Aster Market Data API

What it is

Aster is a perpetual-futures DEX that grew out of a December 2024 merger between APX Finance and Astherus and took the Aster name on 31 March 2025. The venue is out of scope here — this catalogue does not list places to trade. What is in scope is the part of its API that answers without a key: the market-data half of the futures API at fapi.asterdex.com, the spot API at sapi.asterdex.com, and their websocket streams.

Anyone who has written against Binance USD-M futures already knows this API. The paths, the parameters, the twelve-element kline arrays, the X-MBX-USED-WEIGHT-1M header on every response — all of it matches. That is the practical case for it: a Binance-shaped client pointed at a new base URL gets order books, candles in three price flavours (last, index and mark), funding history and configuration, 24-hour tickers, and liquidation streams from a decentralised venue.

The reason to reach for it over an aggregator is what an aggregator does not carry. One example is indexreferences: it returns the source exchanges and weights behind each contract's index price. For BTCUSDT on 24 September 2026 that was Binance at 43.5%, OKX and Coinbase at 13.0% each, then Bybit, Bitget, KuCoin, MEXC and Gate. That tells you how much of this venue's price is really Binance's price, and no second-hand feed publishes it.

Pricing

There is nothing to buy. No tier, no quota and no history window is unlocked by paying Aster anything, and nothing in the market section asks for a wallet signature.

The one recent change runs the other way and is worth reading precisely. Since 1 September 2026, authenticated V3 endpoints — account, orders, trades — return {"code":-5050,"msg":"This function can only be used after deposit"} until the main wallet has deposited. The changelog lists public market data among the things that rule does not touch, so it gates trading rather than data. It does mean that anything account-shaped, including your own fill history, now sits behind a funded wallet.

Data & coverage

On 24 September 2026 the futures exchangeInfo listed 608 symbols, 584 of them trading and 19 settling, all perpetual and almost all quoted in USDT, with 15 in USD1. The spot host listed 71 pairs. 115 of the trading perpetuals are tagged as stocks — US names such as AAPL, TSLA, NVDA and QQQ, plus Hong Kong and Korean listings, some quoted in USD1. Their mark price switches to an EWMA-smoothed mode overnight, at weekends and on holidays, so off-hours candles on those contracts are a smoothed thin-market price and not a reading of the underlying stock.

Rate limits are per IP, and the documentation says so in bold. The futures host allows 2,400 request weight per minute and the spot host 6,000. An order-book request costs 2 weight at 50 levels and 20 at 1,000 levels. Keep sending after a 429 and the IP is banned with HTTP 418, for anything from 2 minutes to 3 days on repeat offences. A fleet behind one NAT shares one budget. Websockets live at fstream.asterdex.com, allow 200 streams and 10 incoming messages a second per connection, and drop every connection at 24 hours.

History goes back past the Aster name. Asking for BTCUSDT daily candles from epoch returns 1 September 2021 first. Funding history starts 27 August 2021, and aggTrades returns trade id 1 on 29 August 2021, so the aggregate tape of the oldest contracts is retrievable from the start, page by page, without a key. In the V3 paths historicalTrades also answers without a key; its V1 twin still refuses with API-key format invalid. Spot history is short: BTCUSDT candles begin on 11 September 2025.

Open interest is a current number only. openInterest answers with a snapshot but is not in either version of the documentation, and the Binance-style futures/data/openInterestHist path returns 404. If you want an open-interest time series for Aster, you have to record it yourself or buy it from somebody who has.

Liquidations are sampled, not complete. The forceOrder streams push at most the latest liquidation per symbol per second — the Binance convention, and the same caveat. Summing the stream undercounts in exactly the minutes that matter.

Integrations

Aster's GitHub organisation publishes a first-party MCP server, asterdex/aster-mcp — Python, version 0.1.0, marked alpha, last committed on 6 March 2026. Its ticker, order-book, kline, funding and exchange-info tools take no account, so an agent can read market data with no credentials configured. Two caveats. The repository has no LICENSE file, only an MIT declaration in pyproject.toml. And it is not on PyPI, so installation is from the git URL.

The Python connector, aster-connector-python, is MIT-licensed and was last committed on 31 March 2025, which predates V3 signing. Its README says pip install aster-connector-python. PyPI had no package by that name on 24 September 2026, so the documented install command fails. For public data that hardly matters: any Binance futures client with a configurable base URL does the same job.

CCXT carries Aster and routes orders there under a builder programme that adds 1 basis point by default. The market-data side is free in CCXT as it is here.

Limitations

The terms put the United States, Canada and the United Kingdom out of bounds, APIs included. Aster's Terms and Conditions, last updated 25 February 2026, define the Services to include "APIs" and prohibit their use by anyone located in the US, Canada, the UK, China, North Korea, Russia, Ukraine, Cuba, Iran, Venezuela or Syria. Whether the public endpoints enforce that with an IP block, the way Bybit's do, was not tested — these calls were made from Turkey. Either way, the prohibition is in the contract whether or not a 403 enforces it.

The same terms say nothing permissive about the data. Section 6.1 forbids reproducing, distributing, republishing, downloading or storing "any of the material on our platform" without prior written consent. Section 6.2 forbids "any automated means, including bots, scrapers, or spiders" without express permission. Neither clause mentions the public API, and there is no separate API licence. Publishing the API does not obviously count as permission to store and redistribute what it returns. For a commercial product built on this data, get that permission in writing.

The public book is not the whole book. Aster offers hidden orders, which "operate within the existing order book" but never appear on it, and whose resulting positions are "excluded from all public data". A book rebuilt from depth and the diff stream will not reproduce every fill, and volume at a price can print where the visible book showed nothing.

Stock perpetuals are not stock data. They are derivative contracts priced off an index built partly from the Pyth oracle, smoothed off-hours and settled in USDT. They are useful for studying how a crypto venue trades equities around the clock. They are no substitute for a stock-market feed.

Version churn is real. V1 key creation stopped on 25 March 2026, the V3 signing scheme is a different protocol, and the documentation repository received fixes from an internal audit as recently as 22 September 2026. Public paths exist under both /fapi/v1/ and /fapi/v3/ today; build against V3.

Alternatives

The structural choice is venue-direct against recorded-by-someone-else. Tardis.dev began capturing Aster on 23 August 2026, so tick-level book history for this venue starts there and nowhere earlier. Aster itself keeps no historical depth at all. For cross-venue derivatives telemetry that includes Aster alongside the centralised perps — open interest over time, funding compared across venues, liquidation heatmaps — CoinGlass and Coinalyze carry it and have already done the recording.

If the reason you are here is the Binance-shaped API rather than Aster in particular, the original is next door: Binance's own market data API is deeper, older and equally keyless, with the same per-IP ban mechanics.