Request limits

Requests with an API key are limited per minute for your account; heavier requests count more. Every response contains the headers X-RateLimit-Limit, X-RateLimit-Remaining and X-RateLimit-Reset, so your program can see how much is left. Over the limit you get HTTP 429 with Retry-After: wait that many seconds before the next request. Very frequent requests from one IP are also slowed down.

For live prices and order updates, use the WebSocket API instead of frequent polling. It has its own limits on connections and subscriptions, described in its documentation.

Common errors

401, timestamp_out_of_range: the clock of your server differs from ours. Sync the time (NTP) or allow a larger receive window, as described in the documentation.
401, unauthorized: the key is wrong or revoked, or the signature does not match. Check how the signature string is built and that you use the right secret.
401, signature_reused: the same signed request was sent twice. Each signature works once: sign every request, including a retry, again with a new timestamp. For a newer, safer signature format see the documentation (signature version 2).
403, forbidden: the key lacks a permission, the request comes from an IP not on the whitelist, or the action is not allowed for this key (see What can I not do through the API?).
503, withdrawals_halted: withdrawals are paused for everyone: Withdrawals are temporarily suspended.
503, trading_halted or market_halted: new orders are paused on all markets or on this market only (the market then shows trading_halted: true); cancelling works: Trading is temporarily halted.
422, market_not_started or market_ended: the market has not opened yet or its trading has ended for good (the market shows trading_phase, trading_starts_at, trading_ends_at); retrying the same order does not help: When does a new pair open, and what happens when a pair is delisted?
503, service_unavailable: a temporary problem on our side; a request that changes something (for example a withdrawal) was not carried out. Wait the seconds from Retry-After and send it again, signed anew.

Full list of errors and limits: Where is the API documentation?

API request limits and common errors