IRS 1099-NEC / 1099-MISC / 1099-K IRIS e-file: TIN validation, per-box thresholds, IRIS CSV + A2A XML for TY2026, corrections
US SSA EFW2 W-2 e-file generator for Business Services Online: RA/RE/RW/RT/RF records, state RS records, EIN/SSN validation, FICA wage derivation — BYOK.