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Kenya · UMS Kenya

Ancel Ajanga

Lead Software Engineer & Head of IT

I build and strengthen the systems people depend on — across software, infrastructure and day-to-day operations.

Currently

Lead Software Engineer & Head of IT at Utility Metering Solutions (UMS Kenya)

2026 — Present · Production systems, IT operations and durable engineering.

View experience

Also contributing part-time as an AfterQuery Expert Software Engineer.

Selected workGet in touchResume

Engineering identity

The kind of engineer I am

Derived from production ownership and the systems documented in Selected Work — not personality marketing.

  1. 01

    Production ownership

    Maintain and strengthen live systems — investigate issues, ship durable fixes and keep technology operations recoverable.

  2. 02

    Financial correctness

    Ledgers, idempotent payments, tenant isolation — systems where wrong state is expensive.

  3. 03

    Failure-aware design

    Circuit breakers, pending→settled flows, graceful degradation and explicit recovery paths.

  4. 04

    Real-time coordination

    WebSockets, optimistic UI, conflict handling and storage split for hot path vs durable truth.

  5. 05

    Policy-bound automation

    AI/ops remediation gated by signed intents and declarative policy — not blind auto-execution.

Selected work

Systems that show how I think

Prioritized by engineering significance — decisions and tradeoffs, not badge rows.

01 · Secure messaging · Real-time · Privacy

Inkly

Lead Systems Architect & Full-Stack Developer

  • WebSockets
  • PostgreSQL
  • MongoDB
  • Redis
  • Cryptography
  1. Clients ↔ WebSocket cluster
  2. Redis coordination / rooms
  3. PostgreSQL durable state
  4. MongoDB event / log store

Problem

Centralized messaging models struggle to combine zero-knowledge privacy with horizontal real-time scale.

What was built

A high-availability secure messaging architecture with cryptographic lifecycle controls and three-tier storage (PostgreSQL, MongoDB, Redis).

Decision that mattered

Separated hot path delivery from durable truth: Redis for coordination, PostgreSQL for relational integrity, MongoDB for flexible event/log shapes.

Tradeoff

Accepted storage complexity to keep privacy boundaries and delivery resilience independent under partition.

Outcome

Production-oriented architecture for low-latency real-time delivery patterns with resilient storage separation.

Architecture documented in case study; public repo not available.

02 · Infrastructure · AIOps · Policy

Aegis

Systems / Infrastructure Engineer

  • OPA
  • Agents
  • Zero-Trust
  • OpenTelemetry
  1. Control plane proposes intents
  2. OPA / signed intent gate
  3. Agents pull tasks
  4. Shadow mode before autonomy

Problem

AI-driven remediation can act faster than operators can trust — creating a gap between automation and safety.

What was built

An autonomous infrastructure guardrail system where suggestions are gated by Open Policy Agent rules and signed intents.

Decision that mattered

Pull-based agents with OPA-evaluated signed intents so the control plane can propose work but cannot push execution into a cluster.

Tradeoff

Chose pull latency (seconds) over push speed to keep inbound cluster attack surface closed and policy declarative via GitOps.

Outcome

A pull-based control plane pattern that keeps remediation policy-bound. Work in progress; architecture published in the case study.

In progress — see case study and architecture docs.

03 · Fintech · Multi-tenancy · Audit

LedgerX

Full-Stack Software Engineer

  • Next.js
  • NestJS
  • PostgreSQL
  • Prisma
  • MongoDB
  1. Next.js + NestJS
  2. PostgreSQL ledger / orgs
  3. MongoDB activity logs
  4. Payment adapters + circuit breakers

Problem

Financial operations need invoicing, payments, double-entry accounting, audit and fraud signals in one coherent system.

What was built

A multi-tenant financial platform spanning invoicing, payments, ledger correctness, compliance hooks and diagnostics.

Decision that mattered

PostgreSQL for transactional/compliance data; MongoDB for high-volume activity logs; in-process domain events for audit and diagnostics.

Tradeoff

Kept an in-process event bus instead of an external queue to reduce moving parts while documenting single-process limits.

Outcome

A production-grade platform case study covering ledger-backed workflows and multi-tenant financial operations.

04 · Fintech · Payments · Resilience

NestFi

Full-Stack Software Engineer

  • NestJS
  • PostgreSQL
  • M-Pesa
  • Redis
  1. PostgreSQL transactional ledger
  2. MongoDB audit / callback events
  3. Redis coordination locks
  4. Idempotent Daraja adapters

Problem

Mobile money and async payment flows fail in ways that corrupt wallet state when correctness is treated as optional.

What was built

A financial coordination platform with ledger-first wallets, idempotent M-Pesa integration and hybrid storage.

Decision that mattered

Balances derived from ledger entries (not mutable columns); pending→settled payment flow with Redis locks for withdrawal coordination.

Tradeoff

Chose PostgreSQL ACID for the ledger over NoSQL convenience — eventual consistency is unacceptable for money movement.

Outcome

Correctness-first payment architecture documented for high-risk, low-trust payment environments. In progress.

