Evidence-led gateway comparison

Vercel AI Gateway vs OpenRouter: routing, BYOK, APIs, and where KeepRouter fits

Choose Vercel AI Gateway when the application is already built around Vercel or the AI SDK and needs team-scoped BYOK, provider ordering, model fallback, and gateway budgets. Choose OpenRouter for an independent model marketplace with a broad catalog, configurable provider routing, native client SDKs, and OpenAI-compatible access. KeepRouter is the narrower option for teams that want a focused prepaid catalog without operating provider keys. There is no universal winner: the right choice depends on who should own provider policy, credentials, billing, and application hosting. [1] [2] [6] [9]

Last reviewed 2026-08-26 · Editorial review: KeepRouter Editorial

Quick verdict

Vercel AI Gateway and OpenRouter both put several model providers behind managed API surfaces, but they start from different operating contexts. Vercel AI Gateway is part of the Vercel platform and has first-class AI SDK workflows. OpenRouter is an independent model marketplace and router with its own SDKs, OpenAI-compatible API, catalog, credits, and provider controls. KeepRouter occupies a smaller position: it sells access to a focused public catalog through KeepRouter keys and prepaid credit, without exposing self-serve upstream provider selection.

The choice is not only an SDK decision. It determines who owns provider credentials, routing policy, billing credit, fallback behavior, and incident evidence.

Side-by-side decision table

Decision factor	Vercel AI Gateway	OpenRouter	KeepRouter
Natural starting point	Vercel team or AI SDK application	Independent app that wants a broad model marketplace	App that wants a focused managed catalog and prepaid API
Client surfaces	AI SDK plus documented OpenAI and Anthropic-compatible APIs	Native client SDKs, raw REST, OpenAI SDK, and other integrations	OpenAI-compatible chat, Anthropic-compatible Messages, and model-specific documented routes
Provider routing	Automatic provider choice, order, and only rules	Provider order, only, ignore, fallback, data policy, ZDR, price, latency, and throughput controls	Private operator-managed upstream routing, not a self-serve provider policy surface
Model fallback	Models array can define model-level fallbacks	Provider fallback and router or model variants	Only the public model ID and active route are part of the customer contract
BYOK	Team-scoped provider credentials with documented system-credential fallback behavior	Provider keys with plan-dependent allowance and fees	No self-serve BYOK promise
Billing	Gateway credits or provider billing through BYOK	OpenRouter credits or provider billing through BYOK	KeepRouter prepaid USD credit
Best fit	Platform team already responsible for Vercel	Team that wants catalog breadth and request-level routing controls	Team that wants less provider-account work and can accept a smaller public contract

Routing policy is the largest product difference

Vercel documents two separate fallback layers. Provider options can let the Gateway select a serving provider automatically or follow an explicit provider order. A models array can also move to a different model when the first model fails. Those controls are useful, but every automatic change can affect response behavior, data policy, price, and the incident trail.

OpenRouter exposes a larger provider-routing surface. Current official documentation includes provider order, allow and deny lists, fallback behavior, data-collection requirements, ZDR, quantization filters, maximum price, and sorting by price, throughput, or latency. This makes the serving policy visible to the caller. It also gives the caller more policy to review, test, and own.

KeepRouter does not publish equivalent request-level provider controls. A customer selects an ID and documented endpoint from the live model catalog; upstream selection remains an operator concern. That narrower contract can reduce configuration work, but it is the wrong fit when an application must pin a particular provider, enforce ZDR at request level, or expose provider choice to its own users. The KeepRouter versus OpenRouter and KeepRouter versus Vercel AI Gateway pages document those two boundaries in detail.

BYOK changes both control and failure behavior

Vercel BYOK credentials are scoped to a team. Its documentation says a failed BYOK attempt can use Vercel system credentials, and the team needs Gateway credits for that path. A strict procurement or residency policy therefore needs an explicit test for the failure case, not only a successful BYOK request.

