The problem

Every platform I run needs account recovery. The usual route pays an SMS or WhatsApp provider for every message and hands them users' phone numbers. On one client system, Sweepercom, the reset feature was stuck waiting for a business SIM card.

What I built

• One verification service shared by all platforms, plus the Ozilane Key phone app
• The key that approves a reset is made inside the phone's secure hardware, never leaves it, and signs only after fingerprint or PIN
• Approvals need fingerprint or PIN and a number the user types from the screen
• Six-digit offline codes (standard TOTP) when the phone has no internet

In operation

Linked first to Sweepercom. Its first hardening release added backup codes, recovery that needs several people to approve, one sealed audit log across all apps, data export, and key rotation.

What it holds

Public keys, anonymous account IDs and a label for each linked phone. No passwords, personal names, phone numbers or app data. A full copy of its database cannot approve anything.

The problem

It started when the building management system (BMS) at the data center I manage became unreliable, leaving critical power equipment without dependable monitoring. The deeper problem was older: maintenance was written by hand in printed checklist books. Once a book was full it went to the store, and finding who did what on a given date became almost impossible. Staff had no record of their own work.

What I built

• Photos stamped with unit, time and inspector, plus readings for each equipment type
• Guided rounds through due units, QR scan-to-unit, and an offline upload queue
• Overdue alerts, and faults that clear themselves on the next clean inspection
• Maintenance checklists with approval, a compliance log with CSV export, team chat
• A built-in guide on every admin page explaining how that page and its settings work

In operation

Covers rectifiers, UPS units, precision air conditioners, generators, transformers, transfer switches and the battery room. Staff inspect on a schedule and managers audit compliance live. Real use shaped it: eight air conditioners share one display, so one photo covers the group, and alarms ticked during an inspection become tracked faults.

Why it outlasts the BMS

A working BMS watches the equipment and sends remote alarms. It does not record the people. Inspectors still need to document what they do every day, and PMS keeps that work searchable by date, unit and person. Even a small task becomes part of a staff member's record, and their proof of experience for career growth.

The problem

The company approached me because everything lived in Excel files that passed through one person:

• The register of tower sites under contract, and which guard was posted to each
• Guard contracts and payment details, which did not match from one month to the next
• Payroll, client invoices and contract deductions

Every monthly payment run started with untangling those mismatches. Pulling the reports needed to analyse daily operations was close to impossible. Directors could not see the numbers remotely, and a changed cell left no trace of who changed it or why.

What I built

• One register of tower sites and guard postings: a guard can only be posted to an approved site, with the signed contract attached
• HR and the accountant propose changes with a reason; directors see exactly which fields would change
• Every director except the one who raised a request must approve it, and any one of them can refuse it
• Payroll with NSSF, PAYE, WCF and SDL; invoicing under the client contract's billing rules
• Contract deductions, statutory payments with receipts, a monthly income statement and a full audit trail

In operation

Earlier months were loaded from the company's workbooks. The import itself found billing errors, such as a site billed twice, and these are now tracked until they are resolved with the client.

Privacy by design

Everyone signs in by role code, such as FIN-01. Roles pass from one staff member to the next. Pay lines are hidden from the very offices that process them.

People decide, the system flags

The app never removes a member; only the general meeting can do that. Where the constitution is silent or contradicts itself, the app records the question for members to decide. More than 30 such questions are recorded so far.

Next

A free period for the founding group, then licensing to other vyama (savings groups). The code already keeps each group's records separate. It runs on low-cost phones with no framework and no outside downloads.

The idea

People switch between a messenger, a music app and an app for the people closest to them. Aluta connects all three: chat with friends, hear the same song at the same moment, and keep a shared space for a partner or close friends.

What I built

• Full chat: images with annotation, voice notes, files, GIFs, reactions, replies and read receipts
• Listen Together rooms: a member streams a song from their own device while friends listen live, chat and react
• Music player with equalizer, plus a "listening now" status for friends
• Voice and group calls, biometric unlock and push notifications

Hardened by live use

A code audit found real gaps, and they are now closed: message channels require a verified sign-in, shared media is visible only to conversation members, and push notifications reach phones in the background.

Ozilane Turn

A self-hosted relay, in progress, that carries call audio when two phones cannot connect directly. It uses short-lived credentials, so apps never hold the relay's secret.

The problem

Local sellers have no trusted online channel built around how Tanzanians actually pay and receive goods: mobile money, Swahili and reliable local delivery.

What I built

• Vetted suppliers with branded storefronts and team sub-accounts
• In-house courier network with distance-based pricing and a one-time code at handover
• M-Pesa, mobile money and bank transfer; supplier payouts, commission ledger, wallet, loyalty and referrals
• Fast storefront pages for search engines, English and Swahili, installable as an app

Status

Over 90% of the planned features are built. The order flow runs end to end against a payment simulator. Connecting the live merchant account is the last step before launch.

Engineering

API and frontend tests run automatically on every push, and full browser journeys run before changes are merged. Staff accounts use role-based permissions with two-factor sign-in.

