May I record a customer service conversation as evidence?

Customer service recording = textbook scenario for one-party consent. Sr Art. 139a only prohibits covert recordings by third parties not party to the conversation. You participate yourself = legal. Practical tips: (1) Mention recording at start of call — "I'm recording this as evidence for my file". Not required but good practice + improves dynamics. (2) Save file securely — cloud backup + timestamp. (3) Use in dispute: recording can provide evidence for damages claim, ACM complaint, civil case. Especially useful for promises later denied. (4) DO NOT publish without consent of customer service rep — GDPR breach + portrait law. Business side: businesses may also record customer service calls ("for quality and training") under conditions — privacy statement + opt-out offered + retention. Recording apps: Apple iOS has built-in call recording since iOS 18 (with announcement). Android (Pixel) too. External apps Cube ACR, Truecaller. Test beforehand whether recording stores cleanly. Disclaimer: on commercial sales recording is extra valuable — promises are often disputed later.