Best Open Source API Gateway: 7 Options Compared
If you're searching for the best open source API gateway, you're likely choosing between a handful of well-known projects: Kong, Traefik, Apache APISIX, KrakenD, Tyk, Envoy Gateway, and a few others. There isn't one universal winner — the right choice depends on whether you need Kubernetes-native routing, plugin extensibility, raw throughput, or a low-maintenance setup for a small team.
This article breaks down the strongest open source options, what each one is actually good at, and the operational cost nobody mentions in the marketing pages: running a gateway yourself means you own the uptime, the upgrades, and the security patching.
What "best" actually means for an API gateway
Before comparing projects, define what you're optimizing for:
- Traffic pattern — north-south (external clients to your API) vs east-west (service-to-service inside a cluster)
- Deployment target — Kubernetes, bare VMs, or a hybrid setup
- Extensibility — do you need custom auth, request transformation, or rate limiting per consumer?
- Operational maturity — who's on call when the gateway goes down?
Open source gateways solve routing, auth, rate limiting, and observability at the infrastructure layer. They don't solve the problem of turning a personal AI subscription into a billable API with per-key usage tracking — that's a different layer of the stack, and it's why tools like SubToAPI exist alongside, not instead of, an API gateway.
The top open source API gateways
Kong Gateway
Kong is built on OpenResty (Nginx + Lua) and is probably the most widely deployed open source gateway. Its plugin ecosystem is the biggest reason teams pick it — auth, rate limiting, logging, and transformation are all plugin-based, and you can write custom plugins in Lua or Go.
Good for: teams that want a mature, battle-tested gateway with a large plugin marketplace and don't mind Postgres or Cassandra as a dependency for the control plane (or DB-less mode if you prefer declarative config).
Watch out for: the free version lacks some enterprise features (advanced RBAC, dev portal) that are gated behind Kong Konnect.
Traefik
Traefik's biggest selling point is automatic service discovery. Point it at Docker, Kubernetes, or Consul and it builds routing rules dynamically as services appear and disappear — no manual config reload.
Good for: Kubernetes and Docker-heavy environments where you want the gateway to reconfigure itself as deployments change. Excellent for smaller teams that don't want to hand-write routing rules.
Watch out for: less plugin depth than Kong for complex API-management use cases like fine-grained per-consumer quotas.
Apache APISIX
APISIX is built on Nginx + LuaJIT and is known for very low latency and a rich set of built-in plugins (including AI-specific ones like request/response transformation for LLM traffic). It uses etcd for configuration, which makes it a good fit for dynamic, high-scale environments.
Good for: teams that need high throughput and fine-grained traffic control (canary releases, A/B testing, circuit breaking) without paying for an enterprise license.
Watch out for: etcd is another moving part to operate and back up.
KrakenD
KrakenD is stateless by design — no database, no persistent state, configuration is a single JSON/YAML file (or generated via their config builder). It's built for API aggregation: combining multiple backend responses into one client-facing endpoint.
Good for: teams that want a fast, simple, horizontally-scalable gateway with minimal operational surface. Great if your main need is aggregating microservice responses.
Watch out for: fewer built-in auth/plugin options compared to Kong or APISIX; you'll write more glue code for advanced use cases.
Tyk
Tyk is a full API management platform (gateway + dashboard + developer portal) with an open source core. It supports GraphQL federation, which not many gateways on this list do natively.
Good for: teams that want a dashboard UI out of the box and might eventually need GraphQL gateway features.
Watch out for: the full management layer (dashboard, analytics) often pushes teams toward the paid tier as they scale.
Envoy Gateway
Envoy Gateway wraps the Envoy proxy — the same proxy inside Istio and many service meshes — into a simpler, Kubernetes Gateway API-compliant control plane. If you're already running Envoy-based infrastructure, this is the natural fit.
Good for: teams standardizing on the Kubernetes Gateway API spec and wanting Envoy's proven data plane without hand-rolling xDS configuration.
Watch out for: younger project than Kong or Traefik; smaller community and fewer third-party integrations so far.
A quick comparison
| Gateway | Best for | Config store | |---|---|---| | Kong | Plugin ecosystem, mixed workloads | Postgres / DB-less | | Traefik | Auto service discovery | None (dynamic) | | APISIX | High throughput, dynamic routing | etcd | | KrakenD | Stateless aggregation | Static file | | Tyk | Built-in dashboard, GraphQL | MongoDB/Redis | | Envoy Gateway | Kubernetes Gateway API | CRDs |
What open source gateways don't give you
None of these projects solve billing, per-application AI API keys, or usage metering for LLM subscriptions out of the box. If your actual problem is "I have a Claude subscription and I need my applications to call it as a proper HTTPS API with keys, streaming, and usage tracking per app," that's a narrower, product-specific need — not a general-purpose routing problem.
SubToAPI handles exactly that: generate scoped sub_live_... keys per application, hit a stable endpoint, and get streaming, tool use, and usage metadata without standing up infrastructure. Check the quickstart or pricing if that's the actual problem you're solving — it's not a replacement for Kong or Traefik, it solves a different layer entirely.
curl https://api.subtoapi.app/v1/messages \
-H "Authorization: Bearer $SUBTOAPI_KEY" \
-H "Content-Type: application/json" \
-d '{
"model": "claude-sonnet-4",
"max_tokens": 1024,
"messages": [{"role": "user", "content": "Summarize this PR."}]
}'How to actually choose
- Map your traffic pattern first. Kubernetes-native and service-to-service → Envoy Gateway or Traefik. External API with heavy plugin needs → Kong or APISIX.
- Test operational overhead before feature lists. Spin up a minimal deployment and see how much you have to babysit — config stores, upgrade cadence, community support turnaround.
- Don't over-provision. If you only need routing, TLS termination, and basic rate limiting, KrakenD's stateless simplicity beats a heavier platform.
- Separate infrastructure concerns from product concerns. A gateway routes traffic. It doesn't turn a subscription into a metered, per-team API product — that's a different tool, like SubToAPI's docs.
questions
Is Kong or Traefik better for Kubernetes? Traefik has more mature auto-discovery for Kubernetes and Docker out of the box. Kong is equally capable via its Kubernetes Ingress Controller but requires more explicit configuration and a config store.
Which open source API gateway has the lowest latency? Apache APISIX and KrakenD are generally the fastest in benchmarks, both built on lightweight, low-overhead cores (LuaJIT and Go respectively) with minimal processing per request.
Can I run an open source gateway for free in production? Yes — all the projects listed here are free to self-host under open licenses. The real cost is operational: patching, scaling the config store, and monitoring uptime yourself.