders
portfolio

Errors are surfaced as explicit exception types: KyroError (base), KyroHTTPError, KyroTimeoutError, KyroConnectionError, KyroValidationError — with status codes, response bodies, and error codes attached so you can debug and branch without re-calling the API.

Requirements

Python ≥ 3.10 (3.10–3.12 supported)
aiohttp ≥ 3.9
pydantic ≥ 2

Install

From PyPI:

pip install kyro

From the repo (development / unreleased):

pip install -e .

Authentication (request signing, .env loading) is included in the core package. See Authentication.

On Homebrew Python (macOS) and other PEP 668 setups, use a virtual environment first:

python3 -m venv .venv && source .venv/bin/activate
pip install kyro   # or: pip install -e .  for development

Configuration

from kyro import KyroConfig, config_from_env

# Production (default). Despite "elections" in the host, this serves all Kalshi markets.
cfg = KyroConfig(base_url="https://api.elections.kalshi.com/trade-api/v2")

# Demo
cfg = KyroConfig(base_url="https://demo-api.kalshi.co/trade-api/v2")

# From environment (base URL and optional auth). See env vars below.
cfg = config_from_env()                    # production by default
cfg = config_from_env(default_demo=True)   # demo when KALSHI_* not set

# Timeouts and headers
cfg = KyroConfig(
    request_timeout=15.0,
    connect_timeout=5.0,
    default_headers={"User-Agent": "MyApp/1.0"},
)

Environment variables (for config_from_env()): put these in a .env in the current directory (copy from .env.example) or export them. .env is loaded automatically when config_from_env() is used.

Variable	Description
`KALSHI_BASE_URL`	Override API base URL
`KALSHI_DEMO=1`	Use demo base URL
`KALSHI_PRODUCTION=1`	Use production base URL
`KALSHI_ACCESS_KEY` or `KALSHI_ACCESS_KEY_ID`	API key ID for request signing
`KALSHI_PRIVATE_KEY`	PEM string (use `\n` for newlines in env)
`KALSHI_PRIVATE_KEY_PATH`	Path to `.key` or `.pem` file

Authentication

Kalshi uses RSA-PSS request signing. Each authenticated request must include:

KALSHI-ACCESS-KEY — your API key ID
KALSHI-ACCESS-TIMESTAMP — Unix milliseconds
KALSHI-ACCESS-SIGNATURE — base64‑encoded signature of timestamp + method + path (path without query string), signed with your private key.

Kyro supports three ways to supply auth; config_from_env() is the usual choice.

1. `config_from_env()` (recommended)

Set keys in .env or the environment (.env is loaded automatically by config_from_env()). In .env (or export):

KALSHI_ACCESS_KEY=your-key-id
KALSHI_PRIVATE_KEY_PATH=/path/to/your.pem
# or inline PEM (use \n for newlines):
# KALSHI_PRIVATE_KEY="-----BEGIN PRIVATE KEY-----\n...\n-----END PRIVATE KEY-----"

Then:

from kyro import config_from_env, RestClient

cfg = config_from_env()  # or config_from_env(default_demo=True)
async with RestClient(cfg) as client:
    bal = await client.get("/portfolio/balance")  # auth added automatically

cryptography and python-dotenv are core dependencies; signing and .env loading work with a plain pip install kyro.
If both KALSHI_ACCESS_KEY (or KALSHI_ACCESS_KEY_ID) and a private key (from KALSHI_PRIVATE_KEY or KALSHI_PRIVATE_KEY_PATH) are set, Kyro builds an auth signer and attaches the three headers to every request. No extra code.
KALSHI_PRIVATE_KEY_PATH can be relative to the current working directory (e.g. kal_key.pem or .kalshi/kal_key.pem).
For inline PEM in .env, use \n for newlines: KALSHI_PRIVATE_KEY="-----BEGIN PRIVATE KEY-----\nMIIE...\n-----END PRIVATE KEY-----".

2. Static `auth_headers` (manual or pre-signed)

If you generate the three headers yourself (e.g. for testing or a custom pipeline):

from kyro import KyroConfig, RestClient

cfg = KyroConfig(
    base_url="https://api.elections.kalshi.com/trade-api/v2",
    auth_headers={
        "KALSHI-ACCESS-KEY": "your-key-id",
        "KALSHI-ACCESS-TIMESTAMP": "1737654321000",
        "KALSHI-ACCESS-SIGNATURE": "base64-signature...",
    },
)
async with RestClient(cfg) as client:
    ...

Caveat: the timestamp must be fresh for each request. Kalshi rejects old timestamps, so static auth_headers are only suitable for short-lived runs or when you refresh them yourself. For normal use, prefer config_from_env() or an auth_signer.

