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# Senior Backend Engineer

- **Company:** Connexis Group
- **Location:** Greater London, UK
- **Experience:** Expert
- **Contract:** Permanent contract
- **Skills:** Python (Programming Language), MongoDB, Salesforce.Com, Indexer, Backend, Fastapi, Hubspot
- **Published:** September 8, 2026
- **Apply:** https://www.collegerecruiter.com/job/2840625016-senior-backend-engineer

## About the Role

* 6+ years building production Python services - async/await fluent
 * Deep MongoDB experience including indexing, aggregation, transactions
 * Have built billing or payments infra you're proud of
 * Care about correctness - money flows through this code, * Own ping-tree v2 (multi-buyer parallel routing)
 * Lead the CRM connector platform (HubSpot/Salesforce/Pipedrive)
 * Set the engineering bar for the next 5 hires

## Description

Own the routing engine, billing infrastructure and webhook delivery. Python/FastAPI/MongoDB. We process every inbound lead through code you write - sub-100ms p99 latency, idempotent everything, audit-trail everything.


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