Backend
Services that behave correctly when things go wrong
Any backend works on a good day. Ours are designed for the bad ones: a timeout mid checkout, a duplicate webhook, a warehouse that stops answering, a marketing email that triples traffic in ninety seconds.
- Idempotency keys on every state changing call, so a retry can never charge or ship twice
- Explicit order state machine with every transition logged and replayable
- Circuit breakers and cached fallbacks around every external dependency
- Versioned API contracts with consumer driven contract tests in the pipeline
- Capacity proven by load test against three times the historic peak hour
Write path
Placing an order, exactly once
Order placement sequence with strong customer authentication
Figure 06 / sequenceFigure 06. Every commerce backend we build is designed around this path first. Everything else is easier than taking money correctly.
Service level objectives
The numbers we design to
These are the defaults. They are adjusted to your traffic profile during discovery and then written into the statement of work as acceptance criteria.
| Capability | Latency target, p95 | Availability | Proven by |
|---|---|---|---|
| Catalogue read | 60 ms at the API, 12 ms at the edge | 99.99% | Load test at 3x peak, synthetic checks per deploy |
| Price and promotion calculation | 90 ms | 99.99% | Load test with the real rule set, not a sample |
| Add to cart | 120 ms | 99.98% | Load test plus chaos test on the stock dependency |
| Checkout submit | 450 ms excluding the payment provider | 99.98% | Load test plus provider timeout simulation |
| Order write | 250 ms | 99.98% | Idempotency test suite, duplicate delivery test |
| Stock synchronisation | Under 60 seconds end to end | 99.9% | Reconciliation report against the ERP, run daily |
Table 04. Availability excludes planned maintenance windows agreed in advance, which we schedule outside your trading peak.
Next step
Tell us what is slowing your commerce platform down
Send the brief. A principal architect reads it, then you get a written technical assessment with options, effort and risk inside five working days. No sales call required first.