How does bail actually work?
Release from custody subject to conditions and an obligation to return — and the persistent misunderstanding is that it involves paying money, which in most of the world it does not.
The purpose. Bail balances the presumption of innocence and the person's liberty against the risks of them failing to attend, committing further offences, or interfering with witnesses. It is not a judgement on guilt.
The two stages:
Police bail, where someone is released from a police station while an investigation continues, with or without conditions, and either to return on a date or — under "released under investigation" arrangements in some systems — without a return date at all, which has been criticised for leaving people in limbo indefinitely.
Court bail, granted or refused at a hearing, and continuing between hearings.
The conditions commonly imposed: residence at a specified address; a curfew, sometimes electronically monitored; reporting to a police station; surrendering a passport; not contacting named people; exclusion from defined areas; and a surety — a person who promises a sum of money that becomes payable if the defendant absconds.
Why money bail is different in the United States. The commercial bail bond system, where a defendant pays a non-refundable fee to a bondsman who guarantees the full amount, is unusual internationally and heavily criticised — it effectively conditions liberty on ability to pay, and reform has been a sustained political issue. Most other countries use conditions rather than cash.
When bail is refused: where there are substantial grounds to believe the person would fail to surrender, commit further offences or obstruct justice; for their own protection; or for certain serious offences where refusal is the starting point. Refusal means remand in custody before any trial, which has significant consequences for employment, housing and family.
Breaching bail conditions is itself an offence in many systems and generally results in arrest and a fresh hearing.
Failing to attend is a separate offence and makes future bail far less likely.
General information, not legal advice; systems differ substantially by country.