[{"data":1,"prerenderedAt":68},["ShallowReactive",2],{"\u002Fglossary\u002Frtt-0-zero-round-trip-time":3,"\u002Fglossary\u002Frtt-0-zero-round-trip-time:related":51},{"id":4,"title":5,"author":6,"authorImage":7,"body":8,"category":35,"date":36,"description":37,"draft":38,"extension":39,"letter":40,"meta":41,"navigation":42,"path":43,"readTime":44,"related":45,"seo":46,"stem":48,"term":49,"__hash__":50},"glossary\u002Fglossary\u002Frtt-0-zero-round-trip-time.md","RTT-0 (Zero Round-Trip Time)","Fabian Krumbholz","\u002Fimages\u002Fauthors\u002Ffabian-krumbholz.webp",{"type":9,"value":10,"toc":31},"minimark",[11],[12,13,14,18,19,22,23,26,27,30],"p",{},[15,16,17],"strong",{},"0-RTT"," (Zero Round-Trip Time Resumption) is a high-performance feature of modern network protocols like TLS 1.3 and ",[15,20,21],{},"HTTP\u002F3",". It allows a browser that has recently connected to a server to send application data in its very first message on a subsequent visit, without waiting for the security handshake to complete. This effectively eliminates one full ",[15,24,25],{},"Round Trip Time (RTT)"," from the connection setup, significantly speeding up the ",[15,28,29],{},"Time To First Byte (TTFB)",", especially on mobile networks.",{"title":32,"searchDepth":33,"depth":33,"links":34},"",2,[],null,"April 8, 2026","0-RTT (Zero Round-Trip Time Resumption) is a high-performance feature of modern network protocols like TLS 1.3 and HTTP\u002F3.",false,"md","R",{},true,"\u002Fglossary\u002Frtt-0-zero-round-trip-time","1 min read",[],{"title":47,"description":37},"RTT-0 (Zero Round-Trip Time): Definition | Web Performance Glossary","glossary\u002Frtt-0-zero-round-trip-time","RTT-0","S5pav-SBDDj17rbeEOUM_YBy7_8HlZqJ3pOEBJM_vc4",[52,56,60,64],{"path":53,"title":54,"description":55,"letter":40},"\u002Fglossary\u002Froi-return-on-investment","ROI (Return on Investment)","ROI is a business metric used to evaluate the profitability of an investment by comparing the net profit to the cost of the investment. It is typically expressed as a percentage.",{"path":57,"title":58,"description":59,"letter":40},"\u002Fglossary\u002Frtt-round-trip-time","RTT (Round Trip Time)","RTT stands for Round Trip Time and is a fundamental networking metric. It measures the total time it takes for a data packet to travel from a source (like a user's browser) to a destination (a serv…",{"path":61,"title":62,"description":63,"letter":40},"\u002Fglossary\u002Freal-user-monitoring-rum","Real User Monitoring (RUM)","See Field Data.",{"path":65,"title":66,"description":67,"letter":40},"\u002Fglossary\u002Fredirect-time","Redirect Time","A redirect is a response from a server that automatically forwards a user from one URL to another. While sometimes necessary (e.g., for tracking or moving content), redirects are very harmful to performance.",1787756715874]