Tatizo

Kila jukwaa ninaloendesha linahitaji njia ya kurejesha akaunti. Njia ya kawaida inalipa mtoa huduma wa SMS au WhatsApp kwa kila ujumbe na kumpa namba za simu za watumiaji. Kwenye mfumo mmoja wa mteja, Sweepercom, huduma ya kubadilisha nenosiri ilikwama ikisubiri laini ya simu ya kibiashara.

Nilichojenga

• Huduma moja ya uthibitisho inayotumiwa na majukwaa yote, pamoja na programu ya simu ya Ozilane Key
• Ufunguo unaoidhinisha ubadilishaji hutengenezwa ndani ya maunzi salama ya simu, hautoki humo, na unasaini tu baada ya alama ya kidole au PIN
• Idhini inahitaji alama ya kidole au PIN, pamoja na namba ambayo mtumiaji anaiandika kutoka kwenye skrini
• Namba za tarakimu sita zinazofanya kazi bila mtandao (TOTP ya kawaida) simu inapokosa intaneti

Inavyofanya kazi

Imeunganishwa kwanza na Sweepercom. Toleo lake la kwanza la kuimarisha usalama liliongeza namba za akiba, urejeshaji unaohitaji idhini ya watu kadhaa, daftari moja la ukaguzi lililofungwa kwa programu zote, kuhamisha data, na kubadilisha funguo mara kwa mara.

Inachohifadhi

Funguo za umma, namba za akaunti zisizomtaja mtu na jina la kila simu iliyounganishwa. Hakuna nenosiri, majina ya watu, namba za simu wala data ya programu. Hata nakala kamili ya hifadhidata yake haiwezi kuidhinisha chochote.

Tatizo

Ilianza pale mfumo wa usimamizi wa jengo (BMS) katika kituo cha data ninachosimamia ulipoacha kuaminika, na mitambo muhimu ya umeme ikakosa ufuatiliaji wa uhakika. Tatizo la ndani zaidi lilikuwa la zamani: matengenezo yaliandikwa kwa mkono kwenye vitabu vya orodha vilivyochapishwa. Kitabu kikijaa kilipelekwa stoo, na kujua nani alifanya nini tarehe fulani kukawa karibu haiwezekani. Wafanyakazi hawakuwa na kumbukumbu ya kazi yao wenyewe.

Nilichojenga

• Picha zenye alama ya mtambo, muda na mkaguzi, pamoja na vipimo kwa kila aina ya mtambo
• Mizunguko ya ukaguzi inayoongoza kwenye mitambo inayodaiwa, kuchanganua QR kufika kwenye mtambo, na foleni ya kupakia bila mtandao
• Tahadhari za ukaguzi uliochelewa, na hitilafu zinazojifuta zenyewe ukaguzi unaofuata ukiwa safi
• Orodha za matengenezo zenye idhini, daftari la utekelezaji linalotoa CSV, na gumzo la timu
• Mwongozo ndani ya kila ukurasa wa msimamizi unaoeleza jinsi ukurasa huo na mipangilio yake vinavyofanya kazi

Inavyofanya kazi

Inashughulikia rectifier, UPS, viyoyozi maalum, jenereta, transfoma, swichi za kuhamisha umeme na chumba cha betri. Wafanyakazi hukagua kwa ratiba na wasimamizi hufuatilia utekelezaji papo hapo. Matumizi halisi ndiyo yaliyoiunda: viyoyozi vinane vinashiriki skrini moja, hivyo picha moja inatosha kwa kundi zima, na kengele zinazowekwa alama wakati wa ukaguzi zinakuwa hitilafu zinazofuatiliwa.

Kwa nini inadumu kuliko BMS

BMS inayofanya kazi huangalia mitambo na kutuma kengele kwa mbali. Haiandiki kumbukumbu za watu. Wakaguzi bado wanahitaji kuandika wanachofanya kila siku, na PMS inahifadhi kazi hiyo ikitafutika kwa tarehe, mtambo na mtu. Hata kazi ndogo inakuwa sehemu ya kumbukumbu ya mfanyakazi, na ushahidi wa uzoefu wake kwa ajili ya kukua kikazi.

Tatizo

Kampuni ilinifuata kwa sababu kila kitu kilikuwa kwenye mafaili ya Excel yaliyopita kwa mtu mmoja:

• Rejista ya minara iliyo chini ya mkataba, na mlinzi aliyepangwa katika kila mnara
• Mikataba ya walinzi na taarifa za malipo, ambazo hazikulingana mwezi hadi mwezi
• Mishahara, ankara za mteja na makato ya mkataba

Kila malipo ya mwezi yalianza kwa kutatua tofauti hizo. Kupata ripoti za kuchambua shughuli za kila siku kulikuwa karibu haiwezekani. Wakurugenzi hawakuweza kuona takwimu wakiwa mbali, na seli iliyobadilishwa haikuacha alama ya nani aliibadilisha wala kwa nini.

