Many companies keep an ATS upstream or a legacy HRIS alongside Illizeo. Here is how to make them coexist — without a dedicated connector, because none exists.
Coexistence strategies #
| What you want to do | The actual means |
|---|---|
| Create employees hired in an ATS | The REST API (employee write ability), or a file import |
| Feed a third-party HRIS from Illizeo | The REST API in read, polled by a scheduled job on your side, or exports |
| Keep a directory up to date | The Microsoft Entra ID connector, which provisions from Illizeo |
| Pick up a change as it happens | Not possible as things stand: no webhook. You poll. |
There is no pre-built connector to a third-party ATS or HRIS. Illizeo’s eight connectors are: Microsoft 365, Google, Zoom, DocuSign, Adobe Sign, UgoSign, Slack and Microsoft Entra ID. No Workday, no SuccessFactors, no Greenhouse.
Step-by-step #
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Name the source of truth, field by field #
This is the only decision that really matters. For each piece of data — identity, contract, pay, reporting line — one system decides and the other follows. Two systems writing the same field always diverge in the end.
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Choose direction and frequency #
With no events, synchronisation is periodic. A nightly pass covers most reference data; save frequent passes for what genuinely changes often.
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Create one token per integration #
One token per system, with only the abilities it needs. That makes removing a system trivial: delete its token.
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Keep an identifier mapping #
On your side, keep the link between the Illizeo id and the third-party one. Do not rely on the email address: it changes.
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Handle rejections explicitly #
A refused write comes back with an error code and a request id. Log them: a silent synchronisation that fails every other night is worse than no synchronisation.
Supported ATS / HRIS connectors #
| Type | Tools |
|---|---|
| Recruitment ATS | Greenhouse, Lever, Welcome Kit, Lucca, Teamtailor |
| Legacy HRIS | Workday, SAP SuccessFactors, Cornerstone |
| Specialised payroll | Sage, Cegid, ADP, Silae |
| Performance / Reviews | Lattice, 15Five, Culture Amp |
| Learning / LMS | 360Learning, EdCast, Cornerstone Learning |
FAQ #
Is there a Workday or SuccessFactors connector?
No. Coexistence goes through the REST API, or through file imports and exports.
And an ATS connector?
Also no. If your ATS can call a REST API, it can create the employee in Illizeo at hiring time; otherwise it is an import.
Can double entry be avoided?
Yes, but only by settling the source of truth field by field. No tool substitutes for that decision.
What frequency for an organisational reference?
Once a night. An org chart does not move every five minutes, and a daily pass leaves a window to fix things before an error spreads.
How do we migrate gradually?
Switch field by field rather than module by module, and keep a written record of who decides what at each stage. The hybrid period is managed by that document, not by the tool.
What does not exist #
No pre-built ATS or HRIS connector. No configurable field-mapping engine inside Illizeo. No automatic conflict resolution. No two-way synchronisation driven from Illizeo: outside the Entra directory, it is your system that calls the API.
