From December 10, 2025 to February 28, 2026. Eighty days. Eighty-six development sessions. One CEO, one AI CTO, zero human engineers. What started as a single Python file became a payment orchestration platform with 53+ providers, 90+ API endpoints, 8 SDKs, and coverage across 200+ countries.
This article maps the complete timeline -- every phase, every milestone, every turning point. It is the bird's-eye view of how 0fee.dev was built.
Phase 1: Foundation (Sessions 001-004) -- December 10-11, 2025
The first four sessions established the entire foundation in just two days.
| Session | Date | Duration | Key Deliverables |
|---|---|---|---|
| 001 | Dec 10 | ~45 min | Backend: 42 files, 7,900 lines. FastAPI, SQLite, provider adapters, routing engine, middleware stack, encryption service |
| 002 | Dec 11 | ~60 min | Dashboard (SolidJS), TypeScript + Python SDKs, checkout widget, Celery worker |
| 003 | Dec 11 | ~60 min | Marketing website, Go/Ruby/PHP/Java/C# SDKs, Docker configuration, webhook system |
| 004 | Dec 11 | ~60 min | CLI tool, hosted checkout pages, API documentation site |
By the end of Session 004 (day 2), 0fee.dev had a complete backend, frontend dashboard, marketing site, 7 SDKs, a CLI tool, Docker setup, and API documentation. The speed was possible because Claude generated entire file trees in single responses, and Thales provided immediate architectural feedback.
Milestone: Complete full-stack prototype with 7 SDK packages.
Phase 2: Features (Sessions 005-030) -- December 12-17, 2025
The feature phase was intense. Thirteen sessions happened on a single day (December 12). The platform went from prototype to feature-rich in less than a week.
Week 1: December 10-16
| Sessions | Focus Area | Key Deliverables |
|---|---|---|
| 005 | OAuth + Dashboard | Google/GitHub/Microsoft/Apple authentication |
| 006-007 | Architecture | Merged website into SolidJS dashboard, localhost fixes |
| 008-009 | Integration | Architecture merge, full frontend unification |
| 010 | Unified Format | PAYIN_ORANGE_CI format, provider routing |
| 011 | Hosted Pages | Checkout page hosting and redirect flow |
| 012 | Analytics | Dashboard analytics, daily/weekly/monthly stats |
| 013 | Pricing | Initial 3-tier pricing model |
| 014 | UI | Modern UI redesign, Stripe-inspired layout |
| 015 | Simplification | Removed tiers, single 0.99% fee |
| 016 | Billing | Billing suspension system |
| 017 | Currencies | Worldwide currency support, formatAmount bug |
| 018 | HTTP | Migrated from requests to httpx |
| 019 | Docs | Full API documentation, 90+ endpoints |
Week 2: December 17-23
| Sessions | Focus Area | Key Deliverables |
|---|---|---|
| 020 | Admin | Admin panel MVP, UUID routes, role hierarchy |
| 021-022 | Routing | Provider priorities, routing improvements |
| 023 | Stripe | Stripe integration overhaul, middleman callback |
| 024 | Payment Links | Shareable payment URLs |
| 025-026 | Checkout | Widget improvements, embed code generator |
| 027-028 | Wallet | Add funds flow, wallet system |
| 029-030 | Onboarding | GetStarted stepper, OAuth fixes, billing integration |
Milestone: Complete feature set including admin, billing, wallet, and onboarding.
Phase 3: Polish (Sessions 031-060) -- December 24, 2025 - January 20, 2026
The polish phase focused on fixing bugs, improving UX, and making the platform production-worthy.
| Sessions | Focus Area | Key Deliverables |
|---|---|---|
| 031-032 | Currency | Big currency update: source/destination fields |
| 033-034 | Testing | Test provider, sandbox system |
| 035-036 | Feedback | Feature request module (4 tables, 20 routes) |
| 037-038 | Admin | SQLAdmin migration, column_filters fix |
| 039-040 | Stability | GetStarted fixes, Redis timeouts, webhook fixes |
| 041-042 | DevEx | API playground, interactive testing |
| 043-044 | Pricing | Coupon system, promotional codes |
| 045 | Simplification | Simplified 3-field API (amount, currency, reference) |
| 046-050 | Invoice | Invoice system, PDF generation, WeasyPrint |
| 051-054 | Compliance | Premium UI, OHADA compliance, security audit |
| 055-060 | Database | WAL fixes, provider registry bugs, amount display bugs |
Milestone: OHADA-compliant financial records, security audit complete.
