Build ČSSZ Employee Registration (ONZ XML)

Skill: Convert hire/leave events into a ČSSZ ONZ registration

Region: Czech Republic (Česká republika) Category: Social security / payroll — ČSSZ Does: Takes employee start and end events and maps them onto the ONZ — Oznámení o nástupu do zaměstnání (skončení zaměstnání) XML for electronic submission through the ČSSZ e-Podání (VREP/APEP) / ePortál. Spec: ČSSZ ONZ XML message (current e-Podání version)

ONZ keeps the sickness-insurance register correct; it is the registration counterpart to the monthly PVPOJ premium summary (see build-cssz-pvpoj-xml). Each employee's start (přihláška), end (odhláška), or correction (oprava) is reported as an action within ONZ.

When this applies

• Report an employee's entry into employment (nástup) within 8 days of the start of participation in sickness insurance.
• Report end of employment (skončení) within 8 days of termination.
• Use a correction (oprava) action to fix a previously submitted registration.

Structure (ONZ → XML)

Header   employer IČO + variabilní symbol (VS), contact, submission date
Per employee (akce: P přihláška / O odhláška / K oprava):
   identity     jméno, příjmení, rodné číslo (or EÚ/foreign identifier + DOB)
   citizenship & permanent/contact address
   druh činnosti (activity-type code — employment / agreement DPP/DPČ / …)
   datum nástupu (start) and/or datum skončení (end)
   nemocenské pojištění participation flag and dates
   place of work / variabilní symbol of the workplace

Mapping & rules

• Identity — Czech employees by rodné číslo; foreign nationals by evidenční/foreign identifier plus date of birth and citizenship.
• Activity-type code (druh činnosti) must match the legal relationship (regular employment vs DPP/DPČ agreements), because participation thresholds and reporting differ by type.
• Sickness-insurance participation governs whether and from when registration is due; small-scale employment and agreements participate only above the statutory income thresholds — confirm the current thresholds for the period.
• Action type — P (přihláška) for a start, O (odhláška) for an end, K (oprava) to correct; an end action must reference an existing registration consistently (same rodné číslo + activity).
• Employer identification (IČO + VS) must match the data box / e-Podání certificate used to submit, and be consistent with the PVPOJ for the period.

Worked example (outline)

Employer IČO=27082440, VS=1234567890
New hire 2025-06-01 (regular employment):
  akce=P, rodné číslo=9001011234, druh činnosti=1 (zaměstnanec),
  datum nástupu=2025-06-01, nemocenské pojištění=ano
Termination 2025-09-30:
  akce=O, rodné číslo=9001011234, datum skončení=2025-09-30

Emitted as an ONZ XML and submitted via ČSSZ e-Podání (VREP/APEP) / ePortál.

Validation checklist

• Current ONZ message version used; action codes (P/O/K) correct per event
• Rodné číslo (or foreign identifier + DOB + citizenship) valid and consistent
• Druh činnosti matches the legal relationship (employment vs DPP/DPČ)
• Sickness-insurance participation/thresholds applied for the period
• Start reported within 8 days; end within 8 days; corrections reference the original
• Employer IČO + variabilní symbol consistent with the PVPOJ and the submission certificate
• Submitted via ČSSZ e-Podání (VREP/APEP) / ePortál

Last updated: 2026-06-02 — ČSSZ ONZ schema, activity-type codes, and sickness-insurance participation thresholds change; confirm the current e-Podání ONZ version, code tables, thresholds, and deadlines against current ČSSZ (cssz.cz) guidance before use.