Deltek and Airbase integration

What moves between them

The main flow runs from Airbase into Deltek. As bills are approved and reimbursements and card transactions are coded in Airbase, ml-connector reads them and posts them into Deltek Vantagepoint as AP invoices and journal entries, mapped to the matching Deltek GL accounts, projects, and organizations. Vendor records move the same direction so a vendor onboarded in Airbase appears as a firm in Deltek. Reference data flows back: Deltek firms, projects, and accounting codes are sent to Airbase so its spend stays coded to accounts that exist in the ledger. GL accounts are read-only in Airbase, so ml-connector never tries to write the chart of accounts into the spend platform. Cadence is scheduled polling, with Airbase webhooks used as a trigger where they are configured.

How ml-connector handles it

ml-connector stores both credential sets encrypted, obtains a Deltek bearer token through the OAuth password grant and refreshes it before the one-hour expiry, and sends the static Airbase Bearer token on every spend-API call. On the Deltek side it accepts the full tenant URL and database name per customer, since Vantagepoint publishes no shared base address, and it expects the API user role to have full field visibility so amounts and fee fields do not silently return zero. Because Vantagepoint has no idempotency key, it queries by invoice number before posting an AP invoice and uses that check to avoid duplicate vouchers. It reads Airbase approval and payment status fields, or listens for the approval webhook, so only approved spend posts and a draft never lands in the ledger. Vendors, projects, and accounting codes are mapped first so every posted line references a GL account and project that already exist in Deltek, and any configured AP approval workflow in Vantagepoint is respected so posted invoices follow the customer's approval path. Because neither side documents a rate limit, ml-connector applies conservative backoff with jitter and retries, and it tracks the manually rotated Airbase token and the one-time Deltek secret so an expired credential surfaces as an alert rather than silent failures. 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 project accounting, billing, and AP, and rolled out Airbase to give project teams corporate cards, expense reimbursement, and a bill-approval workflow. Before the integration, the accounting team exported approved bills and card-spend summaries from Airbase each week and re-keyed them into Deltek, coding each line to a project by hand, then reconciled vendor lists because a vendor added in one system was missing in the other. With Deltek and Airbase connected, approved bills, reimbursements, and card transactions post into Deltek automatically as AP invoices and journal entries against the right GL accounts and projects, vendors stay aligned, and Deltek projects and accounting codes flow to Airbase so coding is correct at the point of entry. The weekly re-keying step is gone and month-end project cost reconciliation starts clean.

What you can do

• •Post approved Airbase bills, reimbursements, and card spend into Deltek as AP invoices and journal entries, coded to the correct GL accounts and projects.
• •Keep vendor master data aligned so a vendor onboarded in Airbase appears as a firm in Deltek.
• •Send Deltek firms, projects, and accounting codes to Airbase so every transaction is coded to a real account and project.
• •Bridge the Deltek OAuth password-grant token with the long-lived Airbase portal token, refreshing each before it expires.
• •Gate posting on Airbase approval status, with retries and a full audit trail on every record.

Questions

Which direction does data move between Deltek and Airbase?

The main flow is Airbase into Deltek. Approved bills, reimbursements, card transactions, and vendor records move from Airbase into Deltek as AP invoices and journal entries, while Deltek firms, projects, and accounting codes flow back to Airbase. GL accounts are read-only on the Airbase side, so ml-connector never writes the chart of accounts into the spend platform.

How does the integration bridge the two different auth models?

Deltek Vantagepoint uses an OAuth 2.0 password grant against a tenant-specific deltekfirst.com URL, which must have password grant enabled in settings, while Airbase uses a single static Bearer token generated in its portal. ml-connector stores both encrypted, refreshes the Deltek token before its one-hour expiry, and sends the Airbase token on every call. Because Airbase has no public token-refresh flow, ml-connector tracks the manually rotated token and raises an alert before it expires.

How are duplicate AP invoices avoided when posting into Deltek?

Vantagepoint has no native idempotency key, so ml-connector queries Deltek by invoice number before creating an AP invoice and uses that check so a re-run updates rather than duplicates. It also gates posting on Airbase approval status, so an unapproved or draft bill never reaches the ledger. Any failed downstream call is retried and can be replayed from the audit trail.