The acronym IDX may refer to:.idx file extension, used by various programs to represent an index of some kind, commonly used by the DirectVobSub add-on for subtitle files ID Experts Holdings, Inc., data breach response company owned by ZeroFox IDX Systems, software company, portions now owned by GE and athenahealth Project IDX, an online integrated development environment by Google Indonesia AirAsia X, former airline with ICAO airline code IDX Indonesia Stock Exchange IDX Channel, Indonesian channel jointly owned by Indonesia Stock Exchange and Trans Media IDX Composite, Indonesia Stock Exchange composite index Intact dilation and extraction, abortion procedure Internet Data Exchange