API and Liquidity Provider Agreement

This API and Liquidity Provider Agreement (the “Agreement”) is between you and Theta Labs Markets, Inc. (“updown”, “we”, “us”). It is part of our Terms of Service, which still apply in full. If the two conflict on the Trade API or the maker rebate program, this Agreement governs.

By using or accessing the updown Trade API, or by placing an order that rests on an updown order book, you agree to be bound by this Agreement. If you use the API for a company or other entity, you confirm that you have authority to bind it, and “you” means that entity. This is version 2026-10-28.

The Trade API lets a program (a bot, a market maker, an AI agent) read markets and trade as your account using an API key you create on your API keys page.

• Your keys, your orders. Every order placed with your key is your order, and you are responsible for it as if you had placed it yourself. Keep your keys secret, and revoke a key at once if you think it was exposed. A key can never withdraw, transfer or change your account.
• Limits. Use the API within its documented rate limits and your keys' own limits, and don't try to get around them, for example by spreading requests over many keys or accounts.
• Your systems. You are responsible for your own software and risk controls, including position and loss limits and cancelling your orders when your connection or data fails. We don't guarantee the API will always be available, fast or error-free.
• Data. You may use market data from the API for your own trading and research. Don't resell or redistribute it, or use it to build a competing service, without our written permission.
• Changes. We may change the API. We will try to give 30 days' notice of a change that breaks existing integrations, except when we need to act sooner to protect the exchange, our users or to comply with law. We may suspend or revoke keys that breach this Agreement or put the Service at risk.

A maker order is a limit order that rests on the book. A taker order is one that fills against an order already resting. When another customer's taker order fills against your resting order on an updown order book, you automatically earn a rebate: a share of the fee that customer paid. There is nothing to sign up for. It applies to your orders however you place them, through the Trade API or on the website, and you keep paying no fee on your own maker fills.

The taker fee is 0.07 × contracts × p × (1 − p), where p is the fill price in dollars. It is largest at 50¢ (1.75¢ per contract) and falls toward zero near 0¢ and $1. For example, when a taker buys 100 contracts from your resting order at 50¢ on a crypto market, the taker pays $1.75 and you earn 30% of it, about $0.53.

• Each fill earns the share in force when it filled. Rebates are computed in US dollars and rounded down to the millionth of a dollar.
• Only fees we actually collect from a customer fund a rebate. A fill earns nothing when the other side is updown itself (our market maker or treasury), one of our simulated trading accounts, you, or an account linked to yours (for example, a team member of your account, or an account you are a member of).
• Markets in other categories earn no rebate for now.

Rebates add up over each UTC day and become claimable once that day is over. You claim them from your API keys page. A claim pays your whole claimable balance, at least $1.00, in USDG to your updown wallet, and needs the current Terms of Service accepted. Anything under the minimum stays in your balance until it reaches it.

We may hold a payment while we review the fills behind it, and we will tell you if we do. If we pay a rebate by mistake or pay more than this Agreement provides, we may deduct the excess from your later rebates.

You must provide genuine liquidity. In particular you must not:

• trade with yourself, with accounts you control or share an owner, team or beneficial owner with, or with anyone you have arranged the trade with in advance;
• wash trade, or trade to create volume, fees or rebates rather than to take a position;
• spoof or layer the book: place orders you intend to cancel before they can fill, to mislead others about supply or demand;
• split your activity across several accounts, or use someone else's account, to earn more than one account would.

If we reasonably decide that you have breached this Agreement, we may stop your account earning rebates, void the rebates you earned while the breach was going on (or all of them, if we can't separate the affected fills), deduct any already paid from later rebates, suspend or revoke your API keys, and use any other remedy in our Terms of Service. Our self-trade prevention stops your order from filling against your own resting order. Don't rely on it as your only control.

• Any customer in good standing who may trade on updown under our Terms of Service.
• Not our employees, contractors or affiliates, or anyone trading on their behalf.
• Not an account we have suspended, restricted, banned or excluded from the program, or one we run ourselves.

While you are earning rebates (any time in the last 30 days), your account shows a “Liquidity Provider” label. Only you can see it: we don't show other users who earns rebates or how much.

Using the API or earning rebates doesn't make you our agent, partner or employee, and you must not say that it does. Your orders get no priority, no special information and no special treatment on the book: they match by price and then time like everyone else's.

You trade with your own money and at your own risk. A resting order can fill at any time it is on the book, including in fast markets and in a window's final seconds. We don't promise any level of rebates, fills or trading volume. A rebate is never a guarantee against trading losses.

Collateral reuse is optional. You can turn it on from your API keys page if your account has an active live key with the trade permission, and turn it off there at any time. We may also turn it on for an account at its request. While it is on, this section applies in addition to the rest of this Agreement.

• Shared backing. Your free cash (your wallet balance, less what your open positions and pending withdrawals commit) backs your resting buy orders in every market at once, up to that amount in each market. Without collateral reuse, each resting buy holds its own cash.
• Fills are checked against your cash. An order of yours fills only if your free cash covers it at that moment. When a fill uses cash that your other resting orders were counting on, we cancel those orders, in any market, without notice. Any of your resting orders can be cancelled this way at any time, so don't rely on one staying on the book.
• Paired positions. Up and Down contracts you hold in the same market count only for what the pair cost above $1. Selling one side of a pair is treated like a new purchase: it needs enough free cash to cover the side you keep, and is refused if you don't have it.
• Buying power and withdrawals. These subtract your open positions and the resting buys in your single largest market, not the total across markets.
• Turning it off. Each resting buy goes back to holding its own cash. We cancel the resting buys your cash can no longer cover, largest markets first. Your positions are not affected.

Collateral reuse is not credit, a loan or margin: you can never fill, owe or withdraw more than your free cash. You are responsible for your own risk controls, including when a cancellation leaves you holding a position in one market without the orders you meant to place in another. We are not liable for losses from orders cancelled or refused under this section.

We may limit how many accounts can use collateral reuse, and we may decline, suspend or turn it off for any account at any time, including when we can't read your wallet, when we suspect a breach of the Conduct section, or to protect the exchange or other users. We may change how it works under the next section.

We may change the rebate shares, the markets that earn them or any other part of this Agreement. A change to the rebates applies only to fills after it takes effect, and we will post a reduction at least 7 days before it takes effect, unless we need to act sooner to stop abuse or to comply with law. Continuing to use the API or to rest orders on the book after a change takes effect means you accept it.

We may end the rebate program, or your account's part in it, at any time. Rebates earned before the end that have not been voided under the Conduct section stay yours to claim. You can stop earning at any time by not resting orders on the book.

You are responsible for any taxes on your rebates. We may ask you for tax information and report rebates to tax authorities where the law requires. We may hold payments until you provide information we need for that.

Questions about the Trade API, the rebate program or this Agreement can be sent to hello@updown.fast.