Product Integrations Engineer (TypeScript/Node.js) - Microsoft 365, Google, DMS, CRM & Slack

We're building native integrations for a legal SaaS product and need an engineer who has shipped reliable integrations inside a multi-tenant SaaS application. This is a product engineering role, not a no-code automation project. You'll build a shared integration core for connections, tokens, import and sync, with an adapter for each provider. Integration scope Microsoft 365 first: SharePoint, OneDrive, Outlook and Sign in with Microsoft Google Drive and Gmail Legal document management systems, including iManage and NetDocuments Other document management tools, including Box and Dropbox CRM platforms and Slack, with specific providers and priorities to be agreed Tools our AI legal agent can call Our stack: Next.js 16, TypeScript/Node.js, Postgres/Drizzle, better-auth and BullMQ. What you will do: Build provider adapters behind a shared interface, following our architecture plan. Implement OAuth 2.0/OIDC connections, PKCE and admin consent. Store tokens securely and handle refresh with locking. Build imports and incremental sync using delta/cursor-based approaches. Handle deleted and moved files, throttling, retries and failed jobs. Implement write-back with conflict detection using eTags where supported. Write tests, document the implementation and work through pull requests with our engineering team. Must have: Shipped native integrations in a SaaS product with at least two different providers Strong TypeScript/Node.js and OAuth 2.0/OIDC experience Experience with background job queues and reliable data synchronization Ability to explain technical trade-offs and work within an existing codebase Relevant experience: Microsoft Graph, Google Drive API, iManage/NetDocuments APIs, multi-tenant SaaS and MCP/agent tools. Zapier, Make or MuleSoft-only experience is not sufficient for this role. We need someone who can implement the integrations directly in our product. In your proposal: 1. Two native SaaS integrations you personally shipped, the providers involved and your responsibility. 2. An example of how you handled token refresh, incremental sync, retries or write-back conflicts. 3. Your relevant Microsoft Graph, Google and document management API experience. 4. Earliest start date and weekly availability. We'll agree the first integration milestone and acceptance criteria with the selected engineer before starting work.