Security & Testing

fixsim.com

Provides a FIX protocol sandbox for testing order flow, execution reports, and connectivity with a simulated counterparty.

2 endpoints42 known toolsFirst detected September 13, 2026Last detected September 20, 2026

ENDPOINT 1

https://mcp.fixsim.com/mcp

No auth detected

MCP server metadata

Name: fixsim
Version: 0.1.2

Capabilities

loggingtools

Server instructions

FIXSIM is a hosted FIX protocol simulator (fixsim.com). Anyone can test FIX for free with the sandbox_* tools: sandbox_create_session returns host/port/CompIDs the user's FIX engine connects to; no account or key is needed. The fixsim_* tools drive a paying customer's own FIXSIM instances and need their FIXSIM API key (x-api-key header). An instance is a FIX engine holding sessions; the user's trading system connects to a session and FIXSIM plays the counterparty. Start with fixsim_list_instances, then fixsim_list_sessions. 'In' = messages the user's system sent to FIXSIM; 'Out' = messages FIXSIM sent to the user's system. Instance and session names are case-sensitive.

Known tools 21

fixsim_list_orders_out

Orders FIXSIM sent OUT on a session (created with fixsim_send_order).

Inferred read-only

sandbox_get_status

Is the user's FIX engine connected to the sandbox session?

Inferred read-only

fixsim_send_order

Have FIXSIM send a New Order Single (35=D) OUT on a session to the user's system, so they can test how their system handles inbound orders.

Potential side effects

fixsim_list_orders_in

Orders the user's trading system sent INTO FIXSIM on a session (FIXSIM is the counterparty).

Inferred read-only

fixsim_list_executions_in

Execution reports the user's system sent INTO FIXSIM on a session (when FIXSIM is the order sender and the user's system is the executing side).

Inferred read-only

fixsim_act_on_orders

Respond to orders the user's system sent into FIXSIM: acknowledge, fully or partially execute, reject, cancel remaining, expire, done-for-day, restate, or accept/reject a pending cancel/replace.

Potential side effects

sandbox_set_autofill

Turn automatic fills on or off for a sandbox session.

Inferred read-only

fixsim_cancel_order_out

Have FIXSIM send an Order Cancel Request (35=F) for an order it previously sent out with fixsim_send_order.

Potential side effects

fixsim_list_sessions

List the FIX sessions on an instance with their FIX version, CompIDs, acceptor/initiator role, host/port, enabled and logged-in state, and sequence numbers.

Inferred read-only

fixsim_list_executions_out

Execution reports FIXSIM sent OUT on a session (acks, fills, partial fills, rejects, cancels).

Inferred read-only

fixsim_get_session

Get one FIX session's settings and live state (logged in?, sequence numbers, connection details).

Inferred read-only

sandbox_act_on_order

Play the exchange for one order the user sent in: fill (full execution), partial (partial fill), reject, or cancel (cancel the remaining quantity).

Inferred read-only

fixsim_get_order_in

Get one inbound order by ClOrdID (tag 11), including its raw FIX message and audit trail.

Potential side effects

sandbox_get_orders

Working orders the user's engine has sent into the sandbox session: ClOrdID, symbol, side, qty, filled, leaves, price, status.

Inferred read-only

sandbox_get_messages

The FIX message log for a sandbox session, oldest first: logons, heartbeats, orders in, execution reports out, rejects.

Potential side effects

sandbox_create_session

Create a free, anonymous FIX test session on the FIXSIM Developer Sandbox.

Potential side effects

sandbox_end_session

End a sandbox session now instead of waiting for it to expire.

Inferred read-only

fixsim_send_raw_fix

Send one or more raw FIX application messages OUT on a session as given (tag=value pairs separated by | or SOH).

Potential side effects

fixsim_list_instances

List the FIXSIM instances your API key can access.

Inferred read-only

fixsim_list_securities

Securities (symbol, last price, CUSIP, ISIN) configured on an instance.

Inferred read-only

sandbox_get_session

Re-fetch a sandbox session's connection card by id, including whether auto-fill is on and when it expires.

Inferred read-only

CONNECT WITH APPROVAL

Client installation

Review this server and its permissions before adding it. Secret placeholders must be set locally.

Codex

~/.codex/config.toml

[mcp_servers.fixsim]
url = "https://mcp.fixsim.com/mcp"
enabled = true

Claude Code

.mcp.json

{
  "mcpServers": {
    "fixsim": {
      "type": "http",
      "url": "https://mcp.fixsim.com/mcp"
    }
  }
}

Claude Desktop

Settings → Connectors → Add custom connector

Name: fixsim
Remote MCP URL: https://mcp.fixsim.com/mcp

Add this remote URL as a custom connector in Claude Desktop. Availability depends on the user plan and workspace policy.

Cursor

.cursor/mcp.json

{
  "mcpServers": {
    "fixsim": {
      "url": "https://mcp.fixsim.com/mcp"
    }
  }
}

Visual Studio Code

.vscode/mcp.json

Add to Visual Studio Code

{
  "servers": {
    "fixsim": {
      "type": "http",
      "url": "https://mcp.fixsim.com/mcp"
    }
  }
}

Generic MCP

Client-specific MCP configuration

{
  "name": "fixsim",
  "transport": "streamable-http",
  "url": "https://mcp.fixsim.com/mcp"
}

MCP Inspector

Run the official MCP Inspector locally and enter the indexed Streamable HTTP endpoint.

