Synthesis

What it is

A browser trading desk that puts the position, the chart and the record of what other addresses are doing on one screen, across two venues instead of one. The navigation is five items — Trade, Multiview, Discover, Copytrade, Portfolio — and the site's front door is not a marketing page but a market, already priced, with the trade panel open.

On a market page you get a candlestick chart with 1H through ALL ranges, the price, 24-hour volume, liquidity and close date, every outcome in a multi-outcome event with its Yes and No quote side by side, and tabs for orders, positions, copytrades, activity, news, related markets, top holders, the resolution rules and a chat. The order ticket takes market and limit orders in shares. Charting is TradingView's library, which the terms say in as many words.

Discover is the screener half: filter by venue — Polymarket or Kalshi — by category, by tag, sort by volume, liquidity, newest or ending soon, and there are standing tabs for arbitrage and for bonds. Multiview is a several-markets-at-once desk and refuses to load below desktop width, which tells you which machine the product was designed for.

Copytrade is its own section rather than a feature buried in a settings page. You add a target, pick a mode, set allocated funds and a buy amount, and the subscription runs until you stop it. Sign-in is email, Google, an EVM wallet, Solana or Telegram.

Availability

Trading from the United States is barred by the terms, in capitals. The Terms of Use name the United States, the United Kingdom, France, Ontario, Singapore, Poland, Thailand, Australia, Belgium and Taiwan, plus the comprehensively sanctioned territories, and follow the list with the sentence that there are no exceptions. Using a VPN to get around it is prohibited, and the stated consequence is that a wallet may be placed in close-only mode.

Reading is a different permission from trading, and the terms say so explicitly. The site is split into what it calls content features — the market data, the news, the prices — and technology features, which are the wallet-signed messages that place a trade. A person in a restricted jurisdiction is permitted the first and not the second. In practice that is why a US reader can open any market on the site and see it priced.

The document contradicts itself about two countries. The capitalised notice at the top lists Australia and Belgium among the restricted places; the defined term "Restricted Jurisdictions" further down the same page does not name either. If you are in one of those two, you are reading a document that says both things.

There is no identity check. Sign-in is an email address, a Google account, a wallet signature or Telegram, and nothing on the way in asks for a document. That is a fact about Synthesis and not about the venue behind it — Polymarket runs its own restriction list, which is stricter than this one in Europe, and it is the one that decides whether a fill happens.

That is why the jurisdictions above are narrower than the terms. The field is built from Polymarket's international book, with Synthesis's own bars taken out — which drops most of western Europe and the four Canadian provinces Polymarket blocks. Kalshi markets are in the listing too, and since this card was first written the vendor's documentation has said they are traded on Solana. The restrictions on that Solana route were not read for this card, so it adds nothing to the field yet.

Read from the vendor's own Terms of Use and Privacy Policy on 20 September 2026. Neither document carries a last-updated date, which is the second thing to know about them.

Pricing

Copy trades cost 0.50% of the order (0.25¢ a share at 50¢), on top of the venue's fee. The Copytrade page of the vendor's documentation ends on one line: "A 0.50% fee (50 bps) is charged on all copytrade orders." That covers copy and counter mode, buys and sells. The page does not name the base in so many words, but every amount on it is in USDC — a 10% copy of a 100 USDC buy is a 10 USDC buy, and a fixed buy has a 1 USD minimum — so the 0.50% is read here as a share of what the order costs. At 50 cents that is 0.25 cents a share, or 0.25% of the one-dollar payout, which is the 0.25 in both fee fields. Read as a share of the payout instead, it would take half a cent from a contract costing one cent, and nothing on the page points that way. Whether a copied position is charged again when it is redeemed is not stated.

An order you place yourself has no published price, either way. There is still no pricing page on the main site (the path 404s). The documentation's FAQ, deposit and withdrawal pages carry no trading fee, and the Terms of Use, which run to several thousand words and cover indemnity, arbitration and a liability cap of 100 US dollars, never mention a charge to the user. The fee fields describe the copy path because it is the only one with a published rate. They do not claim that a market or limit order you enter by hand costs 0.25%, and they do not claim that it is free. A front end that routes orders to somebody else's book can take a margin inside the fill, where nobody outside can see it.

