What's New in FIXSIM

Everything on this page has shipped and is live for the plans that include it. Newest first. We do not publish a roadmap here; if you want to know whether something is coming, ask us.

Last updated September 14, 2026

September 2026

Enterprise single sign-on. Sign in to FIXSIM with Microsoft Entra ID, Okta, or any OpenID Connect provider. Users from your approved email domains are provisioned automatically on first sign-in, and your firm can require SSO for every login. Included in the Enterprise plan. Setup guide: Single Sign-On.
Bust or correct the last execution. A new order action, available from the blotter and as a rule action, busts or corrects the most recent fill on an order. FIXSIM sends the matching execution report (a trade cancel or trade correct that references the original fill) and reverts the order's cumulative quantity and average price, so your system can prove it handles a bust the way the venue would send it.
Test FIX from Claude, ChatGPT, or Cursor. FIXSIM publishes an MCP server at mcp.fixsim.com. Ask your AI assistant for a sandbox FIX session, connect your engine, and have it read the wire, fill or reject your orders, and explain the execution reports. Customers add an API key and the same assistant drives their own instances. How-to: Test FIX from Claude.

August 2026

Developer Sandbox. A free hosted FIX endpoint at sandbox.fixsim.com. One click gives you a host, port, and CompIDs, with a live parsed message viewer and a blotter for acting as the counterparty. No account required. Details: Developer Sandbox.
Multiple instances in separate browser tabs. Users with more than one instance can open each in its own tab from a single login. Every tab keeps its own instance.
Execution summary strip. Order execution pages open with a one-line summary: average price, cumulative quantity, and a fill bar.
Repeating groups on manual executions. Execute Qty/Price accepts repeating tags, and NoMiscFees (136) can be sent on execution reports and New Order Singles.
Breadcrumbs on every drill-down. Blotter, order, execution, and message detail pages show the trail you followed and link back up.
Sidebar version badges. Each session shows its FIX version as a badge, and long session names wrap instead of being cut off.
Trial restart and a ready-made QuickFIX config. An expired trial restarts with one click, and the connection card offers a downloadable QuickFIX .cfg with the session details already filled in.

July 2026

FIXatdl Algo Tickets. Upload a FIXatdl file, preview the rendered ticket, and launch algo orders from the outbound blotter. Enterprise plan. Guide: Algo Tickets.
Custom execution mode honors count or quantity. Partial executes in Custom mode follow whether you configured a number of fills or a fill quantity.

June 2026

User roles and instance permissions. ClientAdmin, PowerUser, and User roles, per-user instance access, and a self-service password page. Guide: Managing Users.
Firm-level API keys. A client-wide key that is not tied to any one user, for CI pipelines and shared automation. Guide: REST API.
Bulk edit on Manage Users. Set the role or instance access for many users at once.

May 2026

DK Trade capture. Inbound Don't Know Trade messages (35=Q) are stored against the execution and exposed through the REST API. Guide: DK Trades.
Sleeping session state. A session outside its SessionTime window shows a moon icon in the sidebar instead of looking like a failure.
API timestamps in explicit UTC. Every date and time the REST API returns carries a Z suffix.

April 2026

Rules act on cancel and replace. Rules can trigger on Order Cancel Request (35=F) and Order Cancel/Replace Request (35=G), and each rule can define its own Custom Exec behavior. Guide: Rule Builder.
Rules pages redesigned. A session filter at the top, Create New carries the session with it, and saving a rule lands you on its actions page.
Per-user custom tag overrides. Each user can override outbound tag values without changing the session defaults.
Bulk cancel open orders by time in force. End-of-day sweeps cancel every open order with a given TimeInForce in one action.

January to March 2026

Server-side paging on every blotter and report. Large histories load page by page instead of all at once.
Log Replay handles very large files and pipe-delimited logs. Guide: Log Replay.
Date and time range pickers on reporting pages.
High-volume session mode. Asynchronous persistence, immediate queueing of auto-executes, and multiple partial executes per order, for load and soak tests.
Source IP on connected sessions. The session view shows the address your engine connected from.
TransactTime stamped at send time on raw messages. Large batches of raw messages carry the actual send time in tag 60.
Paste anything into Raw Messages. The parser strips surrounding log text, timestamps, and delimiters and keeps only the FIX messages.

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