Phase 4: Scale (Sessions 061-086) -- January 21 - February 28, 2026
The final phase prepared 0fee.dev for production: PostgreSQL migration, Docker deployment, internationalization, dark mode, and SDK updates.
| Sessions | Focus Area | Key Deliverables |
|---|---|---|
| 061-063 | Fixes | Amount precision, Stripe deep integration |
| 064-067 | i18n + SDKs | 15 backend + 5 frontend languages, Node.js/Python SDK rewrite, PDF receipts |
| 068-073 | UI + Stability | Premium styling, dark mode foundation, WAL checkpointing |
| 074-076 | Developer Console | Tabs, status checker, widget preview |
| 077-078 | Frontend | Infinite recursion fix, dark mode across 19 pages |
| 079-080 | SDKs v3 | PHP, Go, Rust, Java, Flutter, React Native SDKs |
| 081 | PostgreSQL | Complete migration: 39 models, 1,204 rows |
| 082-083 | i18n | Frontend internationalization, language switcher |
| 084 | Plugins | WHMCS, WordPress, WooCommerce plugins |
| 085-086 | Production | Docker deployment, EasyPanel, v1.53-1.55 releases |
Milestone: Production deployment on EasyPanel with PostgreSQL.
Session Count by Week
Week 1 (Dec 10-16): 19 sessions ████████████████████
Week 2 (Dec 17-23): 11 sessions ███████████
Week 3 (Dec 24-30): 8 sessions ████████
Week 4 (Dec 31-Jan 6): 6 sessions ██████
Week 5 (Jan 7-13): 5 sessions █████
Week 6 (Jan 14-20): 7 sessions ███████
Week 7 (Jan 21-27): 6 sessions ██████
Week 8 (Jan 28-Feb 3): 5 sessions █████
Week 9 (Feb 4-10): 5 sessions █████
Week 10 (Feb 11-17): 5 sessions █████
Week 11 (Feb 18-24): 5 sessions █████
Week 12 (Feb 25-28): 4 sessions ████The first two weeks were by far the most productive, accounting for 30 out of 86 sessions (35%). This front-loading was deliberate: build as much as possible while the architecture is fresh and simple, then shift to polish and scale.
Key Milestone Sessions
Certain sessions were inflection points that changed the trajectory of the entire project:
Session 001: The Genesis (Dec 10)
42 files, 7,900 lines, ~45 minutes. The entire backend architecture was established: FastAPI, SQLAlchemy, provider adapters, routing engine, middleware, encryption. This session set the architectural patterns that every subsequent session built upon.
Session 010: Unified Payment Format (Dec 12)
The PAYIN_ORANGE_CI format standardized how payment methods are identified across providers. Before this session, each provider used its own naming. After this session, one string (PAYIN_ORANGE_CI) uniquely identified a payment method across the entire system.
Session 013/015: Pricing Evolution (Dec 12)
Session 013 introduced a 3-tier pricing model. Session 015, the same day, ripped it out entirely and replaced it with a flat 0.99% fee. This was one of the most significant business decisions in the platform's history, and it happened within hours.
Session 020: Admin Panel (Dec 15)
The first admin panel gave Thales visibility into the platform's internals. Before this, debugging required SQL queries against the database. After this, every user, app, and transaction was visible through a web interface.
Session 045: Simplified API (Dec 20)
The API was reduced to three required fields: amount, currency, reference. This simplification removed barriers to adoption and aligned with the platform's philosophy of making payments as easy as possible.
Session 064: i18n (Dec 25)
Built on Christmas Day. 15 backend languages and 5 frontend languages. The internationalization infrastructure made 0fee.dev accessible to developers worldwide, not just English speakers.
Session 081: PostgreSQL Migration (Feb 10)
39 ORM models, 1,204 rows, complete elimination of SQLite race conditions. This was the single most important infrastructure change -- it made the platform production-ready.
Session 086: Production Deployment (Feb 28)
Docker containers, EasyPanel configuration, subdomain routing, nginx security headers. The platform went from development to production.
What the Timeline Reveals
Burst development works for AI-assisted building. The 13-session December 12 marathon would be impossible with a human engineering team (meetings, code reviews, context switching). With an AI CTO, the constraint is the CEO's endurance and decision-making speed, not the engineering throughput.
Simplification sessions are more valuable than feature sessions. Sessions 015 (removing tiers) and 045 (3-field API) had more impact on the product than any individual feature session. Knowing what to remove is harder than knowing what to add.
The bug-fixing phase is proportional to the building phase. Sessions 31-60 were primarily about fixing bugs introduced in sessions 1-30. This is normal for any software project, but the ratio (roughly 1:1) suggests that faster initial building does not eliminate the need for careful debugging.
Production readiness takes as long as feature development. Sessions 61-86 (scale phase) took approximately the same time as sessions 5-30 (feature phase). Docker, i18n, dark mode, SDK updates, and PostgreSQL migration are not glamorous work, but they account for half the total effort.
The 86 sessions tell a story of relentless execution. Two days for a prototype. Two weeks for a feature-complete platform. Two months for production-ready deployment. That is the timeline when a CEO and an AI CTO build without the overhead of human engineering teams, meetings, sprint planning, or code reviews.
This article is part of the "How We Built 0fee.dev" series. 0fee.dev is a payment orchestrator covering 53+ providers across 200+ countries, built by Juste A. GNIMAVO and Claude from Abidjan with zero human engineers. Follow the series for the complete build story.