WavemiX 2026 is the annual international workshop on ultrafast EUV/X-ray science and the NEXT (COST Action CA22148) Annual Meeting. The 2026 edition will gather experimental and theoretical researchers working on- and with – free‑electron lasers (FELs) and high‑harmonic generation (HHG) sources to discuss the latest advances in non‑linear spectroscopies, attosecond physics, and ultrafast imaging.