OpenRouter also supports BYOK, but its current allowance and charges depend on the plan and current pricing rules. Older request-count wording has appeared in parts of its documentation, while the current pricing material uses plan and list-price inference spend. Do not copy an allowance into a permanent architecture record. Capture the live rule on the review date.

KeepRouter does not offer self-serve BYOK. The customer buys KeepRouter credit and uses a KeepRouter key. This removes provider-key administration from the customer workflow, but it also means the customer cannot treat KeepRouter as a policy wrapper around its own provider contract.

API and SDK migration map

Existing integration	Move to Vercel AI Gateway	Move to OpenRouter	Move to KeepRouter
Vercel AI SDK	Change to the documented Gateway provider and model	Use the OpenRouter AI SDK integration and map provider options	Use an OpenAI-compatible or documented HTTP route; do not assume AI SDK provider options pass through
OpenAI Python or Node SDK	Change base URL, credential, and model; test supported operations	Set base URL to `https://openrouter.ai/api/v1`; map OpenRouter-specific fields	Set base URL to `https://keeprouter.com/v1`; choose a compatible live catalog ID
Raw REST	Choose one documented Gateway protocol	Call `/api/v1/chat/completions` or another documented endpoint	Call the endpoint published for the selected model
Provider-native SDK	Decide which native behavior can be represented by the chosen Gateway protocol	Replace provider-native fields or send documented OpenRouter extensions	Keep unsupported provider-native operations direct

A base URL change is only the first compile-time step. Replay streaming, tools, structured output, multimodal input, error handling, usage fields, cancellation, and the exact production model. The OpenAI-compatible migration checklist covers that test sequence.

Data controls need route-level review

OpenRouter offers documented ZDR enforcement and provider data-policy filters. Those controls apply to eligible inference endpoints, not automatically to plugins or tools. Vercel and KeepRouter have different public data contracts and routing responsibilities. Do not infer that a shared OpenAI request shape creates the same retention path.

For procurement, write the actual path as a sequence: application, gateway, selected provider or provider policy, optional tool, and storage destination. Review OpenRouter prompt retention for the OpenRouter layers and KeepRouter security for KeepRouter's published handling.

Which one should you shortlist?

Shortlist Vercel AI Gateway when Vercel deployment, AI SDK integration, team-scoped BYOK, provider order, model fallback, and Vercel budgets belong in the same operating surface.
Shortlist OpenRouter when broad model discovery, independent hosting, native OpenRouter SDKs, and request-level provider or privacy controls matter.
Shortlist KeepRouter when the goal is a smaller managed catalog, one prepaid account, published customer prices, and no customer-owned provider credentials.
Keep a direct provider integration when a provider-native operation, contract, region, or support path matters more than consolidation.

Run one bounded evaluation

Choose one model family, one endpoint, and 20 to 50 representative requests. Freeze provider policy, fallback settings, region, and retry budget. Record task success, first-token time, complete time, error type, chosen route, usage, and billed amount. Then repeat only the change you are evaluating. A broad benchmark without fixed routing cannot distinguish model behavior from gateway policy. Use the AI Gateway evaluation guide for the evidence ledger.

Frequently asked questions

Is Vercel AI Gateway better than OpenRouter?

Not universally. Vercel AI Gateway is a natural fit for Vercel and AI SDK teams; OpenRouter exposes a broader independent catalog and more request-level provider controls. Test the exact operating model you need.

Do both products support BYOK?

Yes, but the scope, allowance, fees, and fallback behavior differ. Review the current pricing and BYOK documentation and test what happens when a provider credential fails.

Can I use the OpenAI SDK with both?

Both document OpenAI-compatible access. You still need the product-specific base URL, credential, model ID, and tests for every operation your application uses.

Which has more provider-routing controls?

OpenRouter currently documents more request-level provider filters and sorting options. Vercel documents automatic selection, provider order and only rules, plus model-level fallback.

Where does KeepRouter fit?

KeepRouter fits teams that prefer a smaller managed catalog, KeepRouter credentials and prepaid billing over customer-managed provider routing or BYOK. Its public contract is intentionally narrower.

Sources reviewed

Sources last reviewed 2026-08-26