3. Custom `auth_signer` (advanced)

You can pass a callable that returns the auth headers per request:

from kyro import KyroConfig, RestClient

def my_signer(method: str, path: str, body: bytes | None) -> dict[str, str]:
    # path is the full path (e.g. /trade-api/v2/portfolio/balance), no query string.
    # Return {"KALSHI-ACCESS-KEY": "...", "KALSHI-ACCESS-TIMESTAMP": "...", "KALSHI-ACCESS-SIGNATURE": "..."}
    ...

cfg = KyroConfig(base_url="...", auth_signer=my_signer)
async with RestClient(cfg) as client:
    ...

auth_signer overrides auth_headers: if both are set, only the signer is used.
The signer is called on every request with (method, path, body). Kyro sends whatever headers it returns.

Which endpoints require auth

Requires auth	Endpoints
No	`exchange.get_exchange_status`, `get_exchange_announcements`, `get_exchange_schedule`, `get_series_fee_changes`; all of `markets.`, `events.`, and `search.*`
Yes	`exchange.get_user_data_timestamp`; all of `orders.` and `portfolio.`

Without auth, public endpoints work as usual. Auth-required calls return 401 if the headers are missing or invalid.

Getting API keys and keys file

Log in at kalshi.com → Account → API (or API Keys).
Create an API key and download the .pem (private key). Keep the key ID shown there.
Put KALSHI_ACCESS_KEY=<key-id> and KALSHI_PRIVATE_KEY_PATH=/path/to/file.pem in .env, or use KALSHI_PRIVATE_KEY with the PEM string.

Security: Do not commit .env or .pem files. Prefer KALSHI_PRIVATE_KEY_PATH to a file outside the repo; avoid storing the raw PEM in env if you can.

Modular API (exchange, markets, events, search, orders, portfolio)

from kyro import RestClient, KyroConfig
from kyro.rest import exchange, markets, events, search, orders, portfolio

async with RestClient(KyroConfig()) as client:
    # Exchange (no auth except get_user_data_timestamp)
    status = await exchange.get_exchange_status(client)
    await exchange.get_exchange_announcements(client)
    await exchange.get_exchange_schedule(client)
    await exchange.get_series_fee_changes(client, series_ticker="KXBTC")
    await exchange.get_user_data_timestamp(client)  # auth

    # Markets — filters: series_ticker, event_ticker, status, tickers, min/max_*_ts, cursor
    ms = await markets.get_markets(
        client, series_ticker="KXBTC", limit=10, status="open"
    )
    await markets.get_markets(
        client, event_ticker="INXD-25", limit=5, status="open"
    )
    m = await markets.get_market(client, "KXBTC-24JAN15")
    ob = await markets.get_market_orderbook(client, "KXBTC-24JAN15", depth=10)
    trades = await markets.get_trades(
        client,
        ticker="KXBTC-24JAN15",
        limit=50,
        min_ts=1704067200,
        max_ts=1735689600,
    )
    await markets.get_market_candlesticks(
        client,
        "KXBTC-24JAN15",
        series_ticker="KXBTC",
        period_interval=60,
        limit=100,
    )
    await markets.get_live_data(client, "KXBTC-24JAN15")
    await markets.get_multiple_live_data(client, "KXBTC-24JAN15,INXD-25")
    await markets.get_series(client, "KXBTC")
    await markets.get_series_list(client, limit=20)  # cursor= for pagination

    # Events — filters: series_ticker, status, with_nested_markets, with_milestones, min_close_ts
    evs = await events.get_events(
        client,
        limit=20,
        status="open",
        series_ticker="KXBTC",
        with_nested_markets=True,
    )
    ev = await events.get_event(client, "INXD-25", with_nested_markets=True)
    await events.get_event_metadata(client, "INXD-25")
    await events.get_event_candlesticks(
        client, "KXBTC", "INXD-25", period_interval=60, limit=100
    )
    await events.get_multivariate_events(client, limit=10)

    # Search (no auth)
    await search.get_sports_filters(client)
    await search.get_tags_by_categories(client)

    # Orders (auth) — filters: ticker, event_ticker, status, min_ts, max_ts, cursor, subaccount
    ords = await orders.get_orders(
        client, ticker="KXBTC-24JAN15", status="resting", limit=50
    )
    o = await orders.get_order(client, "order-id")
    await orders.create_order(
        client,
        ticker="KXBTC-24JAN15",
        side="yes",
        action="buy",
        count=1,
        yes_price=50,
        time_in_force="good_till_canceled",
    )
    await orders.cancel_order(client, "order-id")
    await orders.amend_order(
        client, "order-id", ticker="KXBTC-24JAN15", side="yes", action="buy", yes_price=55
    )
    await orders.decrease_order(client, "order-id", reduce_by=1)
    await orders.batch_create_orders(
        client,
        [{"ticker": "KXBTC-24JAN15", "side": "yes", "action": "buy", "count": 1, "yes_price": 50}],
    )
    await orders.batch_cancel_orders(client, order_ids=["id1", "id2"])

