Low-frequency mutations provide valuable insights in various fields, including drug resistance identification, cancer and infectious disease research. One promising strategy to enhance the sensitivity and specificity of mutation detection is the incorporation of unique molecular identifiers (UMIs) during polymerase chain reaction (PCR) amplification and before deep sequencing. However, conventional methods for UMI incorporation often necessitate multiple labor-intensive steps. spotPCR (Specific Primer Limited Unique Molecular Identifier Tagging PCR) overcomes these challenges, streamlining the UMI tagging process.