FIXSIM
REMOTE · MCP.FIXSIM.COM · SCANNED SEP 20
Test FIX from Claude, ChatGPT, or Cursor: free sandbox FIX sessions or your own FIXSIM instances.
Available components
How this component scores in each security and reliability category. Every signal is checked automatically against the live server, and we only credit what we can confirm. How we score → Why this is hard to score →
Endpoint Security57
- The endpoint's TLS certificate is valid, in date, and uses a strong key. View diagnostics → Pass
- Authorisation check failed: no authorisation is required to call this server, and it exposes a tool marked destructive (sandbox_end_session). See how to fix → View diagnostics → Fail
- HTTPS is enforced; there's no plaintext access path. View diagnostics → Pass
- HSTS check failed: the Strict-Transport-Security header is absent. See how to fix → View diagnostics → Fail
- DNSSEC check failed: this domain isn't protected by DNSSEC. See how to fix → View diagnostics → Fail
Transport & Reachability100
- Verified streamable-http transport via a live MCP handshake. View diagnostics → Pass
Schema Quality & AI Usability79
- AI-judged instruction clarity (excellent).Pass
- Context-footprint check failed: tool/resource definitions use about 2332 tokens (~111/item across 21 items; 21 tools + 0 resources), over budget; trim descriptions and params. See how to fix → Fail
- Usage-examples check failed: none of the tools include examples. See how to fix → Fail
Stability & Change Management27
- Stability observed for 8 of 30 days with no destabilising changes; credit accrues until the full window elapses.Partial
Tool Coverage81
- 100% of tools have a non-trivial description (not blank, and not just the tool's name).Pass
- 42% of tool parameters carry a description.Partial
Tool Safety100
- No prompt-injection markers were found in the server instructions, tool names or descriptions we captured.Pass
- All 2 tool(s) whose name or description implies an irreversible operation declare an MCP destructiveHint annotation.Pass
- An AI judge read all 22 captured unit(s) of tool text and found none that tries to manipulate the model reading it.Pass
Capabilities100
- Implements a current MCP spec version (2026-07-28).Pass
How do I install the FIXSIM MCP server?
FIXSIM is a hosted endpoint at https://mcp.fixsim.com/mcp, so there is nothing to install locally. Ready-made configuration for Claude, Cursor, VS Code, Codex and 5 more is on this page, copied from each client's own documentation.
remote · mcp.fixsim.com
claude mcp add --transport http gammathreetrading-fixsim 'https://mcp.fixsim.com/mcp'
{
"mcpServers": {
"gammathreetrading-fixsim": {
"url": "https://mcp.fixsim.com/mcp"
}
}
} {
"servers": {
"gammathreetrading-fixsim": {
"type": "http",
"url": "https://mcp.fixsim.com/mcp"
}
}
} [mcp_servers.gammathreetrading-fixsim] url = "https://mcp.fixsim.com/mcp"
{
"$schema": "https://opencode.ai/config.json",
"mcp": {
"gammathreetrading-fixsim": {
"type": "remote",
"url": "https://mcp.fixsim.com/mcp",
"enabled": true
}
}
} openclaw mcp add gammathreetrading-fixsim --url 'https://mcp.fixsim.com/mcp' --transport streamable-http
mcp_servers:
gammathreetrading-fixsim:
url: "https://mcp.fixsim.com/mcp" {
"McpServers": {
"gammathreetrading-fixsim": {
"Transport": "http",
"Url": "https://mcp.fixsim.com/mcp"
}
}
} assistant mcp add gammathreetrading-fixsim -t streamable-http -u 'https://mcp.fixsim.com/mcp'
{
"mcpServers": {
"gammathreetrading-fixsim": {
"type": "http",
"url": "https://mcp.fixsim.com/mcp"
}
}
} The mcpServers block is a cross-client convention. Remote transports vary, so check your client's docs.
Every change we have recorded for this component, newest first. Security-relevant changes are always shown. ▲ marks a change for the better, ▼ a change for the worse; unmarked changes are neutral.
- 19 Sept 26 +1
No change was recorded against any check on this day. Stability & Change Management went from 20 to 23. That category is still filling its 30-day observation window: 6 days of observed history at the previous scan, 7 at this one. The score rises as the window fills, whether or not the server changes.
- 17 Sept 26 +1
No change was recorded against any check on this day. Stability & Change Management went from 13 to 17. That category is still filling its 30-day observation window: 4 days of observed history at the previous scan, 5 at this one. The score rises as the window fills, whether or not the server changes.
- 15 Sept 26 +1
No change was recorded against any check on this day. Stability & Change Management went from 7 to 10. That category is still filling its 30-day observation window: 2 days of observed history at the previous scan, 3 at this one. The score rises as the window fills, whether or not the server changes.
