Use session_id for one Call-ID, or session_ids (non-empty, max 50) for an OR filter across sessions. When session_ids is set it takes precedence over session_id. Supported on messages, qos, logs, callinfo, events, sub, hepsub, and export endpoints; responses include session_id on rows for grouping. For SIP call (proto_type=1, event_type=call), POST /transactions/callinfo returns one summary object per Call-ID (ringing_seconds, call_duration_seconds, codecs, UAC/UAS, setup delays, status, from_party, ruri_party, methods_distribution for the legacy methods chart, etc.).