Case study
Persustain
Backend AI pipelines and deterministic emissions logic for an MVP sustainability app

- Role
- AI & Backend Engineer
- Timeline
- January 2026 – April 2026
- Team
- ISM Creative Company
- Tools
- Firebase (Cloud Functions, Firestore)TypeScriptOpenAI APIClimatiq API
Overview
Persustain is an AI-supported sustainability platform designed to help users better understand the environmental impact of their daily behaviors through explainable carbon estimation, personalized sustainability insights, and contribution-based tracking.
The project explored a central question:
How can AI systems communicate environmental impact in ways that are understandable, trustworthy, and meaningful to non-expert users?
My primary contribution focused on designing and implementing the backend AI architecture powering:
- Emissions estimation
- Activity normalization
- Sustainability insight generation
- Contribution aggregation
- Recommendation systems
Rather than using AI purely for prediction or automation, the platform treated AI as an interpretive layer, helping users understand how sustainability data is generated, what assumptions are being made, and how everyday actions connect to larger environmental outcomes.
Problem
Many green apps bury methodology or mix generative guesses with totals. The product goal was credible numbers plus readable explanations, not the other way around.
- Keep calculation paths deterministic
- Isolate AI for narrative and caveats only
- Scale cleanly as more users aggregate contributions
My role
Hands-on backend and AI implementation for the MVP.
- Cloud Functions architecture and APIs
- OpenAI and Climatiq integration
- Emissions and avoided-emissions semantics
- Firestore queries, aggregation, and cache keys
System design
Architecture split deterministic environmental math from generative interpretation: models never fabricated core emission totals.
Deterministic
- Baselines and activity math
- Aggregation and trends
- Stored totals users can trace
AI-assisted
- Explanations and summaries
- Recommendation rationales
- Assumption callouts where useful
That boundary improved reliability and made dashboards easier to reason about.
Emissions model
Early logic treated every logged action as additive emissions until we introduced avoided emissions and net framing.
- Actual CO₂
- Avoided CO₂
- Net impact
Net emissions
net_co2_kg = actual_co2_kg − avoided_co2_kg
Virtuous behaviors (e.g. biking vs driving) showed as reductions versus baseline instead of oddly positive-only totals.
Product surface
What the backend backed in the MVP:
Baseline
Onboarding-derived weekly baseline.
Activity pipeline
Normalize logs → estimates → optional LLM explanations.
Dashboard
Trends and insights from stored aggregates.
Contributions
User-scoped aggregation into program-style rollups.
Technical development
Backend stack:
- Firebase Cloud Functions (2nd Gen)
- Firestore
- TypeScript
- OpenAI API
- Climatiq API
Representative callable units:
- normalizeAndExplainActivity
- generateBaselineInsight
- generatePatternInsights
- generateEvidencePackSummary
- recommendProjectAndGoals
Multi-user aggregation exposed stale cross-user reads when caches and keys weren’t fully user-scoped. Tightened query shapes, cache keys, and refresh behavior so aggregates stayed isolated and predictable.
Outcome
The final MVP included:
- onboarding-based emissions baselines
- AI-generated sustainability insights
- activity normalization infrastructure
- contribution aggregation systems
- recommendation logic
- scalable backend AI pipelines
- user-scoped dashboard architecture
The project was later discussed in the context of future:
- verification systems
- sustainability registries
- certification workflows
- scalable contribution infrastructure
Reflection
Persustain became one of my strongest explorations of the intersection between:
- human-centered AI
- explainability
- sustainability systems
- backend architecture
- interaction design
One of the most valuable lessons from the project was recognizing that backend decisions are also UX decisions.
The structure of emissions logic, aggregation systems, and AI explanations directly influenced:
- how users interpreted environmental impact
- how trustworthy the platform felt
- how sustainability behaviors were emotionally framed
This project strengthened my interest in building AI systems that combine technical implementation with human-centered interaction design and systems thinking.