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Fix Protocol MCP

Community Finance and payments

Parse, validate, build and explain FIX protocol trading messages offline, using a bundled FIX 4.4 field dictionary.

Source code Documentation

Install

The installation steps are in the documentation below. Documentation

Documentation

From the project's README on GitHub, refreshed weekly. Links open on GitHub.

Contents
  1. fix-protocol-mcp
  2. Tools
  3. Install
  4. Examples
  5. Coverage
  6. Development
  7. License

fix-protocol-mcp

MCP server for parsing, validating, building, and explaining FIX protocol messages - the tag=value format used for orders and executions across equities, FX, and fixed-income trading.

Runs fully offline. Parsing, validation (BodyLength/CheckSum included), message construction, and the bundled FIX 4.4 field dictionary are all self-contained, no external API or network calls.

Tools

ToolWhat it does
parse_fix_messageDecode a raw FIX string into tag, field name, value, and enum meaning. Accepts SOH-, `\-, or^`-delimited input.
validate_fix_messageCheck field ordering, the standard header, BodyLength(9) and CheckSum(10) against computed values, and required/conditional fields per message type. Returns errors and warnings.
build_fix_messageConstruct a valid FIX message from field inputs. Accepts tag numbers or field names, and enum codes or labels ("Side": "Buy"). BeginString, BodyLength, and CheckSum are computed automatically.
explain_fix_tagLook up a tag's field name, data type, and enumerated values.

Install

pip install .

This installs the fix-protocol-mcp console script (stdio MCP server).

MCP client config
{
  "mcpServers": {
    "fix-protocol": {
      "command": "fix-protocol-mcp"
    }
  }
}

Running from source instead of installing:

{
  "mcpServers": {
    "fix-protocol": {
      "command": "python",
      "args": ["-m", "fix_protocol_mcp.server"],
      "env": { "PYTHONPATH": "src" }
    }
  }
}

Examples

Parse a Logon message:

parse_fix_message("8=FIX.4.2|9=65|35=A|...|98=0|108=30|10=062|")
-> msg_type "A" (Logon), 10 fields, each decoded to name + value + enum meaning

Validate, catching a bad checksum:

validate_fix_message("8=FIX.4.2|9=65|35=A|...|10=000|")
-> { "valid": false, "checksum": {"present":"000","computed":"062","ok":false},
     "errors": ["CheckSum(10)=000 does not match computed checksum 062."] }

Build an order from field names:

build_fix_message(
  msg_type="NewOrderSingle",
  fields={"Symbol":"AAPL","Side":"Buy","OrderQty":100,
          "OrdType":"Limit","Price":"150.25","ClOrdID":"A1"})
-> 8=FIX.4.4|9=113|35=D|49=SENDER|56=TARGET|34=1|52=...|11=A1|38=100|
   40=2|44=150.25|54=1|55=AAPL|60=...|10=061|   (valid: true)

Explain a tag:

explain_fix_tag(40)
-> { "name": "OrdType", "type": "CHAR",
     "values": [{"value":"1","meaning":"Market"}, {"value":"2","meaning":"Limit"}, ...] }

Coverage

The dictionary covers session-level messages and the order/execution workflow (Logon, Heartbeat, TestRequest, ResendRequest, Reject, SequenceReset, Logout, NewOrderSingle, OrderCancelRequest, OrderCancelReplaceRequest, ExecutionReport, OrderCancelReject), which accounts for most real FIX traffic. It's a curated subset rather than the full FIX repository - unrecognised tags and enum values surface as warnings, not hard failures.

Development

pip install -e ".[dev]"
pytest

server.py is a thin MCP wrapper around the core modules (parser, validator, builder, dictionary, wire), which have no dependency on the MCP SDK and can be used as a plain library:

from fix_protocol_mcp import parse, validate, build, describe_tag

License

MIT - see LICENSE.

Frequently asked questions

What is Fix Protocol MCP?

Parse, validate, build and explain FIX protocol trading messages offline, using a bundled FIX 4.4 field dictionary.

How do I install Fix Protocol MCP?

Follow the installation steps in its documentation, shown on this page and in its repository.

Is Fix Protocol MCP open source?

Yes. Its code is on GitHub under the MIT license.

Who maintains Fix Protocol MCP?

It is published by slenderongithub. AI.tn lists it but does not maintain or endorse it.

From the community awesome-mcp-servers lists and the project's GitHub repository. Listing is not an endorsement: review a server's code and permissions before giving it access to your data.