Rithmic vs ProjectX for Prop Traders: How the Two Connections Differ

Rithmic vs ProjectX is a question that comes up once you hold accounts at more than one prop firm, because the two connection types behave differently even though they end in the same place: orders reaching your futures account. This guide compares them neutrally, as they work when you connect accounts to WeCore. It does not rank them. Which one applies to you is decided by your firm, not by preference.

Checked 11 October 2026. Statements about Rithmic and ProjectX come from the official pages linked below, which we read on that date. Statements about WeCore come from how the product works today. Firms change platforms, so confirm with your firm which one your account uses.

The short version

The rest of the article explains each row.

What Rithmic is

Rithmic's website describes three programmatic interfaces: R | API+ (C++ and .NET), R | Protocol API (a wire-level specification using WebSockets and Google Protocol Buffers, usable from any language) and R | Diamond API (ultra-low latency, Linux only). Rithmic also publishes an exchange simulator described as connecting to live exchange data while filling orders in a simulated matching engine, and says the same environment is used for conformance testing of API integrations. See Rithmic's API page and exchange simulator page.

For a prop trader this means the Rithmic connection is made against the infrastructure that sits behind your firm. You do not buy Rithmic access directly in that case. The firm provisions your Rithmic login, and the login belongs to a specific Rithmic system that the firm uses.

What ProjectX / TopstepX is

ProjectX provides the TopstepX platform and a documented Gateway API. Its documentation describes logging in with a username and an API key, receiving a session token valid for 24 hours, and reusing that token for REST requests and realtime connections. The rate limits page listed 50 requests per 30 seconds for historical bars and 200 requests per 60 seconds for other endpoints when we read it, with HTTP 429 returned when exceeded.

On the firm side, Topstep's API Access page states that the API is a separate subscription and that live funded accounts are not allowed to trade through it. Details are in the Topstep automation rules article.

Which firms use which

In WeCore today:

• Rithmic: Apex Trader Funding, Lucid Trading, Tradeify, Take Profit Trader, Elite Trader Funding, TradeDay, Bulenox, Earn2Trade and OneUp Trader are offered as funding-firm options. The picker shows which phase of a firm is covered, for example evaluation or funded. A firm that is not in the picker is not supported yet.
• ProjectX / TopstepX: Topstep.
• Also available: tastytrade (direct broker connection, open to all customers) and the WeCore Paper simulation account. Tradovate and NinjaTrader are not available yet.

A firm may add or change platforms over time. The reliable way to know is the firm's own platform page and your account welcome email. For firm automation rules, see prop firms that allow automation and the Lucid bots article.

Credentials and setup, side by side

Rithmic

You pick the funding firm and the account type, and WeCore selects the right Rithmic system. If your firm is missing, there is an option to type the system name exactly as the firm gave it. You then enter the Rithmic username and password. If the connection returns "permission denied", it is a permission rather than a typo: sign in once to R | Trader and accept any agreements, check you chose the right firm, and ask the firm to confirm the account is enabled for API trading.

ProjectX / TopstepX

You subscribe to ProjectX API Access, link it in TopstepX under Settings, API, add an API key and copy it in full. In WeCore you enter the TopstepX username and the key, then choose one account from the list. One TopstepX login usually holds several accounts, and each connected account counts separately. One extra setting matters: TopstepX needs Auto OCO Brackets switched on, otherwise it refuses entries that carry a stop and target.

One login at a time

The two connection types differ clearly here:

• Rithmic limits you by login. Only one platform should be connected to the same Rithmic login at a time. In WeCore, all accounts under one Rithmic login must sit in the same place, either on the website or on your own trading server.
• ProjectX / TopstepX limits by account in WeCore. One account can be on your server and another account of the same login on the website, but the same account cannot be in both, and the same account cannot be connected twice.

For the practical side of hosting, see running strategies on your own server.

Simulation and data

Rithmic's exchange simulator pairs live data with simulated fills. WeCore adds its own layer: every new broker account starts in Simulation mode, and live orders require saved risk rules and an explicit switch. WeCore also has a WeCore Paper account, a built-in simulation account without a broker login, whose prices come from one of your connected Rithmic or Topstep accounts. Paper limit entries fill only when price actually trades through the level.

Data is where you may notice differences. Screens that show Rithmic data carry the "Market Data by Rithmic" logo, a licensing requirement. Where the market data on your account comes from, and what the firm charges for it, is determined by your firm. For fill quality in any simulation, read slippage and execution costs and backtesting versus live trading.

What neither connection changes

Neither connection decides whether a firm permits automation. Each firm's rules about bots, high-frequency trading, servers and copiers come from the firm's own pages. A working connection is not an approval. Both connection types also leave order-level risk to you: daily loss limits, position size and trading hours are set in your WeCore risk rules, and exit orders always pass them.

If you want to see how this looks in practice, you can view the plans or create an account and start in simulation. Ready-made strategies for your own server are on the WeAlgo page.

FAQ

Is Rithmic or ProjectX required for my prop firm?

It depends on the firm and sometimes on the account type. In WeCore, Topstep uses ProjectX / TopstepX and the firms listed above use Rithmic. Confirm your platform with your firm.

Do I need an API key for Rithmic?

In WeCore the Rithmic connection uses your Rithmic username and password with the right funding firm, not an API key. The firm must have enabled the account for API trading.

Can I use the same login on two platforms at once?

For Rithmic, only one platform should be connected to a login at a time. For TopstepX in WeCore the rule applies per account. Check your firm's own rules as well.

Which one has a simulation environment?

Rithmic publishes an exchange simulator, and WeCore starts every new account in Simulation. Topstep's API page says its API gateway operates in simulated environments; check the firm's page for what each account stage allows.

Does WeCore rank Rithmic against ProjectX?

No. The two are connection types determined by your firm. This article only describes how they differ.

Facts about Rithmic and ProjectX were read on their official pages on 11 October 2026 and may have changed. WeCore is not affiliated with these companies or with any prop firm. This article is general information, not investment advice, and does not promise any result. Futures trading carries a high risk of loss.