The unlock_achievement event
unlock_achievement is a GA4 recommended gaming event you fire when a player earns an achievement, identified by an achievement_id. Achievements are engagement and goal-completion signals: which ones unlock often, which are rarely reached, and how unlocking relates to retention. It complements progression events by capturing discrete milestones rather than continuous leveling.
What this means
unlock_achievement is a GA4 recommended gaming event. You fire it when a player unlocks an achievement, passing achievement_id to identify which one. It captures discrete accomplishments, complementing the continuous progression that level_up tracks.
Because it is a recommended event, GA4 recognises it and includes it in gaming-oriented analysis.
Achievement analysis
Counting unlock_achievement by achievement_id shows which milestones players reach and which they miss. An achievement almost no one unlocks may be too difficult or hidden; one nearly everyone unlocks may be trivial. Correlating unlocks with retention shows which milestones predict ongoing engagement.
- achievement_id: identifies the unlocked achievement
- Captures discrete milestones, not continuous leveling
- Correlate unlock rates with retention
How it appears in analytics and logs
An unlock_achievement event means a player reached a defined milestone. Rarely-unlocked achievements may be too hard or poorly surfaced.
Diagnostic use case
Measure which achievements players unlock to understand engagement milestones and goal completion.
What WebmasterID can help detect
WebmasterID can record milestone events first-party so achievement engagement is measurable without cross-site tracking.
Common mistakes
- Reusing achievement_id values across different achievements.
- Firing the event on view rather than unlock.
- Embedding player identity in achievement_id.
Privacy and accuracy notes
achievement_id names a game milestone, not a person. Keep player PII out of the parameter. Educational, not legal advice.
Related pages
- The level_up event
level_up is a GA4 recommended gaming event for character or account progression — distinct from completing a stage. You fire it when a player advances a level, passing a level number and optionally a character parameter. It measures long-run progression and retention depth, answering how far players advance rather than whether they finished a single stage.
- The post_score event
post_score is a GA4 recommended gaming event for recording a player's score. You fire it when a score is achieved or submitted, passing a score value and optionally level and character. It supports analysis of skill distribution, leaderboard behavior, and how scoring correlates with progression and monetisation events across your player base.
- The tutorial_begin and tutorial_complete events
tutorial_begin and tutorial_complete are a paired set of GA4 recommended gaming events that bracket onboarding. You fire tutorial_begin when a player starts the tutorial and tutorial_complete when they finish. The ratio between them is a direct onboarding-completion metric — one of the strongest early predictors of whether new players stick around, making this pair central to retention analysis.
- Event Explorer
See achievement unlock rates.
Sources and verification notes
Last reviewed 2026-06-24. Facts are checked against primary/official sources where available; uncertain specifics are marked “Data not yet verified” rather than guessed.