Plex and Stampli integration

What moves between them

Plex invoices and purchase orders flow into Stampli on a polling schedule (typically every 15 minutes). ml-connector reads Plex invoices, POs, and GL accounts, transforms them into Stampli's CSV inbound format, and uploads them to Stampli's SFTP inbound directory. After Stampli processes invoices through its approval and matching workflows, ml-connector polls the outbound SFTP directory to retrieve approved invoices and payment files, then posts the GL impact back into Plex. GL accounts and cost dimensions are mapped in both directions so approved invoices land on valid Plex GL accounts and cost centers.

How ml-connector handles it

ml-connector stores Plex OAuth 2.0 credentials and Stampli SFTP credentials encrypted, and refreshes the Plex token when API calls return 401. It polls Plex REST API on a configurable interval using modified_date filters to detect new and changed invoices, POs, and GL accounts, then transforms the data into Stampli's CSV format with all required fields. For upload, ml-connector connects to Stampli's SFTP server using the provided credentials, creates a unique filename for each batch to prevent collisions, and uploads the CSV file to the inbound directory. On the retrieval side, it polls the outbound SFTP directory on a matching schedule, downloads approved invoice and payment files, deduplicates them using a combination of file checksums and Stampli's internal dedup, then parses the CSV output and posts GL transactions back into Plex. Plex role-based access is validated on connect, and exponential backoff with jitter is applied to handle rate limits and transient SFTP failures. Every file upload and download carries full audit metadata (filename, size, timestamp, record count) for reconciliation and replay if a downstream Plex posting fails.

A real-world example

A discrete manufacturer uses Plex ERP to manage production, procurement, and finance across two facilities, and relies on Stampli for accounts payable approval and audit trails. Before the integration, the AP team received purchase orders and invoices from Plex, manually re-entered them into Stampli for approval and matching, then after approval manually posted the GL impact back into Plex, creating a three-way reconciliation nightmare at month-end. With Plex and Stampli connected, purchase orders and incoming invoices flow directly into Stampli's approval workflow, approved invoices are automatically posted to the correct GL accounts in Plex by cost center, and the manual re-entry and reconciliation steps are eliminated. The audit trail of approvals stays in Stampli while the GL post lives in Plex, keeping both systems as sources of truth for their respective domains.

What you can do

• •Export Plex invoices, purchase orders, and GL accounts to Stampli via SFTP on a polling schedule without manual re-entry.
• •Retrieve approved invoices and payment documents from Stampli and post the GL impact back into Plex's general ledger.
• •Map Plex GL accounts and cost centers to Stampli accounting dimensions so approved invoices land on valid accounts.
• •Handle OAuth 2.0 token refresh on the Plex side and manage SFTP connections with encrypted credentials on the Stampli side.
• •Deduplicate invoice files using checksums and Stampli's built-in dedup, with full audit trails and replay capability on failed posts.

Questions

How does ml-connector move data between Plex and Stampli if Stampli has no public REST API?

Stampli does not publish a public REST API outside formal partnerships, so ml-connector uses SFTP file-based integration as the only available path. It reads Plex invoices via the Plex REST API, transforms them into Stampli's CSV inbound format, uploads them to Stampli's SFTP inbound directory, then polls the outbound directory for approved invoices and payment files to post back into Plex.

What authentication does ml-connector use for each side?

On the Plex side, ml-connector authenticates with OAuth 2.0 client credentials (Bearer token) and refreshes the token when API calls return 401. On the Stampli side, it uses SFTP credentials (hostname, port, username, password) provided by the customer, which are stored encrypted. Both credential sets are rotated and validated on connect.

How are GL accounts mapped between Plex and Stampli?

ml-connector reads the GL account master from both systems and maps them by account code and cost center in both directions. When an approved invoice flows from Stampli back into Plex, ml-connector validates that the target GL account and cost center exist in Plex before posting, preventing orphaned GL transactions.