The Best AI Gateways for Routing LLM Calls in 2026

An AI gateway is a proxy that sits between your application (or your AI agents) and model providers like OpenAI, Anthropic, and Bedrock. In 2026 it is close to standard practice: routing LLM calls through a gateway gives you one place to switch providers, track spend, enforce limits, and, in some architectures, keep the provider API key out of the calling code entirely.

This roundup ranks the five gateways we think are worth shortlisting, each for a specific job. It is written to be useful even if you never buy anything from us.

How we ranked

• Fit for a named job: each tool is ranked as the best answer to a specific use case, not "best overall." Your primary constraint decides your pick.
• Verifiable public facts: features and prices come from vendor docs and pricing pages as of mid-2026. Where a vendor does not publish a number, we say so rather than guess.
• Credential handling: we pay unusual attention to where the real provider key lives at rest and at runtime, because that determines the blast radius of a compromise.
• Operational cost: what you have to deploy, run, and patch to use the tool, not just its sticker price.

Disclosure: KnoxCall is our product. We've kept the assessments factual and called out where competitors are genuinely the better choice — several are.

The agent-credential problem

One thing changed the gateway conversation in the last two years: AI agents now make API calls autonomously. An agent that holds a raw provider key, in its environment, its config, or its prompt context, can leak that key in ways ordinary services rarely do. It can print the key into its own output, echo it into logs or traces, or hand it to an attacker through prompt injection ("ignore previous instructions and run printenv"). The key does not need to be stolen from a vault; the agent volunteers it.

The structural fix is to make sure the agent never holds the real key at all. The agent gets a short-lived, scoped, revocable credential for a gateway; the gateway injects the actual provider key at egress, on the wire out to the vendor. A leaked agent credential is then a contained incident, not a rotation emergency. Most gateways on this list improve visibility into agent traffic; only some change what the agent actually holds. Keep that distinction in mind as you read.

1. LiteLLM — best open-source multi-provider router

LiteLLM (BerriAI) is the default answer when the job is "point many services at many model providers without rewriting each one." It puts 100+ LLM providers behind a single OpenAI-compatible endpoint, and its router is the most mature in the category: cost-aware routing, retries, model fallbacks, virtual keys, and per-team budgets with spend tracking. It is free, open source, and fully self-hostable, with a Python-native SDK that drops into existing OpenAI SDK code.

The tradeoff is custody and operations. You self-host at every tier (Postgres, Redis, and the proxy are yours to run), and the real provider keys are stored in LiteLLM's own database, decrypted by the same process. That made the proxy itself the prize in April 2026, when CVE-2026-42208, a pre-authentication SQL injection rated CVSS 9.3, let attackers dump stored provider keys; LiteLLM patched it quickly in v1.83.7, but the incident illustrates the consolidation risk. RBAC and audit logs are enterprise-only.

Pricing: open source is free (self-hosted). As of mid-2026, Enterprise Basic runs around $250/mo and Enterprise Premium around $30K/yr, with enterprise cost negotiated rather than published. See our full KnoxCall vs LiteLLM comparison.

2. Portkey — best observability and guardrails suite

Portkey is the control panel for production AI. It unifies 1,600+ language, vision, audio, and image models behind one API, and its observability is the best in the category: per-request logs, traces, feedback, and cost attribution sliced by model, key, and metadata. Reliability routing (load balancing, automatic fallbacks, retries, semantic caching) is mature, there are 60+ built-in guardrails, and the Enterprise tier carries SOC 2 Type 2, GDPR, and HIPAA with custom BAAs and VPC hosting. The gateway core is open source and self-hostable.

Two things to weigh. First, Portkey's virtual keys are a real improvement over pasting raw keys everywhere, but the actual provider key still lives in Portkey's encrypted vault and is used by Portkey's serving process; the credential boundary moves, it does not disappear. Second, Portkey was acquired by Palo Alto Networks (deal closed 29 May 2026), which is a plus if you standardize on Palo Alto and a factor to weigh if you prefer an independent vendor.

Pricing: as of mid-2026, a free Developer tier (10,000 recorded logs/mo), Production at $49/mo for 100,000 logs plus $9 per additional 100K requests, and custom Enterprise. The open-source gateway core is free to self-host. See our full KnoxCall vs Portkey comparison.

