Prices in GBP. Verified monthly. Always check the provider's site for the latest.
Pros & cons
Grammarly
Pros
+SOC 2 Type II and ISO 27001 certified — strongest compliance in the writing category
+Works across browser, desktop, Word, Google Docs, and email with one install
+Pro tier confirmed at £10/mo in GBP — transparent UK pricing
+Explicit opt-out from AI model training available in account settings
Cons
−Trains on user writing by default — opt-out required
−GDPR compliance not explicitly confirmed on accessed official pages
−Free AI prompt limit (100/mo) may feel restrictive for daily users
Leonardo.ai
Pros
+GDPR compliant — UK GDPR and EU GDPR explicitly listed in ToS
+Free tier confirmed in ToS — usable without payment
+API available with separate billing for developer integration
+Wide range of fine-tuned models for games, concept art, and illustration
Cons
−Pricing not verified — official site inaccessible to automated tools; check leonardo.ai for current plans
−Free user content used to train AI models — paid private content exempt
−SOC2 and ISO 27001 not confirmed from official sources
Our take— Grammarly wins
Based on our comparison of published pricing, features, and compliance data, Grammarly scores 8.1/10 to Leonardo.ai's 7.6/10. Grammarly pulls ahead with ISO 27001 certification and multi-factor authentication. Leonardo.ai counters with GDPR compliance. Pick Grammarly if ISO 27001 certification matters; pick Leonardo.ai if GDPR compliance matters.