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LiteLLM vs Not Diamond
Between an application and its model providers sit two different kinds of tool, a gateway and a router. LiteLLM is the gateway: an open-source proxy that puts 140+ providers behind one OpenAI-compatible API and tracks spend by key, user, and team. Not Diamond is the router: it picks which model should answer each request, says it is not a gateway, and is built to run beside one.
| What buyers compare | LiteLLM | Not Diamond |
|---|---|---|
| Price per monthSources 3, 4, 5 | Open-source gateway: free forever to self-host. Enterprise: quote | Pay-as-you-go: $0.05 per million tokens routed, by application. Enterprise: quote |
| Free plan or trialSources 3, 4, 5 | Open source, free forever. 30-day Enterprise trial key | Not published |
| How usage is countedSources 3, 5 | Not published | Per million tokens routed, on top of the model tokens you buy from providers |
| Integrations and featuresSources 3, 5 | One OpenAI-compatible API for 140+ providers. Virtual keys, budgets, rate limits, load balancing, lowest-cost routing, and Auto Routing to cheaper models | Model router for coding agents and long sessions. Works with an existing gateway or agent harness. Average added latency is 100 to 150 ms per request |
| Security and deploymentSources 3, 4, 5 | Self-hosted anywhere, including air-gapped, with no telemetry. Enterprise: SSO, SCIM, audit logs, SOC 2 Type 2, and ISO 27001 | SOC 2 and ISO 27001. Enterprise: SAML SSO and privacy-preserving deployment, where routing uses request metadata and never sees your payload |
| Best forSources 1, 2 | Platform and AI engineering teams that want a self-hosted LLM gateway with budgets, routing, and one API across many providers | Teams with real model spend that already run a gateway or agent harness and want per-request routing added on top |
List prices in US dollars per month before tax, as published on each vendor's site on October 29, 2026, billed monthly unless the cell says otherwise. "Quote" means the vendor sets the price through its sales team.
Which one fits
LiteLLM controls access, keys, and budgets across model providers, while Not Diamond decides which model should handle each request.
Choose LiteLLM if
- You need one OpenAI-compatible API across 140+ providers, with budgets and rate limits by key, user, team, and org.
- You want to run the gateway yourself. The MIT-licensed code self-hosts anywhere, including air-gapped, and sends no telemetry.
- You want routing inside the gateway. LiteLLM offers load balancing, lowest-cost routing, and Auto Routing that sends simple prompts to cheaper models.
Choose Not Diamond if
- Model spend is the main cost, such as coding agents or high-volume workloads. Not Diamond says teams save at least 20 to 40% with no loss in quality.
- You already run a gateway or agent harness and want routing added on top, at $0.05 per million tokens routed.
- You want routing that does not read prompts. Privacy-preserving routing decides from request metadata and locally computed features.
What buyers say
“The best option I have seen for routing is LiteLLM. Worth a look.”
phren0logy · HN, in the Ask HN “LLM Router Recommendations” · · source
“I would check out if Not Diamond (no personal affiliation) fits your use case. They had a really interesting blog post recently where they open sourced their older model router.”
LifeOverIP · HN, in the Ask HN “LLM Router Recommendations” · · source
Verdict
LiteLLM (8.0 out of 10, Recommend) is the choice when the job is governing access to many model providers, since it is open source, sets budgets and rate limits per key, team, or user, and supports air-gapped deployment. Not Diamond (7.4 out of 10, Conditional recommend) is the choice when model spend is the pain and a gateway is already in place, at $0.05 per million tokens routed and 100 to 150 ms added per request on average. Not Diamond says it plugs into an existing gateway, so the two can run together.
Methodology
We read the LiteLLM and Not Diamond product and pricing pages on October 29, 2026 and recorded every published price, limit, and plan feature. A cell reads "Not published" when the vendor does not state that detail on its site.
Scores and best-fit notes come from the AIR reviews of each product. Buyer quotes come from public forum posts that name both products.