- 13 Sept 26 0
- Stability: unverified → 0.03 ▲ functional
- Server version: 0.1.1 → 0.1.2 functional
- Tool “fixsim_act_on_orders” changed its title: Act on inbound orders cosmetic
- Tool “fixsim_cancel_order_out” changed its title: Send an Order Cancel Request cosmetic
- Tool “fixsim_get_order_in” changed its title: Get inbound order cosmetic
- Tool “fixsim_get_session” changed its title: Get FIX session cosmetic
- Tool “fixsim_list_executions_in” changed its title: List inbound execution reports cosmetic
- Tool “fixsim_list_executions_out” changed its title: List outbound execution reports cosmetic
- Tool “fixsim_list_instances” changed its title: List FIXSIM instances cosmetic
- Tool “fixsim_list_orders_in” changed its title: List inbound orders cosmetic
- Tool “fixsim_list_orders_out” changed its title: List outbound orders cosmetic
- Tool “fixsim_list_securities” changed its title: List securities cosmetic
- Tool “fixsim_list_sessions” changed its title: List FIX sessions cosmetic
- Tool “fixsim_send_order” changed its title: Send a New Order Single cosmetic
- Tool “fixsim_send_raw_fix” changed its title: Send raw FIX messages cosmetic
- Tool “sandbox_act_on_order” changed its title: Fill, reject, or cancel a sandbox order cosmetic
- Tool “sandbox_create_session” changed its title: Create sandbox FIX session cosmetic
- Tool “sandbox_end_session” changed its title: End sandbox session cosmetic
- Tool “sandbox_get_messages” changed its title: Read sandbox FIX message log cosmetic
- Tool “sandbox_get_orders” changed its title: List sandbox orders cosmetic
- Tool “sandbox_get_session” changed its title: Get sandbox session cosmetic
- Tool “sandbox_get_status” changed its title: Check sandbox connection status cosmetic
- Tool “sandbox_set_autofill” changed its title: Set sandbox auto-fill cosmetic
- 12 Sept 26 64
First indexed and scored.
Diagnostic detail from the automated scan of this channel: what the scanner observed at each step, so you can see exactly where a check passed or failed. It is informational only and never changes the trust score.
Captured 20 Sept 2026 · Probed https://mcp.fixsim.com/mcp
TLS valid
Negotiated TLS 1.3 with TLS_AES_256_GCM_SHA384 .
| Subject | Issuer | Valid from | Valid until | Key | Signature | Serial |
|---|---|---|---|---|---|---|
| CN=mcp.fixsim.com | CN=GeoTrust TLS RSA CA G1,OU=www.digicert.com,O=DigiCert Inc,C=US | 6 Sept 2026 | 6 Mar 2027 | RSA 2048 | SHA256-RSA | d30009350b888bbd1bd32fbb2e47294 |
| SANs: mcp.fixsim.com | ||||||
| CN=GeoTrust TLS RSA CA G1,OU=www.digicert.com,O=DigiCert Inc,C=US (CA) | CN=DigiCert Global Root G2,OU=www.digicert.com,O=DigiCert Inc,C=US | 2 Nov 2017 | 2 Nov 2027 | RSA 2048 | SHA256-RSA | d07782a133fc6f9a57296e131ffd179 |
Background: What to check on a remote MCP endpoint →
DNSSEC insecure
Validation of mcp.fixsim.com. — Not signed
| Zone | DS | Keys | Algorithms | Outcome |
|---|---|---|---|---|
| . | trust_anchor | 20326, 38696 | 8, 8 | Verified |
| com. | present | 19718 | 13 | Verified |
| fixsim.com. | absent | Unsigned (proven) parent-signed NSEC/NSEC3 proves an unsigned delegation |
Authentication No authorisation required
The endpoint answered without asking for a token. Anyone who knows the URL can reach it.
| Result | No authorisation required |
|---|---|
| HTTP status | 200 |
Background: How OAuth 2.1 works in the 2026 MCP spec →
Transports 2 probes
| Transport | URL | Outcome | Status | Location |
|---|---|---|---|---|
| streamable-http | https://mcp.fixsim.com/mcp | Verified | 200 | |
| http (plaintext) | http://mcp.fixsim.com/mcp | HTTPS enforced | 301 | https://mcp.fixsim.com/mcp |
The tools this component advertises to a client, with an estimated token cost for each. Expand a tool to see its parameters and schema. The per-tool counts are indicative and are not scored directly; the schema's total context footprint is one signal in Schema Quality & AI Usability. A tool's description is untrusted text the model reads on every call, which is what makes this list a security surface and not just an inventory: how tool poisoning works →
fixsim_act_on_orders Act on inbound orders ~222
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.
| Name | Type | Req | Description |
|---|---|---|---|
| action | string | yes | One of: Ack, FullyExecute, PartialExecute, CancelRemaining, DoneForDay, AckCancelOrdReplaceReq, AcceptCancelOrdReplaceReq, RejectCancelOrdReplaceReq, Reject, Delete, Restate, Expire |
| apiKey | string|null | – | – |
| clOrdIds | array | yes | ClOrdIDs (tag 11) of the inbound orders to act on |
| instance | string | yes | – |
| lastPx | number|null | – | Fill price (LastPx) for executions |
| lastQty | number|null | – | Fill quantity (LastQty) for a partial execution |
| session | string | yes | – |
No output schema declared.