ENDPOINT 2

https://mcp.fixsim.com/mcp/readonly

No auth detected

MCP server metadata

Name: fixsim
Version: 0.1.2

Capabilities

loggingtools

Server instructions

Known tools 21

fixsim_list_orders_out

Orders FIXSIM sent OUT on a session (created with fixsim_send_order).

Inferred read-only

sandbox_get_status

Is the user's FIX engine connected to the sandbox session?

Inferred read-only

fixsim_send_order

Have FIXSIM send a New Order Single (35=D) OUT on a session to the user's system, so they can test how their system handles inbound orders.

Potential side effects

fixsim_list_orders_in

Orders the user's trading system sent INTO FIXSIM on a session (FIXSIM is the counterparty).

Inferred read-only

fixsim_list_executions_in

Execution reports the user's system sent INTO FIXSIM on a session (when FIXSIM is the order sender and the user's system is the executing side).

Inferred read-only

fixsim_act_on_orders

Respond to orders the user's system sent into FIXSIM: acknowledge, fully or partially execute, reject, cancel remaining, expire, done-for-day, restate, or accept/reject a pending cancel/replace.

Potential side effects

sandbox_set_autofill

Turn automatic fills on or off for a sandbox session.

Inferred read-only

fixsim_cancel_order_out

Have FIXSIM send an Order Cancel Request (35=F) for an order it previously sent out with fixsim_send_order.

Potential side effects

fixsim_list_sessions

List the FIX sessions on an instance with their FIX version, CompIDs, acceptor/initiator role, host/port, enabled and logged-in state, and sequence numbers.

Inferred read-only

fixsim_list_executions_out

Execution reports FIXSIM sent OUT on a session (acks, fills, partial fills, rejects, cancels).

Inferred read-only

fixsim_get_session

Get one FIX session's settings and live state (logged in?, sequence numbers, connection details).

Inferred read-only

sandbox_act_on_order

Play the exchange for one order the user sent in: fill (full execution), partial (partial fill), reject, or cancel (cancel the remaining quantity).

Inferred read-only

fixsim_get_order_in

Get one inbound order by ClOrdID (tag 11), including its raw FIX message and audit trail.

Potential side effects

sandbox_get_orders

Working orders the user's engine has sent into the sandbox session: ClOrdID, symbol, side, qty, filled, leaves, price, status.

Inferred read-only

sandbox_get_messages

The FIX message log for a sandbox session, oldest first: logons, heartbeats, orders in, execution reports out, rejects.

Potential side effects

sandbox_create_session

Create a free, anonymous FIX test session on the FIXSIM Developer Sandbox.

Potential side effects

sandbox_end_session

End a sandbox session now instead of waiting for it to expire.

Inferred read-only

fixsim_send_raw_fix

Send one or more raw FIX application messages OUT on a session as given (tag=value pairs separated by | or SOH).

Potential side effects

fixsim_list_instances

List the FIXSIM instances your API key can access.

Inferred read-only

fixsim_list_securities

Securities (symbol, last price, CUSIP, ISIN) configured on an instance.

Inferred read-only

sandbox_get_session

Re-fetch a sandbox session's connection card by id, including whether auto-fill is on and when it expires.

Inferred read-only

CONNECT WITH APPROVAL

Client installation

Review this server and its permissions before adding it. Secret placeholders must be set locally.

Codex

~/.codex/config.toml

[mcp_servers.fixsim]
url = "https://mcp.fixsim.com/mcp/readonly"
enabled = true

Claude Code

.mcp.json

{
  "mcpServers": {
    "fixsim": {
      "type": "http",
      "url": "https://mcp.fixsim.com/mcp/readonly"
    }
  }
}

Claude Desktop

Settings → Connectors → Add custom connector

Name: fixsim
Remote MCP URL: https://mcp.fixsim.com/mcp/readonly

Add this remote URL as a custom connector in Claude Desktop. Availability depends on the user plan and workspace policy.

Cursor

.cursor/mcp.json

{
  "mcpServers": {
    "fixsim": {
      "url": "https://mcp.fixsim.com/mcp/readonly"
    }
  }
}

Visual Studio Code

.vscode/mcp.json

Add to Visual Studio Code

{
  "servers": {
    "fixsim": {
      "type": "http",
      "url": "https://mcp.fixsim.com/mcp/readonly"
    }
  }
}

Generic MCP

Client-specific MCP configuration

{
  "name": "fixsim",
  "transport": "streamable-http",
  "url": "https://mcp.fixsim.com/mcp/readonly"
}

MCP Inspector

Run the official MCP Inspector locally and enter the indexed Streamable HTTP endpoint.

TRUST AND VERIFICATION EVIDENCE

Loading Trust v2 evidence…

Checking the associated registrable domain. The BuiltWith key remains server-side.

Indexed

Evidence is source-attributed and does not guarantee that a third-party server is safe. Risk labels are conservative metadata heuristics.