Multi-Vendor Strategy

A multi-vendor strategy is the deliberate decision to keep more than one supplier capable of serving the same need, rather than standardising on one. In AI systems this usually means being able to run a workload on more than one model provider — sometimes actively splitting traffic, sometimes simply keeping a tested alternative that could be switched to within days rather than quarters. The case for it rests on three risks that single-sourcing concentrates. Availability: an outage at a sole provider is an outage in your product. Commercial: a supplier who knows you have no alternative prices accordingly at renewal. And direction: providers deprecate models, change terms of service, alter safety behaviour, or discontinue the exact capability your feature depends on, and none of those events wait for your roadmap. The cost is real and mostly engineering. Two providers means two integrations to build and maintain, two sets of rate limits and error semantics, two behaviours to evaluate, and prompts that work acceptably on both rather than being tuned to one. Model behaviour is not portable: the same instruction produces different formatting, different refusal patterns and different failure modes across providers, so genuine multi-vendor capability requires an evaluation set run against each and maintained as both change. There is a spectrum here, and the middle is usually the right place to stand. Full active-active — live traffic split across providers — buys the most resilience and costs the most to run. A warm alternative, integrated and evaluated but not carrying traffic, provides most of the negotiating leverage and a switch measured in days. A documented plan with no working integration is the cheapest option and provides almost nothing, because the work it defers is exactly the work an incident does not leave time for. Architecture decides how expensive the option is to hold. An internal interface that separates your application from any specific provider's SDK, with the model version, the prompt and the parameters as configuration rather than code, makes switching a deployment concern instead of a rewrite. The mistake to avoid is building an abstraction so thin that provider-specific features leak through it anyway, or so thick that you cannot use anything either provider does well. Finally, decide honestly which capabilities warrant this. Not every feature needs a second supplier; a summarisation helper on an internal tool probably does not, while the model behind a customer-facing workflow with contractual commitments probably does. Applying the strategy everywhere produces a lowest-common-denominator product, and applying it nowhere produces a business whose pricing and availability are set by somebody else.