Wave Accounting and Monday.com integration

What moves between them

Wave invoices, customers, products, and transactions flow into Monday.com as items on designated boards. Each Wave invoice becomes a Monday item with columns mapping to invoice number, customer, amount, status, and date. Customer records sync as separate items with contact details and billing information. Transactions map to a ledger board. Updates to any Wave record (invoice status change, customer address update) trigger a webhook that ml-connector receives, parses, and applies to the corresponding Monday item. The sync is one-directional from Wave into Monday.

How ml-connector handles it

ml-connector stores Wave OAuth credentials and uses the refresh token flow to maintain valid access tokens without interruption. It registers webhooks against Wave's endpoints for invoice and customer events, validates incoming webhook payloads with HMAC-SHA256 verification, and maps Wave's GraphQL schema to Monday's board structure. Each Wave entity type (invoice, customer, product) maps to a Monday board and item type, with columns configured to hold the corresponding Wave fields. When a webhook arrives, ml-connector queries the updated Wave record via GraphQL, transforms it to match the Monday column structure, and applies the change to the Monday item via mutation. Monday's rate limits are observed with exponential backoff on 429 responses. Every record includes audit metadata for troubleshooting and replay.

A real-world example

A small service business uses Wave Accounting for invoicing and expense management, and Monday.com to track client projects and deliverables. Before the integration, the operations team worked from Monday but had to switch to Wave to check invoice status and amounts, often re-typing details from Wave into Monday status updates. With Wave and Monday.com connected, each invoice appears as a Monday item on the finance board automatically, tagged with the client project it relates to. Customer records sync into a contact board, and when an invoice is marked paid in Wave, that status flows into Monday within seconds. The team stays in Monday for the full project view while financial data stays current.

What you can do

• •Sync Wave invoices into Monday.com boards as items with invoice number, customer, amount, status, and date mapped to columns.
• •Keep customer records from Wave current in Monday with contact details, billing information, and sales history.
• •Push product data from Wave into Monday to populate pricing and availability columns on service or resource boards.
• •Authenticate Wave with OAuth 2.0, refresh access tokens automatically, and verify webhook signatures with HMAC-SHA256.
• •Apply Wave updates to Monday items in real-time, with retries and a full audit trail on every sync.

Questions

Which direction does data move between Wave Accounting and Monday.com?

Data flows one direction from Wave Accounting into Monday.com. Invoices, customers, products, transactions, and vendors sync from Wave and appear as items on Monday boards with fields mapped to Monday columns. Updates to those records in Wave trigger webhooks that ml-connector receives and applies to the corresponding Monday items.

Does Wave Accounting have any data that cannot be synced?

Wave does not expose bills, purchase orders, or employee and payroll data through its GraphQL API, so those records cannot be synced. Invoices in Wave are immutable - they can be created, approved, sent, or deleted but not edited after creation, so ml-connector reflects the invoice as a whole rather than individual field changes.

What happens if the OAuth token expires or the webhook signature verification fails?

ml-connector uses Wave's refresh token flow to maintain valid OAuth access tokens continuously, so authentication never lapses. Webhook payloads are verified with HMAC-SHA256 validation - any signature mismatch is rejected and logged, and ml-connector retries the request when Wave re-sends it.