What you will pay for certain is the venue's own cost: on Polymarket that is the taker fee applied to the price, and on Kalshi it is the exchange's own formula.

Moving money. Deposits and withdrawals take USDC, USDC.e and USDT on eight chains. The withdrawal page warns that a USDC withdrawal on Solana "may incur a withdrawal fee to cover rent if the receiving account isn't initialized", and gives no amount. The rewards programme pays points for trading volume and referrals and does not say what a point is worth.

Read from the documentation's Copytrade, FAQ, Deposit, Withdrawal and Rewards pages and from the Terms of Use on 9 October 2026. None of them carries a date.

Markets & resolution

Synthesis resolves nothing and lists nothing. Every question, every price and every outcome belongs to the venue underneath — Polymarket's on-chain markets, settled in USDC on Polygon and resolved through the UMA optimistic oracle, and Kalshi's exchange-listed contracts, resolved under a rulebook filed with the CFTC. Those two resolution regimes are not alike, and a screen that renders them in the same row does not make them alike: one can be disputed by a token holder posting a bond, the other cannot.

The venue label is printed on each market page, which is the one thing a cross-venue desk has to get right. The categories the discovery page browses by — crypto, sports, US politics, geopolitics, mentions, economics, finance, companies, tech, culture, science — are its own grouping over whatever the two venues list, not a taxonomy either venue publishes.

Integrations

The charting is TradingView's library, named in the terms. Sign-in accepts email, Google, an EVM wallet, Solana and Telegram. The portfolio page carries an API tab beside Overview, Rewards and Settings, but it sits behind the login wall. The documentation site the vendor now runs has no API section, and the one OpenAPI file it links was, on 9 October 2026, the documentation host's sample plant-store specification rather than anything about Synthesis. So nothing here claims an API exists in a form you could build against, and the flag above says no.

There is no repository, no published SDK, no MCP server and no export button.

Limitations

Nothing about the product is dated. No changelog, no version number in the interface, no last-updated line on either legal document or on any page of the documentation. For a product that holds an order ticket over somebody else's order book, that is the single most useful missing fact, because a terminal breaks when the venue changes its API and you would learn about it from your own failed order.

Copytrading is an instruction to submit orders on your behalf, and the documentation puts it in those words: "When your target buys or sells, Synthesis executes the same trade on your behalf using your configured settings." The settings are now documented. You can copy the target or take the other side, size as a percentage of their trade, as a fixed amount with a 1 USD minimum or as a share of your balance, and cap the total. Filters cover slippage (0.1 to 100 cents), price, the target's trade size, time to resolution, category and exposure per market and per event. A trade that fails a filter is skipped, not resized. Two things are still undocumented: how fast a target's fill is detected, and how the order is signed. The documentation says only that the account's wallet is created and secured by Privy and that its key can be exported. It does not say what lets Synthesis sign while you are away. The terms disclaim any responsibility for execution price, slippage, partial fills or failure to execute at all.

A liability cap of 100 US dollars. The terms set the company's aggregate liability at that figure, choose Panamanian law, and require individual arbitration in Panama with a class-action waiver. That is the recourse, stated plainly, and it is worth reading before the deposit rather than after.

Nothing is open source and nothing is self-hosted. If the front end goes away, so does every view you built in it. Positions are on-chain and would survive; the desk would not.

Alternatives

PMXT and CCXT are the code version of the same idea — one interface over several venues — and they run on your keys instead of somebody else's front end, which is the trade for having to write the interface yourself. Predictefy sells a hosted multi-venue layer with documented endpoints and a published price.

Stand and Bullpen are the nearest front ends with copy trading built in, over Polymarket and Hyperliquid rather than Kalshi.

If what you actually want is the analytics and not the order ticket, Polyrama and Polymarket Analytics do the reading half without asking you to route a trade through them, and CrossOdds does not trade at all: it matches the same question across Kalshi and Polymarket and prints the gap, for 20 USD a month with an API. And if you are in the United States, no front end fixes that: the venue you can use is Polymarket US or Kalshi directly.