In progress — architecture docs available via case study links.

All case studiesFull project index

Experience

Where the work happens

Current production ownership first. Previous independent and progression context stays secondary — full detail on the experience page.

Current

  1. 2026 — Present

    Kenya

    Lead Software Engineer & Head of IT

    Utility Metering Solutions (UMS Kenya)

    Lead software engineering and IT operations for production systems that support financial and utility workflows — including systems that handle millions of KES in daily transactions. The work spans maintaining and improving live systems, shipping new capabilities, investigating production issues and bridging engineering with customer service and business operations.

    • Maintain and improve production systems involved in financial and utility workflows.
    • Engineer new software capabilities and operational improvements that reduce avoidable manual work.
    • Lead the IT function so technology operations remain available and recoverable.

  2. Part-time · Ongoing

    Remote

    Expert Software Engineer

    AfterQuery Experts

    Contribute part-time as an AfterQuery Expert Software Engineer alongside the UMS role.

Previous

  • Independent Systems Engineer & Fullstack Developer

    Independent practice

    2024 — 2026

  • Engineering progression

    Self-directed practice & earlier freelance delivery

    2021 → 2026

View full experience

How I build

Engineering depth without a case-study wall

Principles a senior engineer can scan — each tied to systems already on this site.

Data integrity first

In money and multi-tenant systems, balances and permissions are derived carefully — ledger entries and scoped queries beat mutable shortcuts.

Evidence · NestFi · LedgerX · EduManage

Isolate failure domains

Payment adapters, real-time channels and audit logs fail differently. I separate stores and paths so one outage does not corrupt the whole system.

Evidence · Inkly · OpsFlow · NestFi

Make automation earn trust

Remediation that cannot be explained will not be enabled. Shadow mode, signed intents and policy engines come before autonomy.

Evidence · Aegis

Ship with explicit tradeoffs

Pull vs push, ACID vs flexibility, in-process events vs queues — I document the constraint that forced the choice.

Evidence · Case studies

Prefer interactive experiments? Open Labs.

Engineering

Capability, grouped by how systems are built

Technologies that appear in shipped work and case studies — not every package ever imported.

Frontend

  • React
  • Next.js
  • TypeScript
  • Flutter
  • Tailwind CSS

Backend

  • NestJS
  • Node.js
  • Express
  • Django
  • REST
  • WebSockets

Data

  • PostgreSQL
  • MongoDB
  • Redis
  • Prisma

Infrastructure

  • Docker
  • Kubernetes
  • CI/CD
  • Cloudflare

Architecture

  • Multi-tenant SaaS
  • Event-driven design
  • Idempotency
  • Hybrid storage

Reliability

  • Circuit breakers
  • Graceful degradation
  • Audit trails
  • OPA policy gates

Prefer charts and project mappings? Open the full stack page.

Collaboration

How I work with teams

Open to a small number of thoughtful collaborations involving reliable software, operational systems and technically demanding product work.

Production ownership

I currently lead software and IT at UMS Kenya — maintaining live systems, shipping improvements and keeping operations recoverable.

Tradeoffs are documented

Expect explicit decisions: why this store, why this consistency model, what was deferred and what breaks first under load.

Select collaborations

Open to a small number of thoughtful collaborations around reliable software, operational systems and technically demanding product work.

Labs

Where I pressure-test ideas

Experiments framed as hypotheses and constraints — not random animations.

Policy-gated remediation

In progress

Can AI suggest infrastructure fixes without being allowed to execute unsafely?

Pull-based agents · OPA · signed intents

Learned: Shadow mode is a trust prerequisite before autonomy.

Related case study

Correctness under async payments

In progress

What happens to wallet state when M-Pesa callbacks arrive late, twice, or never?

Ledger-first balances · idempotency · Redis locks

Learned: Pending→settled beats optimistic credit for money movement.

Related case study

Privacy vs horizontal realtime

Live architecture

Can zero-knowledge messaging still scale across WebSocket clusters?

3-tier storage · cryptographic lifecycle

Learned: Separate delivery coordination from durable truth stores.

Related case study
Full labs & site experiments

Journal

Thinking in public

Selected writing on failure modes, architecture and systems that actually shipped.

All journal entries
Ancel Ajanga, Lead Software Engineer & Head of IT

About

How I approach software

I build systems the way I want to operate them later: clear boundaries, explicit failure modes and data that stays trustworthy under load and partial outage.

The work I enjoy sits at the intersection of product engineering, operations and architecture — financial and utility workflows, real-time collaboration, multi-tenant isolation and infrastructure that can be reasoned about.

Based in Kenya. Lead Software Engineer & Head of IT at UMS Kenya — building and strengthening production systems people depend on. I currently serve as Lead Software Engineer & Head of IT at Utility Metering Solutions (UMS Kenya) and contribute part-time as an AfterQuery Expert Software Engineer.

More about meEngineering philosophy

Contact

Start a conversation

Open to a small number of thoughtful collaborations involving reliable software, operational systems and technically demanding product work.

Open contact pageEmail ancel.ajanga@yahoo.com