sofortig
immediate
Describes something that happens or is required without any delay or waiting time.
Der Fehler erfordert eine sofortige Korrektur, bevor das System ausfällt.
The error requires an immediate correction before the system fails.

immediate
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immediate
Describes something that happens or is required without any delay or waiting time.
Der Fehler erfordert eine sofortige Korrektur, bevor das System ausfällt.
The error requires an immediate correction before the system fails.

'Sofortig' (immediate) is the adjective corresponding to the adverb 'sofort' (immediately). If you know that 'sofort' means 'immediately', you can easily derive the meaning of 'sofortig' as 'immediate'.
Bitte geben Sie mir sofort Bescheid.
Please let me know immediately.
This adjective is used almost exclusively before a noun (attributive use). Using it after a verb like 'sein' (to be) (predicative use) is very rare and sounds unnatural or very formal.
Wir erwarten eine sofortige Reaktion der Regierung.
We expect an immediate reaction from the government.
'Sofortig' (immediate) is often used in formal, official, or business contexts to emphasize urgency. It is typical in instructions, warnings, or contracts.
Bei Vertragsbruch ist eine sofortige Kündigung möglich.
In the event of a breach of contract, immediate termination is possible.
direct
'direkt' and 'sofortig' can both mean that something happens without delay. 'direkt' is very common in everyday language and can be used as an adjective or adverbially: you set off directly, or you get a direct answer. 'sofortig' is an adjective and usually comes before a noun, for example 'sofortige Hilfe' (immediate help) or 'sofortige Zahlung' (immediate payment). It sounds more official or written. The words can be confused because both express temporal closeness. In normal conversations, 'direkt' or 'sofort' is often more natural; 'sofortig' fits mainly before formal nouns.

Bei einem Wasserrohrbruch ist sofortige Hilfe wichtig.
When a water pipe bursts, immediate help is important.
Nach dem Training fahre ich direkt nach Hause.
After training, I go straight home.