How to build an ATS to HRIS sync

What matters here

• Trigger on the signed offer. Every day between signature and the worker record is a day onboarding cannot start.
• Leave recruitment data behind. Interview scores and rejection reasons should never reach the HR record.
• Fail loudly on an unmapped field. A silently dropped start date is discovered on somebody first day.
• Create the worker record before the start date, not on it. Provisioning needs lead time.
• Reconcile hires against worker records weekly. A signed offer with no record is somebody arriving to nothing.

Who this is for

You run people operations or HR systems. Offers are signed in the ATS and typed into the HRIS by hand, and every delay pushes provisioning later.

How it works in practice

What has to happen between an offer being signed and somebody being ready to start.

1. 1

   The signed offer fires the sync

   Not a weekly handover meeting, because every day of delay is a day onboarding cannot begin.

2. 2

   Fields map explicitly, and unmapped fails

   A dropped start date discovered on day one is the failure this prevents.

3. 3

   Recruitment data stays in the ATS

   Feedback, scorecards and rejection reasons are not HR record material.

4. 4

   The worker record is created with a future start date

   So provisioning has lead time instead of starting on the morning.

5. 5

   Onboarding provisioning triggers from that record

   One trigger, no second handover.

6. 6

   Hires and records are reconciled weekly

   Because a signed offer with no worker record is somebody arriving to nothing.

Paste these into Claude Code or Codex with the Tray Headless plugin installed. Each stage runs on its own. The systems named in them are the worked example rather than a requirement, and every prompt says so.

Once per project, run /tray-workflows:set-workspace to pick the workspace these build in. Point it at a sandbox first.

1. 1

   Start here: decide what must not cross

   The boundary matters more than the mapping.

   Headless skills build-workflow

   Copy

   Use build-workflow. The systems in play are Greenhouse and Workday, or
   whatever we run in those seats.
   
   I need the candidate and offer objects with every field, and the worker
   record with its mandatory fields and picklist values.
   
   Then decide what must not cross. My starting position: interview
   scorecards, interviewer feedback, rejection reasons, salary negotiation
   history, and any demographic data collected for diversity monitoring.
   
   Those belong to recruitment. Copying them into an HR record makes them
   visible to managers and HR business partners who should never see them,
   and once they are there nobody removes them.

2. 2

   Trigger on signature, map explicitly

   A silently dropped start date is discovered on somebody first day.

   Headless skills build-workflow

   Copy

   Use build-workflow. Trigger on the offer reaching signed, not on a stage
   change or a weekly export.
   
   Map every field explicitly: legal name, preferred name, personal email
   for pre-start contact, start date, job profile, level, department, cost
   centre, manager, location, employment type, and compensation.
   
   Fail loudly on anything unmapped or invalid. Do not create a partial
   worker record and do not silently drop a field.
   
   A dropped start date produces somebody arriving with no provisioning. A
   dropped cost centre produces a payroll problem in the first cycle. Both
   are discovered by the new joiner rather than by us, which is the worst
   way to find out.

   Picklist mismatches are the most common failure. The ATS job title is free text and the HRIS job profile is a controlled list, and they will not agree.

3. 3

   Create the record early, with a future start date

   Provisioning needs lead time it currently does not get.

   Copy

   Create the worker record as soon as the offer is signed, with a future
   start date, rather than on the day they start.
   
   That record is what onboarding provisioning schedules against: hardware
   ordered, identity created and disabled, access sequenced against day one.
   Every day earlier it exists is a day of lead time provisioning gets.
   
   Handle the pre-start period explicitly: the person is not an employee
   yet, they should not appear in the directory, and they should not receive
   company communications until their start date.
   
   Where the HRIS cannot hold a pre-start worker, use the ATS record as the
   provisioning trigger and reconcile once the worker record exists.

4. 4

   Handle the changes that happen before day one

   Offers change more often than anybody plans for.

   Headless skills tray-gotchas

   Copy

   Use tray-gotchas, then handle these:
   
     Start date moves, which is common. Update the record and replan every
     scheduled provisioning step instead of firing the missed ones.
     Offer withdrawn or declined after acceptance. Remove the worker record,
     reverse anything provisioned, and confirm the reversal.
     Compensation renegotiated after signing. Update, and flag for payroll
     if it crosses a threshold.
     A rehire, where a worker record already exists. Never create a
     duplicate, and never silently reactivate the old record with its
     historical access.
     A contractor converting to employee, which is a change instead of a
     new hire and needs their tenure preserved.

5. 5

   Reconcile weekly

   A signed offer with no worker record is somebody arriving to nothing.

   Copy

   Reconcile weekly between the ATS and the HRIS:
   
     Signed offers with no worker record. This should be zero and it is the
     one that produces a person arriving to nothing.
     Worker records with no corresponding hire, which is usually a manual
     creation bypassing the process
     Start dates that disagree between systems
     Anybody starting in the next fortnight whose provisioning has not begun
   
   Report: time from signature to worker record, time from signature to
   provisioning complete, sync failures by field, and first-day incidents
   traced back to a sync failure.
   
   That last number is the one that matters to the new joiner, and it is the
   only one anybody outside the team ever hears about.

6. 6

   Prove it works, then hand the mapping over

   Because job profiles and levels change constantly.

   Copy

   Run the per-step schema checks and the whole-workflow audit before this
   touches production. Run it alongside the manual process for a few hires
   and compare every field.
   
   Then open the same workflow in Tray Build so people operations can
   maintain the field mapping and the job profile translation in the visual
   canvas. New roles and levels appear constantly and none should need an
   engineer.

What it connects to

Recruitment hands over to HR, and provisioning waits on the result.

Named systems are the ones most teams run, not the only ones that work. Each is an authentication in your Tray workspace, referenced by name, so the workflow never holds a credential. Where we have a connector page, the name links to it.

Questions people ask

Related guides