# Perpetual futures

Also written perpetual swap, perpetual contract, perps.

*https://cryptomarkets.tools/glossary/perpetual-futures · next to Crypto Trading Terminals*

**Definition:** A futures contract with no expiry date. Nothing forces it to converge on spot at delivery, so a periodic funding payment between longs and shorts pulls its price toward an index instead. Each venue lists its own: a BTC perpetual on two exchanges is two instruments, with separate order books, indices, margin currencies and contract sizes, and the price it trades at is not the spot price.

Three cards in four in this catalogue list perpetuals in their coverage, which makes it the most
common derivative here and the one the coverage field says least about. The word names a contract
shape. Which contract — which venue, which margin currency, which index — is what a reader needs and
the flag does not carry.

## How it works

A dated future converges on spot because at expiry it settles against the underlying. A perpetual
has no expiry, so nothing forces that convergence; the [funding rate](https://cryptomarkets.tools/glossary/funding-rate) is the
substitute. When the contract trades above its index, longs pay shorts, and the payment pulls the
price back. OKX's own guide puts it in one sentence: perpetual futures "do not have an expiration
date", and the funding mechanism exists "to ensure the futures' prices and index prices converge
periodically". Converge periodically, not stay equal — the gap between a perpetual and spot is the
basis, and it is real.

Every perpetual therefore has at least three prices attached to it: the last trade on its own book,
the index it is pulled toward (a weighted spot price from other exchanges), and a
[mark price](https://cryptomarkets.tools/glossary/mark-price) the venue computes from both to value positions. Margin is posted
against the position, and when it runs short the venue closes it — a
[liquidation](https://cryptomarkets.tools/glossary/liquidation), which is the second cash flow a perpetual has that spot does
not.

**Linear and inverse are two different contracts.** A linear perpetual is sized in the coin and
settled in the quote currency: OKX's USDT-margined BTC contract is 0.01 BTC and settles in USDT. An
inverse one is sized in dollars and margined and settled in the coin: OKX's crypto-margined
contract is 100 US dollars and settles in BTC, so its profit and loss in BTC is not a straight line
in the dollar price. Hyperliquid documents its contracts as linear perpetuals with the oracle
price in USDT and the collateral in USDC — a third combination.

**The names are not standard either.** CCXT's market structure types it `swap`, "for perpetual swap
futures that don't have a delivery date", and puts the settlement currency after a colon:
`BTC/USDT:USDT` is a linear perpetual funded in USDT and `BTC/USDT:BTC` an inverse one funded in BTC.
Bybit's market endpoints take a `category` of `spot`, `linear` or `inverse`, and the word
"perpetual" appears nowhere in the parameter. Kaiko's instrument class is `perpetual-future`.

**In the United States a perpetual is a five-year future.** Coinbase Derivatives certified its nano
Bitcoin Perp Style Futures with the CFTC on 26 June 2025 as a five-year, cash-settled contract, the
first expiring on the third Friday of December 2030, with only one contract listed for any five-year
period. Funding is calculated every hour by the clearing house and settled through its mid-day and
end-of-day margin runs. It behaves like a perpetual and is legally a dated future, which is why a
vendor's "perpetuals" filter may or may not contain it.

## Why it matters here

**A perpetual's price is not the spot price.** A chart or a price API built from perpetual trades
carries the basis in it, and during a squeeze the basis is the move. Check which market a series
came from before comparing it with anything. The ticker will not tell you: on Binance `BTCUSDT`
names both the spot pair and the USDⓈ-M perpetual, and on Bybit's kline endpoint omitting
`category` returns `linear` by default — the perpetual, not spot.
[Where the Bitcoin price comes from](https://cryptomarkets.tools/guides/where-the-bitcoin-price-comes-from) is the longer
version of why two "BTC prices" disagree.

**One venue's perpetual is not another's.** Funding interval, contract size, margin currency and the
index constituents are all set per venue, and sometimes per symbol. An aggregate that sums
perpetuals across exchanges has converted at least some of them, which is the problem
[open interest](https://cryptomarkets.tools/glossary/open-interest) runs into at full size. A card that says it covers
perpetuals should also say which venues and whether it keeps linear and inverse apart. The venues'
own APIs — [Binance](https://cryptomarkets.tools/tools/binance-api), [Bybit](https://cryptomarkets.tools/tools/bybit-api), [OKX](https://cryptomarkets.tools/tools/okx-api) —
answer these questions for one book at a time. [CCXT](https://cryptomarkets.tools/tools/ccxt) answers them in one naming
scheme across many.