No examples provided.
fixsim_cancel_order_out Send an Order Cancel Request ~124
Have FIXSIM send an Order Cancel Request (35=F) for an order it previously sent out with fixsim_send_order.
| Name | Type | Req | Description |
|---|---|---|---|
| additionalTags | array|null | – | – |
| apiKey | string|null | – | – |
| clOrdId | string | yes | ClOrdID of the order to cancel (becomes OrigClOrdID, tag 41) |
| instance | string | yes | – |
| newClOrdId | string|null | – | New ClOrdID for the cancel request (tag 11); generated if omitted |
| session | string | yes | – |
No output schema declared.
No examples provided.
fixsim_get_order_in Get inbound order ~89
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.
| Name | Type | Req | Description |
|---|---|---|---|
| apiKey | string|null | – | – |
| clOrdId | string | yes | ClOrdID, FIX tag 11 |
| instance | string | yes | – |
| session | string | yes | – |
No output schema declared.
No examples provided.
fixsim_get_session Get FIX session ~59
Get one FIX session's settings and live state (logged in?, sequence numbers, connection details).
| Name | Type | Req | Description |
|---|---|---|---|
| apiKey | string|null | – | – |
| instance | string | yes | – |
| session | string | yes | Session name from fixsim_list_sessions |
No output schema declared.
No examples provided.
fixsim_list_executions_in List inbound execution reports ~116
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).
| Name | Type | Req | Description |
|---|---|---|---|
| apiKey | string|null | – | – |
| execId | string|null | – | Optional ExecID (tag 17) filter |
| instance | string | yes | – |
| limit | integer | – | Max rows to return, newest first (default 25, max 200) |
| session | string | yes | – |
No output schema declared.
No examples provided.
fixsim_list_executions_out List outbound execution reports ~143
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.
| Name | Type | Req | Description |
|---|---|---|---|
| apiKey | string|null | – | – |
| clOrdId | string|null | – | Optional ClOrdID (tag 11) to narrow to one order |
| instance | string | yes | – |
| limit | integer | – | Max rows to return, newest first (default 25, max 200) |
| session | string | yes | – |
No output schema declared.
No examples provided.
fixsim_list_instances List FIXSIM instances ~72
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.
| Name | Type | Req | Description |
|---|---|---|---|
| apiKey | string|null | – | FIXSIM API key. Omit when the connector sends it as a header. |
No output schema declared.
No examples provided.
fixsim_list_orders_in List inbound orders ~151
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.
| Name | Type | Req | Description |
|---|---|---|---|
| apiKey | string|null | – | – |
| instance | string | yes | – |
| limit | integer | – | Max rows to return, newest first (default 25, max 200) |
| orderStatus | string|null | – | Optional FIX OrdStatus (tag 39) filter |
| session | string | yes | – |
No output schema declared.
No examples provided.
fixsim_list_orders_out List outbound orders ~90
Orders FIXSIM sent OUT on a session (created with fixsim_send_order). Pass clOrdId to fetch one.
| Name | Type | Req | Description |
|---|---|---|---|
| apiKey | string|null | – | – |
| clOrdId | string|null | – | – |
| instance | string | yes | – |
| limit | integer | – | Max rows to return, newest first (default 25, max 200) |
| session | string | yes | – |
No output schema declared.
No examples provided.
fixsim_list_securities List securities ~53
Securities (symbol, last price, CUSIP, ISIN) configured on an instance. FIXSIM prices fills from these.
| Name | Type | Req | Description |
|---|---|---|---|
| apiKey | string|null | – | – |
| instance | string | yes | – |
No output schema declared.
No examples provided.
fixsim_list_sessions List FIX sessions ~69
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.
| Name | Type | Req | Description |
|---|---|---|---|
| apiKey | string|null | – | – |
| instance | string | yes | Instance name from fixsim_list_instances |
No output schema declared.
