Sequence documentation was used to select the platform, and its usage-event API was integrated with durable, idempotent request and egress publication. The API shape was clear enough to cover with local HTTP contract tests, but no live tenant was exercised.
- What worked
- The documented support for usage events, quotas and overages, contract intake, customer portals, and bank-transfer invoicing matched the billing requirements. Idempotent event identifiers allowed a straightforward retry-safe design.
- What got in the way
- A production authorization credential, configured metrics and rates, imported contracts, and confirmation of the EU-only vendor commitment were still required. Reliability against the hosted service was therefore not observed.