Impact Pay is a bulk disbursement and communications platform built at DMARK Mobile for organisations that need to pay many people at once — payroll, grants, field worker stipends, and similar use cases. It combines mobile money fan-out with bulk SMS communications through a single interface.

Proprietary system — no public repository.

Two Products in One

Bulk Payments — organisations load money onto an OVA (Organisation Virtual Account) wallet. They upload a recipient list — names and mobile money numbers — and trigger disbursement. Impact Pay fans out individual mobile money transfers to each recipient via the DmarkPay telecom infrastructure, tracks delivery status per recipient, and generates settlement reports.

Bulk SMS via Blasta — the same upload-and-send model for communications. Organisations upload an audience list and compose a message. The system batches and dispatches through Blasta, DMARK's internal SMS gateway, and tracks delivery receipts.

The Engineering Problems

Fan-out at scale. Disbursing to hundreds or thousands of recipients is not a single API call. Each recipient is an individual mobile money transaction that can succeed, fail, or time out independently. Impact Pay processes these as a job queue — each transaction is tracked individually, failures are retried with backoff, and the organisation sees per-recipient status rather than a single success/fail for the entire batch.

Idempotent disbursement. If a disbursement job is interrupted — server restart, network failure, telecom timeout — it must resume without double-paying anyone already paid. Each transaction in a batch has a unique idempotency key derived from the job ID and recipient record, so replaying a batch never results in duplicate transfers.

OVA wallet integrity. The wallet balance must always reflect the true available funds. Disbursements are reserved against the wallet before the fan-out begins — the organisation cannot initiate a second batch that exceeds the remaining balance while a first batch is in flight.

SMS delivery tracking. Blasta delivers receipts asynchronously via webhook. Impact Pay correlates incoming receipts against the outbound batch and updates per-recipient delivery status, giving organisations a full view of which messages were delivered, pending, or failed.

Built With

Backend: Django, PostgreSQL
Integrations: DmarkPay mobile money, Blasta SMS gateway
Infrastructure: Docker, internal CI/CD