# ATXP account top-up checkout
Version: agent_checkout_v1
Purpose: Add prepaid credits to an ATXP account.
Consent: Only complete checkout when the user has explicitly asked to buy or add credits.
Return behavior: After successful checkout, return to the provided return_url when present and safe.
Preserve fields: top_up_session_id, product, source, surface, return_url, experiment_key, experiment_variant, posthog_distinct_id, payment_link_id, pricing_region, pricing_pack_set, ad_pressure_context_id, creative_id, creative_brand, creative_campaign, creative_surface, creative_pack_key, creative_archetype, creative_format, creative_aspect_ratio, browser_country_code, cta_variant, remove_ads_duration_hours, localized_pricing, checkout_channel, agent_instruction_version