Nilichojenga

• Rejista moja ya minara na upangaji wa walinzi: mlinzi anaweza kupangwa tu kwenye mnara ulioidhinishwa, na mkataba uliosainiwa umeambatishwa
• Rasilimali watu na mhasibu wanapendekeza mabadiliko pamoja na sababu; wakurugenzi wanaona hasa sehemu zipi zitabadilika
• Kila mkurugenzi isipokuwa aliyeleta ombi lazima aliidhinishe, na yeyote kati yao anaweza kulikataa
• Mishahara pamoja na NSSF, PAYE, WCF na SDL; ankara kwa kufuata kanuni za malipo za mkataba wa mteja
• Makato ya mkataba, malipo ya kisheria pamoja na stakabadhi, taarifa ya mapato ya kila mwezi na kumbukumbu kamili za ukaguzi

Inavyofanya kazi

Miezi ya nyuma iliingizwa kutoka kwenye mafaili ya kampuni. Uingizaji wenyewe uligundua makosa ya ankara, kama mnara uliotozwa mara mbili, na sasa yanafuatiliwa mpaka yatatuliwe na mteja.

Faragha tangu mwanzo

Kila mtu anaingia kwa namba ya cheo, kama FIN-01. Vyeo vinahama kutoka kwa mfanyakazi mmoja kwenda mwingine. Mistari ya mishahara imefichwa hata kwa ofisi zinazoishughulikia.

Watu wanaamua, mfumo unaashiria

Programu haimwondoi mwanachama; ni mkutano mkuu pekee unaoweza kufanya hivyo. Pale katiba iko kimya au inajipinga, programu inaandika swali ili wanachama waamue. Zaidi ya maswali 30 ya aina hiyo yameandikwa hadi sasa.

Hatua inayofuata

Kipindi cha bure kwa kikundi mwanzilishi, kisha kutoa leseni kwa vyama vingine vya akiba. Msimbo tayari unatenganisha kumbukumbu za kila kikundi. Unafanya kazi kwenye simu za bei nafuu bila framework na bila kupakua chochote kutoka nje.

Wazo

Watu huhama kati ya programu ya ujumbe, programu ya muziki na programu ya watu walio karibu nao zaidi. Aluta inaviunganisha vyote vitatu: ongea na marafiki, sikilizeni wimbo mmoja kwa wakati mmoja, na tunzeni nafasi ya pamoja kwa mwenzi au marafiki wa karibu.

Nilichojenga

• Gumzo kamili: picha zenye maandishi juu yake, ujumbe wa sauti, mafaili, GIF, hisia, majibu na alama za kusomwa
• Vyumba vya Sikiliza Pamoja: mwanachama anatiririsha wimbo kutoka kifaa chake huku marafiki wakisikiliza moja kwa moja, wakiongea na kujibu
• Kicheza muziki chenye equalizer, pamoja na hali ya "anasikiliza sasa" kwa marafiki
• Simu za sauti na za kikundi, kufungua kwa alama ya kidole na arifa

Imeimarishwa na matumizi halisi

Ukaguzi wa msimbo uligundua mapungufu halisi, na sasa yamezibwa: njia za ujumbe zinahitaji kuingia kulikothibitishwa, picha na mafaili yanayoshirikiwa yanaonekana kwa wanachama wa mazungumzo tu, na arifa zinafika kwenye simu hata programu ikiwa imefungwa.

Ozilane Turn

Kipitishi kinachojiendesha chenyewe, bado kinajengwa, kinachobeba sauti ya simu pale simu mbili zinaposhindwa kuunganika moja kwa moja. Kinatumia vibali vya muda mfupi, kwa hiyo programu hazishiki siri ya kipitishi.

Tatizo

Wauzaji wa ndani hawana njia ya mtandaoni inayoaminika iliyojengwa kwa jinsi Watanzania wanavyolipa na kupokea bidhaa kweli: pesa ya simu, Kiswahili na usafirishaji wa ndani unaotegemewa.

Nilichojenga

• Wasambazaji waliohakikiwa wenye maduka yenye chapa zao na akaunti ndogo za timu
• Mtandao wa wasafirishaji wa ndani wenye bei kulingana na umbali na namba ya siri ya mara moja wakati wa kukabidhi
• M-Pesa, pesa ya simu na uhamisho wa benki; malipo kwa wasambazaji, daftari la kamisheni, pochi, zawadi za uaminifu na rufaa
• Kurasa za duka zinazofunguka haraka kwa injini za utafutaji, kwa Kiingereza na Kiswahili, zinazoweza kusakinishwa kama programu

Hali

Zaidi ya asilimia 90 ya vipengele vilivyopangwa vimejengwa. Mtiririko wa oda unafanya kazi mwanzo hadi mwisho dhidi ya kiigaji cha malipo. Kuunganisha akaunti halisi ya mfanyabiashara ndiyo hatua ya mwisho kabla ya uzinduzi.

Uhandisi

Majaribio ya API na ya sehemu ya mbele yanaendeshwa yenyewe kila mabadiliko yanaposukumwa, na safari kamili za kivinjari zinaendeshwa kabla mabadiliko hayajaunganishwa. Akaunti za wafanyakazi zina ruhusa kulingana na majukumu na kuingia kwa hatua mbili.