    # Portfolio (auth) — filters: ticker, event_ticker, min_ts, max_ts, cursor, subaccount
    await portfolio.get_portfolio(client)
    bal = await portfolio.get_balance(client)
    pos = await portfolio.get_positions(
        client, ticker="KXBTC-24JAN15", limit=100
    )
    await portfolio.get_fills(
        client,
        ticker="KXBTC-24JAN15",
        min_ts=1704067200,
        max_ts=1735689600,
        limit=50,
    )
    await portfolio.get_settlements(
        client, event_ticker="INXD-25", limit=50
    )
    await portfolio.get_total_resting_order_value(client)

API Reference

Full request/response docs for every method (exchange, markets, events, search, orders, portfolio):
API_REFERENCE.md

Examples

The examples/ directory has standalone scripts that use kyro. They are not part of the library.

From repo root with kyro installed (venv activated, pip install -e . or .[dev]):

fetch_orderbook_example.py — Fetches an event, a market, and an orderbook; parses the book (best bid/ask, mid, spread). Uses the demo API by default (no keys); production may require auth.
```
python examples/fetch_orderbook_example.py
# production: KALSHI_PRODUCTION=1 in .env, or: KALSHI_PRODUCTION=1 python examples/fetch_orderbook_example.py
```

Error handling

All exceptions inherit from KyroError. Use the specific types to branch on API errors, timeouts, connection failures, or validation (Pydantic) issues:

from kyro import RestClient, KyroConfig
from kyro.rest import markets
from kyro import (
    KyroError,
    KyroHTTPError,
    KyroConnectionError,
    KyroTimeoutError,
    KyroValidationError,
)

async with RestClient(KyroConfig()) as client:
    try:
        await markets.get_market(client, "NONEXISTENT-TICKER")
    except KyroHTTPError as e:
        # e.status, e.response_body, e.error_code — all set from the Kalshi response
        if e.status == 404:
            print("Not found:", e.error_code)
        elif e.status in (401, 403):
            print("Auth failed:", e.response_body)
        else:
            print(e)
    except KyroConnectionError:
        print("Network error (DNS, connection refused, etc.)")
    except KyroTimeoutError as e:
        print("Request timed out", e.timeout)
    except KyroValidationError as e:
        print("Invalid request/response:", e.details)

Example error output

Real tracebacks from a run. Each exception carries the relevant attributes (e.status, e.response_body, e.error_code, e.timeout, e.details)—branch or log right away, no parsing.

KyroHTTPError (4xx/5xx from Kalshi):

Traceback (most recent call last):
  File "app/main.py", line 12, in fetch_market
    m = await markets.get_market(client, "NONEXISTENT-TICKER")
  File "kyro/rest/api/markets.py", line 65, in get_market
    return await client.get(f"/markets/{ticker}")
  File "kyro/rest/client.py", line 134, in _request
    raise KyroHTTPError("Kalshi API error", status=status, response_body=parsed, error_code=err_code)
kyro.exceptions.KyroHTTPError: Kalshi API error: status=404, error_code='MarketNotFound', response_body="{'code': 'MarketNotFound', 'message': 'Market not found'}"

KyroTimeoutError (request exceeded request_timeout):

Traceback (most recent call last):
  File "app/main.py", line 8, in main
    await markets.get_markets(client, limit=100)
  File "kyro/rest/api/markets.py", line 59, in get_markets
    return await client.get("/markets", params=params or None)
  File "kyro/rest/client.py", line 119, in _request
    raise KyroTimeoutError(str(e) or "Request timed out", timeout=30.0) from e
kyro.exceptions.KyroTimeoutError: Request timed out

KyroConnectionError (DNS, connection refused, etc.):

Traceback (most recent call last):
  File "app/main.py", line 7, in main
    await exchange.get_exchange_status(client)
  File "kyro/rest/api/exchange.py", line 19, in get_exchange_status
    return await client.get("/exchange/status")
  File "kyro/rest/client.py", line 130, in _request
    raise KyroConnectionError(str(e)) from e
kyro.exceptions.KyroConnectionError: Cannot connect to host demo-api.kalshi.co:443 ssl:True [Connection refused]

