FIXSIM is a remote MCP server that gives an AI agent 21 tools, among them fixsim_act_on_orders, fixsim_cancel_order_out, fixsim_get_order_in. It answers at https://mcp.fixsim.com/mcp over streamable HTTP, and it listed its tools to an anonymous client, so no sign-in was needed for that. Our probes reached it 5 of 5 times since 12 September 2026; the last check, on 19 October 2026, succeeded.
Test FIX from Claude, ChatGPT, or Cursor: free sandbox FIX sessions or your own FIXSIM instances.
Description as the publisher wrote it.
| Tool | What it does |
|---|---|
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. FIXSIM emits the matching execution reports o Inputs: instance, session, action, clOrdIds, lastPx, lastQty |
fixsim_cancel_order_out | Have FIXSIM send an Order Cancel Request (35=F) for an order it previously sent out with fixsim_send_order. Inputs: instance, session, clOrdId, newClOrdId, additionalTags, apiKey |
fixsim_get_order_in | Get one inbound order by ClOrdID (tag 11), including its raw FIX message and audit trail. Use this to explain why an order was rejected or what state it is in. Inputs: instance, session, clOrdId, apiKey |
fixsim_get_session | Get one FIX session's settings and live state (logged in?, sequence numbers, connection details). Inputs: instance, session, apiKey |
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). Optionally filter by ExecID (tag 17). Inputs: instance, session, execId, limit, apiKey |
fixsim_list_executions_out | Execution reports FIXSIM sent OUT on a session (acks, fills, partial fills, rejects, cancels). Pass clOrdId to see the full execution history of one order: ExecType, OrdStatus, LastPx/LastQty, CumQty, LeavesQty, AvgPx and the raw FIX. Inputs: instance, session, clOrdId, limit, apiKey |
fixsim_list_instances | List the FIXSIM instances your API key can access. An instance is a hosted FIX engine; each holds one or more FIX sessions. Start here to learn the instance names other tools need. Inputs: apiKey |
fixsim_list_orders_in | Orders the user's trading system sent INTO FIXSIM on a session (FIXSIM is the counterparty). Includes ClOrdID, symbol, side, quantity, remaining quantity, order status and the raw FIX message. Optionally filter by FIX OrdStatus code (tag 39 Inputs: instance, session, orderStatus, limit, apiKey |
fixsim_list_orders_out | Orders FIXSIM sent OUT on a session (created with fixsim_send_order). Pass clOrdId to fetch one. Inputs: instance, session, clOrdId, limit, apiKey |
fixsim_list_securities | Securities (symbol, last price, CUSIP, ISIN) configured on an instance. FIXSIM prices fills from these. Inputs: instance, apiKey |
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. Inputs: instance, apiKey |
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. Follow up with fixsim_list_orders_out and fixsim_list_executions_in to see what came back. Inputs: instance, session, clOrdId, symbol, side, orderQty |
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). FIXSIM supplies the session header fields (BeginString, CompIDs, MsgSeqNum, SendingTime) and the checksum. Use for message type Inputs: instance, session, fixMessages, apiKey |
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). FIXSIM sends the matching execution report back to the user's engine. Inputs: sessionId, clOrdId, action |
sandbox_create_session | Create a free, anonymous FIX test session on the FIXSIM Developer Sandbox. No account or API key needed. Returns the connection card: host, port, the SenderCompID the user must put in tag 49, the TargetCompID for tag 56, BeginString, and th Inputs: fixVersion |
sandbox_end_session | End a sandbox session now instead of waiting for it to expire. Frees the slot for the user's IP. Inputs: sessionId |
sandbox_get_messages | The FIX message log for a sandbox session, oldest first: logons, heartbeats, orders in, execution reports out, rejects. Each message has seq, timeUtc, inbound (true = user's engine sent it), msgType, raw FIX, and parsed tag/value fields. Pa Inputs: sessionId, afterSeq |
sandbox_get_orders | Working orders the user's engine has sent into the sandbox session: ClOrdID, symbol, side, qty, filled, leaves, price, status. Inputs: sessionId |
sandbox_get_session | Re-fetch a sandbox session's connection card by id, including whether auto-fill is on and when it expires. Inputs: sessionId |
sandbox_get_status | Is the user's FIX engine connected to the sandbox session? Returns state: connected, waiting (nobody logged on yet), disabled, or unknown. Inputs: sessionId |
sandbox_set_autofill | Turn automatic fills on or off for a sandbox session. On: every order the user sends is filled immediately at the security's last price. Off (default): orders are acknowledged and wait for sandbox_act_on_order. Inputs: sessionId, enabled |
Every block below points at https://mcp.fixsim.com/mcp. Pick your client and copy.
claude mcp add --transport http fixsim https://mcp.fixsim.com/mcp
{
"mcpServers": {
"fixsim": {
"command": "npx",
"args": ["-y", "mcp-remote", "https://mcp.fixsim.com/mcp"]
}
}
}{
"mcpServers": {
"fixsim": {
"url": "https://mcp.fixsim.com/mcp"
}
}
}{
"servers": {
"fixsim": {
"type": "http",
"url": "https://mcp.fixsim.com/mcp"
}
}
}{
"context_servers": {
"fixsim": {
"url": "https://mcp.fixsim.com/mcp"
}
}
}{
"mcpServers": {
"fixsim": {
"serverUrl": "https://mcp.fixsim.com/mcp"
}
}
}{
"mcpServers": {
"fixsim": {
"url": "https://mcp.fixsim.com/mcp"
}
}
}name: FIXSIM
version: 0.0.1
schema: v1
mcpServers:
- name: FIXSIM
type: streamable-http
url: https://mcp.fixsim.com/mcp{
"mcpServers": {
"fixsim": {
"httpUrl": "https://mcp.fixsim.com/mcp"
}
}
}{
"mcpServers": {
"fixsim": {
"type": "http",
"url": "https://mcp.fixsim.com/mcp"
}
}
}{
"mcpServers": {
"fixsim": {
"url": "https://mcp.fixsim.com/mcp"
}
}
}goose://extension?url=https%3A%2F%2Fmcp.fixsim.com%2Fmcp&type=streamable_http&id=fixsim&name=FIXSIM
It answered our last check on 19 October 2026 in 437 ms. Over 5 checks since 12 September 2026 it answered 5. Status here comes from Neuronto's own probes, not from the publisher.
21, as returned by the server's own tools/list on 24 September 2026: fixsim_act_on_orders, fixsim_cancel_order_out, fixsim_get_order_in, fixsim_get_session, fixsim_list_executions_in, fixsim_list_executions_out, fixsim_list_instances, fixsim_list_orders_in, and 13 more.
It answered our last check on 19 October 2026 in 437 ms. Over 5 checks since 12 September 2026 it answered 5.
Put the server under mcpServers in ~/.cursor/mcp.json with the URL https://mcp.fixsim.com/mcp. The exact JSON is above, with the same setup for Claude Code, Claude Desktop, VS Code, Windsurf, Zed, Gemini CLI and the rest.
It listed its tools to an anonymous client, so reading the tool list needs no key. Individual tools can still ask for credentials in their own inputs.
Publisher: io.github.gammathreetrading. Endpoint host: mcp.fixsim.com. ARD identifier: urn:air:io.github.gammathreetrading:mcp:fixsim.
First indexed 12 September 2026. The tools are exactly what the server returned; nothing on this page
is inferred from its name. Ranking in Neuronto search is never for sale.