Deltek and Paychex integration

What moves between them

The main flow runs from Paychex into Deltek. ml-connector reads Paychex workers and writes them as Deltek employees so hires, terminations, and rehires stay aligned, and after each processed payroll it reads the Paychex checks and posts the labor cost into Deltek as journal entries mapped to the matching projects, organizations, and accounts. Reference data such as organization units and cost centers is aligned so every payroll journal line lands on a valid Deltek dimension. Paychex holds no GL or AP documents, so ml-connector treats it as the workforce and payroll source and never writes financial entries back into Paychex.

How ml-connector handles it

ml-connector stores both credential sets encrypted. On the Paychex side it acquires a client credentials token, re-acquires it proactively before expiry since no refresh token is issued, and resolves companyId from GET companies before any worker or check call. On the Deltek side it accepts the full Vantagepoint tenant URL per customer, runs the OAuth2 password grant, and refreshes the bearer token when a call returns 401. Paychex webhooks for new, demographic, compensation, and employment changes carry no data, so each notification triggers a GET to fetch the current worker before it is written to Deltek as an employee. Organizations and cost centers are mapped first so every journal line references a valid Deltek project and account. Deltek has no idempotency key, so ml-connector checks for an existing employee or journal entry before posting to avoid duplicates, and Paychex offset pagination can skip or duplicate rows mid-crawl, so the per-page ETag is carried forward. Paychex rate limits return HTTP 429 with a Retry-After header, so ml-connector backs off and retries, and every record carries a full audit trail and can be replayed if a downstream call fails.

A real-world example

A mid-sized architecture and engineering firm of about 300 staff runs Deltek Vantagepoint for projects, billing, and accounting, and uses Paychex Flex for payroll and HR across three offices. Before the integration, an administrator added each new hire to both systems by hand and the finance team exported the payroll register every pay period and re-entered the labor totals into Deltek by project, then spent the start of month-end close chasing differences between headcount and the labor accounts. With Deltek and Paychex connected, new workers flow into Deltek as employees, each payroll posts as a journal entry allocated to the right projects and organizations, and close starts with labor already reconciled.

What you can do

• •Create and update Deltek employees from Paychex workers so hires, terminations, and rehires stay aligned.
• •Post labor cost from each processed Paychex payroll into Deltek as journal entries against the correct projects and accounts.
• •Map Paychex organization units and cost centers to Deltek organizations so payroll lands on valid dimensions.
• •Authenticate Paychex with its OAuth2 client credentials token and Deltek with its tenant-specific password grant.
• •React to Paychex worker webhooks by fetching the current record first, with retries and a full audit trail on every record.

Questions

Which direction does data move between Deltek and Paychex?

The main flow is Paychex into Deltek. Worker records and payroll labor cost move from Paychex into Deltek as employees and journal entries, while organization units and cost centers are aligned so each line posts to a valid dimension. Paychex holds no GL or AP documents, so ml-connector does not write financial entries back into Paychex.

Can Paychex send AP invoices or purchase orders into Deltek?

No. Paychex Flex is an HR and payroll system and has no vendor, invoice, purchase order, or GL account objects. What it provides is workers, compensation, payroll checks, and organization data, and ml-connector maps that into Deltek as employee records and labor cost journal entries rather than as AP documents.

How does the integration handle Paychex webhooks and the lack of an idempotency key?

Paychex webhooks are notification-only and carry no data, so ml-connector fetches the current worker with a GET after each event before writing it to Deltek. Because neither side offers an idempotency key, it checks for an existing employee or journal entry before posting, and it carries the Paychex page ETag forward so offset pagination does not skip or duplicate rows.