No examples provided.
fixsim_send_order Send a New Order Single ~233
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.
| Name | Type | Req | Description |
|---|---|---|---|
| additionalTags | array|null | – | Extra FIX tags, e.g. [{tag:59,value:"0"}] |
| apiKey | string|null | – | – |
| clOrdId | string | yes | ClOrdID (tag 11) to assign; must be unique on the session |
| instance | string | yes | – |
| ordType | string | yes | OrdType (tag 40): 1=Market, 2=Limit |
| orderQty | number | yes | OrderQty (tag 38) |
| price | number|null | – | Price (tag 44), required for limit orders |
| session | string | yes | – |
| side | string | yes | Side (tag 54): 1=Buy, 2=Sell, 5=Sell short |
| symbol | string | yes | Symbol (tag 55) |
No output schema declared.
No examples provided.
fixsim_send_raw_fix Send raw FIX messages ~144
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.
| Name | Type | Req | Description |
|---|---|---|---|
| apiKey | string|null | – | – |
| fixMessages | array | yes | Raw FIX messages, e.g. 35=D|11=ORD1|55=IBM|54=1|38=100|40=2|44=150.25|59=0 |
| instance | string | yes | – |
| session | string | yes | – |
No output schema declared.
No examples provided.
sandbox_act_on_order Fill, reject, or cancel a sandbox order ~96
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.
| Name | Type | Req | Description |
|---|---|---|---|
| action | string | yes | fill, partial, reject or cancel |
| clOrdId | string | yes | ClOrdID (tag 11) of the order |
| sessionId | string | yes | – |
No output schema declared.
No examples provided.
sandbox_create_session Create sandbox FIX session ~160
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.
| Name | Type | Req | Description |
|---|---|---|---|
| fixVersion | string | – | FIX.4.0, FIX.4.2, FIX.4.4 (default) or FIX.5.0SP2 (rides FIXT.1.1) |
No output schema declared.
No examples provided.
sandbox_end_session End sandbox session ~39
End a sandbox session now instead of waiting for it to expire. Frees the slot for the user's IP.
| Name | Type | Req | Description |
|---|---|---|---|
| sessionId | string | yes | – |
No output schema declared.
No examples provided.
sandbox_get_messages Read sandbox FIX message log ~115
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.
| Name | Type | Req | Description |
|---|---|---|---|
| afterSeq | integer | – | Return only messages with seq greater than this |
| sessionId | string | yes | – |
No output schema declared.
No examples provided.
sandbox_get_orders List sandbox orders ~47
Working orders the user's engine has sent into the sandbox session: ClOrdID, symbol, side, qty, filled, leaves, price, status.
| Name | Type | Req | Description |
|---|---|---|---|
| sessionId | string | yes | – |
No output schema declared.
No examples provided.
sandbox_get_session Get sandbox session ~45
Re-fetch a sandbox session's connection card by id, including whether auto-fill is on and when it expires.
| Name | Type | Req | Description |
|---|---|---|---|
| sessionId | string | yes | Session id from sandbox_create_session |
No output schema declared.
No examples provided.
sandbox_get_status Check sandbox connection status ~46
Is the user's FIX engine connected to the sandbox session? Returns state: connected, waiting (nobody logged on yet), disabled, or unknown.
| Name | Type | Req | Description |
|---|---|---|---|
| sessionId | string | yes | – |
No output schema declared.
No examples provided.
sandbox_set_autofill Set sandbox auto-fill ~69
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.
| Name | Type | Req | Description |
|---|---|---|---|
| enabled | boolean | yes | – |
| sessionId | string | yes | – |
No output schema declared.
No examples provided.
What is the FIXSIM MCP server?
FIXSIM is an MCP server listed in the public MCP registry as io.github.GammaThreeTrading/fixsim. Test FIX from Claude, ChatGPT, or Cursor: free sandbox FIX sessions or your own FIXSIM instances. This page covers its hosted endpoint (https://mcp.fixsim.com/mcp).
Is the FIXSIM MCP server safe to use?
FIXSIM scores 67 out of 100 on VerifyMCP. That is a record of what we were able to check automatically, not an endorsement. The category breakdown on this page shows every signal behind the number, including the ones we could not confirm.
What tools does the FIXSIM MCP server expose?
FIXSIM exposes 21 tools: fixsim_list_orders_out, sandbox_get_status, fixsim_send_order, fixsim_list_orders_in, fixsim_list_executions_in, and 16 more. Their descriptions and schemas cost roughly 2,182 tokens of context every time the server is loaded.
Does the FIXSIM MCP server require authentication?
No. We connected to FIXSIM without credentials and it answered, so anything it exposes is reachable by anyone who knows the address.
Is the FIXSIM MCP server still maintained?
FIXSIM is still listed as active in the MCP registry. We last reached this channel on 20 September 2026. Those dates come from our own scans of the registry and the channel itself, not from anything the publisher announced.