Not Diamond vs OpenRouter
Both are llm gateways tools. Here is how they actually differ on price, billing model and deployment.
Not Diamond
A model router that recommends rather than proxies - it tells your gateway which model to call and gets out of the way. That architecture means no request-path dependency, which nothing else in this category offers.
OpenRouter
A managed gateway to 500+ models with no subscription, charging 5.5% on top of provider prices. Two details to know - there are no volume discounts, and your credits expire after a year of non-use.
| Not Diamond | OpenRouter | |
|---|---|---|
| Category | LLM Gateways | LLM Gateways |
| Our rating | 4/5 | 4/5 |
| Starting price | Conflicting reports | 5.5% markup |
| Billing meter | No usage metering | markup-pct |
| Free plan | Yes | Yes |
| Free self-hosting | No or paid tier only | No or paid tier only |
| Best for | Teams already running a gateway who want smarter per-request model selection without putting another vendor in the request path, particularly for coding agents where model spend is high and uncontrolled. | Small teams and prototypes trying many models without wanting infrastructure, and anyone whose monthly provider spend stays below roughly $5,000 where the markup costs less than running a gateway. |
Our verdict on Not Diamond
Not Diamond is architecturally the most interesting thing in this category because it declines to be a gateway. Integrations are stack-agnostic through its API, and recommendations are executed in your own model gateway and harness - so it tells you which model to call and gets out of the way. Every other router in this category is a proxy, which means adopting it creates a request-path dependency and a new availability risk. Not Diamond has neither. It composes with LiteLLM, Vercel, Cloudflare or your own proxy rather than replacing any of them, which makes it unusually low-commitment to try. The product is a pre-trained Chat router, a Code router aimed at coding-agent cost currently in early access, and custom routers trained on your own data. That last one matters most, because the weakness of generic routing is that your workload is not the benchmark it was tuned on. The unsatisfying part is pricing, where sources directly contradict each other, and the fact that the most differentiated capability is still early access.
Full Not Diamond review →Our verdict on OpenRouter
OpenRouter is the fastest way to get access to a very large number of models, and for small teams it is close to unbeatable on convenience. One key, one OpenAI-compatible endpoint, 500+ models, no subscription, and 27 community-subsidised models that are genuinely free. If you are evaluating which model suits a problem, the ability to switch between hundreds by changing a string is worth real money in engineering time alone. The economics turn against you as you grow, and the reason is structural. The 5.5% markup carries no volume discounts, so the fee scales indefinitely with your spend while delivering nothing additional - at $50,000 a month that is $2,750 every month for the same service you got at $1,000. Two smaller details are worth knowing. Credits expire after one year of non-use, which is unusual enough to catch people out. And there is no self-hosted option, so their availability is your availability, with no fallback you control.
Full OpenRouter review →Frequently Asked Questions
What is the main difference between Not Diamond and OpenRouter?
Not Diamond: Teams already running a gateway who want smarter per-request model selection without putting another vendor in the request path, particularly for coding agents where model spend is high and uncontrolled. OpenRouter: Small teams and prototypes trying many models without wanting infrastructure, and anyone whose monthly provider spend stays below roughly $5,000 where the markup costs less than running a gateway. Both sit in LLM Gateways, so the decision usually comes down to billing model and deployment rather than raw capability.
Which is cheaper, Not Diamond or OpenRouter?
It depends entirely on your workload shape, because they meter differently - Not Diamond bills on no usage metering and OpenRouter bills on markup-pct. Published starting prices are Conflicting reports and 5.5% markup respectively, but those numbers are not comparable until you apply them to the same traffic. Use our cost calculator to model both against your own request volume and span count.
Can I self-host Not Diamond or OpenRouter?
Not Diamond: No or paid tier only. OpenRouter: No or paid tier only. Free self-hosting means no licence fee, not no cost - you still own the infrastructure, upgrades and on-call.