Case study
GreenTruth / EarnDLT: A Live API Migration
EarnDLT's NestJS backend ran on GraphQL, but third-party data providers needed standard REST endpoints, on a platform already handling live regulatory data where downtime wasn't an option. We mapped the existing queries to REST, ran both in parallel, validated parity, and cut over gradually over one to two months.
Climate compliance & blockchain · EarnDLT (GreenTruth) is a blockchain-based carbon compliance platform helping companies track and report emissions under the EU's Carbon Border Adjustment Mechanism (CBAM) and Scope 3 rules.
The brief
The NestJS backend ran on GraphQL, but third-party data providers needed standard REST endpoints — on a platform already handling live regulatory data, where downtime wasn't an option.
What was built
- Mapped existing GraphQL queries and mutations to REST endpoints
- Reworked data access and request/response contracts for external providers
- Ran REST alongside GraphQL, validated parity between the two, then cut integrations over gradually rather than in one switch, over 1–2 months
The hard part
The constraint that shaped everything here: this platform reports real regulatory data, and it couldn't go down to make a backend change. That ruled out a clean-slate rewrite or a single cutover. Instead, REST and GraphQL ran side by side, every REST response was validated against what the existing GraphQL layer already produced, and integrations moved over one at a time as each was proven safe — slower than a single switch, but with no point where live reporting was at risk.
Outcome
A production REST layer that opened the platform to third-party emissions-data providers with no disruption to live CBAM and Scope 3 reporting.
Credit
Delivered by Abdullah Amir as part of the engineering team.