langchain-unirate

LangChain integration for the UniRate API — drop-in currency-exchange tooling for LangChain agents and chains.

UniRate provides 593+ fiat, crypto, and commodity exchange rates. Latest rates and conversions are available on the free tier; historical and time-series endpoints require a Pro plan.

Why this package

There's no first-class FX tool in core LangChain — most tutorials show users hand-rolling one against exchangerate-api.com or AlphaVantage. This package gives you a typed, tested wrapper plus a ready-to-use BaseTool that an agent can call directly via tool-calling.

Install

pip install langchain-unirate

Quick start

import os

os.environ["UNIRATE_API_KEY"] = "..."  # https://unirateapi.com

from langchain_unirate import UniRateAPIWrapper, UniRateExchangeTool

wrapper = UniRateAPIWrapper()

# Direct API
print(wrapper.convert("USD", "EUR", amount=100))    # 92.5
print(wrapper.get_rate("USD", "GBP"))               # 0.79
print(wrapper.get_supported_currencies()[:5])

# As an agent tool
tool = UniRateExchangeTool(api_wrapper=wrapper)
tool.invoke({"from_currency": "USD", "to_currency": "EUR", "amount": 100})
# -> "100 USD = 92.5 EUR (UniRate latest rate)"

Use with an agent

from langchain.chat_models import init_chat_model
from langgraph.prebuilt import create_react_agent

from langchain_unirate import UniRateAPIWrapper, UniRateExchangeTool

tool = UniRateExchangeTool(api_wrapper=UniRateAPIWrapper())
agent = create_react_agent(init_chat_model("openai:gpt-4o-mini"), tools=[tool])

agent.invoke({"messages": [("user", "How many euros is 250 dollars right now?")]})

API

UniRateAPIWrapper

UniRateExchangeTool

BaseTool with a structured args_schema over (from_currency, to_currency, amount). Compatible with any LangChain tool-calling pattern: bind_tools(), create_react_agent, ToolNode, etc.

Configuration

Errors map cleanly to ValueError for 401 / 403 / 404 / 429; other non-2xx responses raise requests.HTTPError.

Related UniRate clients

If you want to call the API directly from a non-Python application, there are official clients in Python, Node.js, Go, Rust, Java, Ruby, PHP, .NET, and Swift, as well as an MCP server for Claude Desktop and other MCP hosts.

License

MIT — see LICENSE.