**Decentralised perpetuals are the same contract on a different stack.** Hyperliquid, dYdX and Aster
list perpetuals with the same funding-and-index mechanics, but the data arrives through the venue's
own API, indexer or Binance-shaped endpoints rather than through the aggregators most cards were built
around. See the [Hyperliquid SDK](https://cryptomarkets.tools/tools/hyperliquid-python-sdk), the
[dYdX v4 clients](https://cryptomarkets.tools/tools/dydx-v4-clients) and [Aster's API](https://cryptomarkets.tools/tools/aster-api). Aster also shows the
shape stretching past crypto: more than a hundred of its perpetuals are tagged as stocks, and they
keep trading after the underlying has closed.
[What a tokenized stock is](https://cryptomarkets.tools/guides/what-a-tokenized-stock-is) covers what that weekend price is.

**A perpetual treated as spot is a different instrument.** A backtest that loads perpetual candles
and charges neither funding nor liquidation has deleted both cash flows the position has.
[What a crypto backtest silently assumes](https://cryptomarkets.tools/guides/what-a-crypto-backtest-assumes) goes through which
engines charge them. For the data itself, the how-tos on
[funding and open interest](https://cryptomarkets.tools/how-to/get-funding-and-open-interest) and on
[watching liquidations](https://cryptomarkets.tools/how-to/watch-liquidations) take the two perpetual-only series one at a
time.

## Where you will meet this

- [CCXT](https://cryptomarkets.tools/tools/ccxt.md)
- [Bybit Market Data API](https://cryptomarkets.tools/tools/bybit-api.md)
- [Binance Market Data API](https://cryptomarkets.tools/tools/binance-api.md)
- [OKX Market Data API](https://cryptomarkets.tools/tools/okx-api.md)
- [Kaiko Market Data API](https://cryptomarkets.tools/tools/kaiko.md)
- [Aster Market Data API](https://cryptomarkets.tools/tools/aster-api.md)
- [Hyperliquid Python SDK](https://cryptomarkets.tools/tools/hyperliquid-python-sdk.md)
- [dYdX v4 Clients](https://cryptomarkets.tools/tools/dydx-v4-clients.md)
- [Allium](https://cryptomarkets.tools/tools/allium.md)
- [Backtesting.py](https://cryptomarkets.tools/tools/backtesting-py.md)
- [Bitsgap](https://cryptomarkets.tools/tools/bitsgap.md)
- [CoinGlass](https://cryptomarkets.tools/tools/coinglass-web.md)

## FAQ

### Is a perpetual swap the same thing as perpetual futures?

Yes. OKX's help centre uses both names for the same product, CCXT gives it the market type swap, Kaiko files it under the instrument class perpetual-future, and Bybit's API does not use the word at all, sorting contracts into linear and inverse. Four names, one contract shape. What differs between them is the venue, not the word.

### What is the difference between a linear and an inverse perpetual?

The currency the contract is margined and settled in. OKX's USDT-margined perpetual is sized at 0.01 BTC and settles in USDT; its crypto-margined one is sized at 100 US dollars and settles in BTC. CCXT's symbols carry the difference after a colon — BTC/USDT:USDT is linear, BTC/USDT:BTC is inverse — so two symbols that look alike can be different contracts with different books.

### Can US traders use perpetual futures?

Not the offshore kind. What exists on a CFTC-regulated exchange is a long-dated future built to behave like one: Coinbase Derivatives' nano Bitcoin Perp Style Futures, certified on 26 June 2025, is a five-year cash-settled contract whose first expiry is the third Friday of December 2030, with funding calculated hourly and settled through the clearing house's twice-daily margin runs.

## Sources

1. [OKX Perpetual Futures Guide](https://www.okx.com/en-us/help/i-perpetual-swaps) — OKX, 2026-08-27
2. [Contract specifications](https://hyperliquid.gitbook.io/hyperliquid-docs/trading/contract-specifications) — Hyperliquid, read 2026-09-26
3. [Get Kline, V5 market endpoints](https://bybit-exchange.github.io/docs/v5/market/kline) — Bybit, read 2026-09-26
4. [Manual — market structure and contract naming](https://github.com/ccxt/ccxt/wiki/Manual) — CCXT, read 2026-09-26
5. [Submission #2025-32: CFTC Regulation 40.2(a) certification, listing of the nano Bitcoin Perp Style Futures](https://www.cftc.gov/sites/default/files/filings/ptc/25/06/ptc06262524818.pdf) — Coinbase Derivatives, filed with the U.S. Commodity Futures Trading Commission, 2025-06-26

*Last updated 2026-09-26. A reference page, corrected in place — not a dated post.*