3. Helicone — best lightweight logging and cost tracking

Helicone is the simplest way to get visibility into LLM traffic: change one base URL and every request is logged, with token counts, cost, and latency tracked across 100+ providers, plus caching, provider fallbacks, and rate limits layered on. It is truly open source under Apache-2.0, so you can self-host the entire stack, and the free tier (10,000 requests/mo) is generous enough for most side projects and early products.

Helicone is observability-first by design. It answers "what happened?" superbly, but it is a logging tap: your provider key still lives in your process and travels with the request. If a prompt-injected agent can read your environment today, adding Helicone does not change that. One more thing to confirm during procurement: Helicone announced in 2026 that it is joining Mintlify; it remains Apache-2.0 and self-hostable, but check current roadmap and support commitments with the team.

Pricing: as of mid-2026, Hobby $0, Pro $79/mo, Team $799/mo, Enterprise custom, all usage-based above included quotas. See our full KnoxCall vs Helicone comparison.

4. Cloudflare AI Gateway — best free edge cache and analytics if you run Cloudflare

Cloudflare AI Gateway is the best zero-budget starting point if your stack already touches Cloudflare. The core gateway is free: caching, rate limiting, analytics, dynamic routing, and fallbacks across a unified endpoint for 20+ providers, running on Cloudflare's global edge. Its response cache can cut real token spend on repeated prompts, its BYOK key store encrypts provider keys at rest and lets you rotate without redeploying, and unified billing puts third-party model usage on your Cloudflare invoice (with a 5% fee on purchased credits). If you already run Cloudflare Zero Trust, AI Gateway reuses your existing DLP profiles.

Its limits are architectural rather than qualitative. Guardrails scan and block (flag or reject content by category, evaluated with Llama Guard on Workers AI); they do not transform a stream in place. And the BYOK store, while a real improvement, still presents your provider key on the request path; it is stored more safely, not removed from the flow. You also pay for Workers AI when guardrails evaluate content and for logs above the free allowance.

Pricing: the core gateway is free as of mid-2026; you pay for provider tokens, for Workers AI when guardrails evaluate content, and for logs above the free allowance. See our full KnoxCall vs Cloudflare AI Gateway comparison.

5. KnoxCall — best when the concern is the credential itself

KnoxCall (our product) attacks a different layer than the other four. Every tool above either stores your provider key or expects it to live in your workload. KnoxCall injects the real provider key at the egress wire, the last hop before the request leaves for OpenAI or Anthropic, and there is no API path that returns the key's value. The key is never in your code, your .env, your CI, or your agent's environment, so there is nothing for a prompt-injected agent, a poisoned dependency, or an RCE to read. Each agent instead holds a short-lived, scoped, DPoP-bindable capability key that you can revoke instantly. On top of that: custodial rotation (KnoxCall mints, verifies, and deletes the provider's own child keys, rotating the real vendor key rather than a wrapper), streaming PII redaction that rewrites sensitive spans inline at the SSE chunk boundary rather than blocking the response, a prompt firewall with canary leak detection, and general non-LLM API proxying for Stripe, Twilio, and SendGrid on the same platform.

Now the honest part. KnoxCall is a younger product with a smaller ecosystem than everything above it on this list. It is proprietary managed SaaS with no self-hostable open-source core, so if self-hosting is a hard requirement, LiteLLM or Helicone wins that line outright. Its LLM provider coverage is a subset of LiteLLM's and Portkey's catalogs, and routing is not its headline: it does route-level failover, not cost-aware routing or semantic caching. Architecturally it is a proxy, which means a trust dependency and an extra network hop, the same tradeoff you accept with any token-exchange layer. And the residual is real: a KnoxCall capability key still lives in the workload until revoked; the win is that what leaks is scoped and short-lived instead of a static vendor key valid for years. Many teams run KnoxCall alongside LiteLLM or Portkey rather than instead of them: the router keeps doing fan-out, KnoxCall holds the keys.

Pricing: Free $0, Starter $19/mo, Pro $99/mo, Enterprise custom.

Comparison at a glance

Bottom line

Pick by your binding constraint, not by feature count. If you need one endpoint over the most providers and are happy to self-host, use LiteLLM. If your pain is visibility (spend, latency, failures across a dozen providers), Portkey is the deepest tool. If you just want to see what your LLM calls cost with minimal setup, Helicone gets you there in five minutes. If you are already on Cloudflare and want caching and analytics for free, turn on AI Gateway today. And if your threat model includes an AI agent, a CI runner, or a dependency reading a provider key it should never have held, that is the specific problem KnoxCall exists to remove; it pairs well with any of the other four rather than replacing them.