KyroValidationError (Pydantic schema mismatch, invalid JSON, or bad request body):

Traceback (most recent call last):
  File "app/main.py", line 9, in main
    m = await client.get("/markets/KXBTC", response_model=Market)
  File "kyro/rest/client.py", line 139, in _request
    return loads_model(raw, response_model)
  File "kyro/_serialization.py", line 110, in loads_model
    raise KyroValidationError(f"Validation failed for {model.__name__}: {e}", details=e.errors()) from e
kyro.exceptions.KyroValidationError: Validation failed for Market: 1 validation error for Market
ticker
  Field required [type=missing, input_value={}, input_type=dict]

Project layout

kyro/
├── src/kyro/
│   ├── __init__.py
│   ├── _auth.py           # config_from_env, request signing
│   ├── _config.py
│   ├── _session.py
│   ├── _serialization.py
│   ├── _version.py
│   ├── exceptions.py      # KyroError, KyroHTTPError, KyroTimeoutError, KyroConnectionError, KyroValidationError
│   └── rest/
│       ├── __init__.py    # RestClient, exchange, markets, events, search, orders, portfolio
│       ├── client.py
│       └── api/
│           ├── exchange.py
│           ├── markets.py
│           ├── events.py
│           ├── search.py
│           ├── orders.py
│           └── portfolio.py
├── benchmarks/            # pytest-benchmark: serialization, REST client vs local mock
│   ├── conftest.py        # bench_config, mock server fixture
│   ├── mock_server.py     # Kalshi-like mock for benchmarks
│   ├── bench_serialization.py
│   └── bench_rest_client.py
├── examples/
│   ├── README.md
│   └── fetch_orderbook_example.py
├── scripts/
│   └── live_api_smoke.py  # smoke test every endpoint against live API
├── tests/
├── pyproject.toml
├── README.md
├── API_REFERENCE.md       # Request/response docs for every modular method
└── TESTING.md

Development

Create a venv, install with dev extras, then run tests (required on Homebrew Python; see PEP 668):

python3 -m venv .venv
source .venv/bin/activate   # Windows: .venv\Scripts\activate
pip install -e ".[dev]"     # install only; does not run tests
ruff check .                # lint
black --check .             # format check (black . to fix)
pytest tests/ -v            # run tests

Tests: See TESTING.md. Quick runs (venv activated, .[dev] already installed):

pytest tests/ -v
pytest tests/ -v --cov=kyro --cov-report=term-missing

Benchmarks (serialization + REST client vs a local mock Kalshi server; no live API or auth):

pip install -e ".[dev,bench]"
pytest benchmarks/ -v --benchmark-only

See benchmarks/README.md for the mock server and options.

Live API smoke (every endpoint against the real Kalshi API): python scripts/live_api_smoke.py — see TESTING.md.

If pip install -e ".[dev]" fails with externally-managed-environment, create and activate a venv first; do not use --break-system-packages.

⚠️ Disclaimer ⚠️

The author accepts no responsibility for any use of this software. Kyro is provided as-is. You must adhere to all Kalshi API rules and terms. When trading or using live funds, use caution and understand the risks. Prefer the demo environment for testing.

License

MIT

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Kyro

Requirements

Install

Configuration

Authentication

1. `config_from_env()` (recommended)

2. Static `auth_headers` (manual or pre-signed)

3. Custom `auth_signer` (advanced)

Which endpoints require auth

Getting API keys and keys file

Modular API (exchange, markets, events, search, orders, portfolio)

API Reference

Examples

Error handling

Example error output

Project layout

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.github/workflows		.github/workflows
assets		assets
benchmarks		benchmarks
examples		examples
scripts		scripts
src/kyro		src/kyro
tests		tests
.env.example		.env.example
.gitignore		.gitignore
API_REFERENCE.md		API_REFERENCE.md
DESIGN_CHECKLIST.md		DESIGN_CHECKLIST.md
LICENSE.md		LICENSE.md
README.md		README.md
TESTING.md		TESTING.md
pyproject.toml		pyproject.toml

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Kyro

Requirements

Install

Configuration

Authentication

1. config_from_env() (recommended)

2. Static auth_headers (manual or pre-signed)

3. Custom auth_signer (advanced)

Which endpoints require auth

Getting API keys and keys file

Modular API (exchange, markets, events, search, orders, portfolio)

API Reference

Examples

Error handling

Example error output

Project layout

Development

⚠️ Disclaimer ⚠️

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1. `config_from_env()` (recommended)

2. Static `auth_headers` (manual or pre-signed)

3. Custom `auth_signer` (advanced)

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