MCP.Market

FIXSIM MCP server

online · 100% uptime
by GammaThreeTrading·io.github.GammaThreeTrading/fixsim·v0.1.2·1 stars
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Test FIX from Claude, ChatGPT, or Cursor: free sandbox FIX sessions or your own FIXSIM instances.

A89/100grade A
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Safety scan
A89/100

full report

Adoption
Growing

1 stars

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FIXSIM tools (21, 8 write)

write = sends, deletes, buys or posts
  • fixsim_act_on_ordersFree

    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 on the FIX session. Give one or more ClOrdIDs; for executions supply lastPx and, for a partial, lastQty.

  • fixsim_cancel_order_outwrite actionFree

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

  • fixsim_get_order_inwrite actionFree

    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.

  • fixsim_get_sessionFree

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

  • fixsim_list_executions_inFree

    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).

  • fixsim_list_executions_outFree

    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.

  • fixsim_list_instancesFree

    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.

  • fixsim_list_orders_inwrite actionFree

    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): 0 new, 1 partially filled, 2 filled, 4 canceled, 8 rejected.

  • fixsim_list_orders_outwrite actionFree

    Orders FIXSIM sent OUT on a session (created with fixsim_send_order). Pass clOrdId to fetch one.

  • fixsim_list_securitiesFree

    Securities (symbol, last price, CUSIP, ISIN) configured on an instance. FIXSIM prices fills from these.

  • fixsim_list_sessionsFree

    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.

  • fixsim_send_orderwrite actionFree

    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.

  • fixsim_send_raw_fixwrite actionFree

    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 types the other tools do not cover.

  • sandbox_act_on_orderwrite actionFree

    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.

  • sandbox_create_sessionwrite actionFree

    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 the expiry (sessions last 4 hours, cap 100 application messages per day). The user's FIX engine connects as the initiator; FIXSIM is the acceptor and acknowledges every order. Keep the returned id; every other sandbox tool needs it.

  • sandbox_end_sessionFree

    End a sandbox session now instead of waiting for it to expire. Frees the slot for the user's IP.

  • sandbox_get_messagesFree

    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. Pass afterSeq (the last seq you saw) to fetch only new messages. Use this to explain what happened on the wire.

  • sandbox_get_ordersFree

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

  • sandbox_get_sessionFree

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

  • sandbox_get_statusFree

    Is the user's FIX engine connected to the sandbox session? Returns state: connected, waiting (nobody logged on yet), disabled, or unknown.

  • sandbox_set_autofillFree

    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.

Public scan report

scanner v0.1.10 · 2026-10-03 · same rubric, same numbers if you re-run it

no findings
  • –Code scanremote-only server, no package to scann/a
  • Live reliabilityremote reachable in 910ms20/20
  • Tool poisoning21 tool descriptions checked15/15
  • Auth qualityAPI key sent as a header8/15
  • Maintenancelast push 21 days ago15/15
  • Maintainer identityregistry namespace matches repository owner; GitHub account older than a year9/10
Overall 89/100. Components that don't apply are left out of the denominator. Any critical finding is an F.RubricAppeal a findingJSON

How FIXSIM compares

Against every graded MCP server, from our own scans and uptime checks. Updated after each scan run.

Safety score
89/100
higher than 80% of 48,243 servers
Tools
21
the typical server has 7
Tools that change things
38%
typical: 0%. Fewer write tools means less an agent can break
Uptime
100%
of our recent checks; the typical remote server answers 100%
Response time
431 ms
faster than 38% of 30,027 servers
GitHub stars
1
more than 65% of 28,706 servers

What its tools let an agent do: 13 read · 8 change

Install FIXSIM in Claude Code, Cursor or VS Code

claude mcp add --transport http fixsim https://mcp.fixsim.com/mcp
Add to Cursor

What the publisher says

From the FIXSIM repository's README, as published. We do not edit it. Read it on GitHub

fixsim-mcp

An MCP server for FIXSIM, the hosted FIX protocol simulator. Add it to Claude, Cursor, VS Code, or ChatGPT and test FIX from a conversation:

"Create a FIX 4.4 test session for me, then tell me when my engine has logged on and show me the first order it sent."

Two tool families live on one endpoint:

Connect

Hosted endpoint: https://mcp.fixsim.com/mcp (read-only variant: https://mcp.fixsim.com/mcp/readonly).

Claude Code

claude mcp add --transport http fixsim https://mcp.fixsim.com/mcp --header "x-api-key: YOUR_FIXSIM_API_KEY"

Leave off --header if you only want the free sandbox tools.

Cursor / VS Code (mcp.json)

{
  "mcpServers": {
    "fixsim": {
      "url": "https://mcp.fixsim.com/mcp",
      "headers": { "x-api-key": "YOUR_FIXSIM_API_KEY" }
    }
  }
}

Claude.ai / Claude Desktop: Customize → Connectors → Add custom connector → URL https://mcp.fixsim.com/mcp. Choose authentication None for the sandbox. To use your own instances, add a request header x-api-key (header support in the connector dialog is rolling out; if you do not see it, use Claude Code or Cursor for now).

Tools

Sandbox (no auth)

Sandbox limits: 100 application messages per session per day, 4-hour sessions, a handful of sessions per caller.

FIXSIM instances (API key)

The /mcp/readonly endpoint exposes the same tools but refuses the ones that send.

Every fixsim_* call is checked against the instances your key is entitled to, and is rate-limited per key (120 calls per minute by default).

Run it yourself

Requires .NET 8.

dotnet run --project src/FixSim.Mcp --urls http://localhost:5199

Configuration (appsettings.json or environment variables such as FixSim__BaseUrl):

Shortened. The full README is on GitHub.

Nothing above is checked by us. What we check is on the safety report.

FIXSIM: common questions

Is FIXSIM MCP server safe?
Yes, by our scan: it is graded A (89/100). Read the FIXSIM safety report
How do I install FIXSIM?
It runs remotely at mcp.fixsim.com. Add it to Claude Code, Cursor, VS Code or Claude Desktop with the snippets above, or call it through the mcp.market gateway without installing anything.
Does FIXSIM need an API key?
Yes. The registry entry asks for x-api-key.
Is FIXSIM maintained?
The last commit was 54 days ago (2026-09-13). The latest release is v0.1.2.
Is FIXSIM up?
100% of our last 28 checks got an answer. We check remote servers about four times a day.
How does FIXSIM compare with other MCP servers?
safety score 89/100 (higher than 80% of 48,243 servers); tools 21 (the typical server has 7); tools that change things 38% (typical: 0%. Fewer write tools means less an agent can break). Full comparison.