feat: add experimental python 3.14t feature server

Author: franciscojavierarceo

.dockerignore

@@ -6,3 +6,5 @@ env
 offline_build/
 !offline_build/arrow
 !offline_build/ibis
+ui/node_modules
+sdk/python/feast/ui/node_modules

Makefile

@@ -683,6 +683,15 @@ build-feature-server-docker: ## Build Feature Server Docker image
 		-f sdk/python/feast/infra/feature_servers/multicloud/Dockerfile \
 		$(if $(filter true,$(DOCKER_PUSH)),--push,--load) sdk/python/feast/infra/feature_servers/multicloud
 
+push-feature-server-experimental-docker: ## Push experimental Python 3.14 free-threaded Feature Server Docker image
+	docker push $(REGISTRY)/feature-server:$(VERSION)-python314t-experimental
+
+build-feature-server-experimental-docker: ## Build experimental Python 3.14 free-threaded Feature Server Docker image
+	docker buildx build $(if $(DOCKER_PLATFORMS),--platform $(DOCKER_PLATFORMS),) \
+		-t $(REGISTRY)/feature-server:$(VERSION)-python314t-experimental \
+		-f sdk/python/feast/infra/feature_servers/multicloud/Dockerfile.experimental \
+		$(if $(filter true,$(DOCKER_PUSH)),--push,--load) .
+
 push-feature-transformation-server-docker: ## Push Feature Transformation Server Docker image
 	docker push $(REGISTRY)/feature-transformation-server:$(VERSION)
 
@@ -733,6 +742,11 @@ build-feature-server-dev: ## Build Feature Server Dev Docker image
 		-t feastdev/feature-server:dev \
 		-f sdk/python/feast/infra/feature_servers/multicloud/Dockerfile.dev --load .
 
+benchmark-feature-server-experimental: ## Benchmark stable vs experimental feature server containers
+	uv run python infra/scripts/benchmark_feature_server_experimental.py \
+		--baseline-image $(REGISTRY)/feature-server:$(VERSION) \
+		--experimental-image $(REGISTRY)/feature-server:$(VERSION)-python314t-experimental
+
 build-feature-server-dev-docker: ## Build Feature Server Dev Docker image
 	docker buildx build $(if $(DOCKER_PLATFORMS),--platform $(DOCKER_PLATFORMS),) \
 		-t $(REGISTRY)/feature-server:$(VERSION) \

docs/project/development-guide.md

@@ -166,6 +166,18 @@ make compile-protos-python
 docker build -t docker-whale -f ./sdk/python/feast/infra/feature_servers/multicloud/Dockerfile .
 ```
 
+### Building the experimental Python 3.14 free-threaded feature server image
+```sh
+make build-feature-server-experimental-docker
+
+# Optional: compare it to the stable image with the sample local repo
+make benchmark-feature-server-experimental
+```
+
+This experimental image is currently aimed at early compatibility and performance testing for the Python feature server. The benchmark target compares the stable and experimental containers against the sample local repo and is currently most representative for SQLite-backed serving experiments.
+
+In the current SQLite benchmark run, the experimental `3.14t` image reached `157.01 req/s` versus `187.65 req/s` for the stable image, while improving p95 latency from `274.72 ms` to `262.61 ms`. Treat that as an early data point rather than a universal result: the free-threaded stack is still evolving, and dependency behavior can outweigh any no-GIL gains on a given workload.
+
 ### Code Style and Linting
 Feast Python SDK and CLI codebase:
 - Conforms to [Black code style](https://black.readthedocs.io/en/stable/the_black_code_style/current_style.html)

docs/reference/feature-servers/python-feature-server.md

@@ -53,6 +53,32 @@ Key performance options:
 - Use HTTP health checks instead of TCP for better application-level monitoring
 - Consider horizontal pod autoscaling based on request latency metrics
 
+### Experimental Python 3.14 Free-Threaded Container
+
+Feast also ships an experimental feature-server container build for Python 3.14 free-threaded (`3.14t`) runtimes. This image is intended for benchmarking and early compatibility validation, not as the default production image.
+
+Today, the experimental image is best treated as a SQLite-oriented serving experiment. The online-serving startup path has been trimmed to avoid eagerly importing `pandas`, which makes it a better fit for free-threaded serving benchmarks, but the broader Feast runtime and some offline-oriented paths still rely on dependencies that are not fully optimized for no-GIL execution yet.
+
+```bash
+# Build the stable image
+make build-feature-server-docker
+
+# Build the experimental no-GIL image
+make build-feature-server-experimental-docker
+
+# Compare the two images against the same sample feature repo
+make benchmark-feature-server-experimental
+```
+
+The benchmark target writes a JSON report to `feature-server-experimental-benchmark.json` with throughput and latency comparisons for the stable and experimental containers. The current harness uses the sample local feature repo and is most useful for side-by-side SQLite serving comparisons. Because the free-threaded Python ecosystem is still evolving, treat the result as a workload-specific experiment and validate dependency compatibility before promoting it further.
+
+On the current SQLite benchmark run that seeded this experiment, the experimental `3.14t` image delivered lower throughput but slightly better tail latency than the stable image:
+
+- Stable image: `187.65 req/s`, `152.17 ms` mean latency, `274.72 ms` p95 latency, `35` failed requests
+- Experimental image: `157.01 req/s`, `183.21 ms` mean latency, `262.61 ms` p95 latency, `31` failed requests
+
+That works out to about `16%` lower throughput for the experimental image, alongside about `4.6%` better p95 latency on this workload. In other words, the current no-GIL image is not yet a clear performance win for SQLite online serving, but it is now easy to benchmark and iterate on as dependencies improve.
+
 ## Deploying as a service
 
 See [this](../../how-to-guides/running-feast-in-production.md#id-4.2.-deploy-feast-feature-servers-on-kubernetes) for an example on how to run Feast on Kubernetes using the Operator.
@@ -536,4 +562,4 @@ The [PyTorch NLP template](https://github.com/feast-dev/feast/tree/main/sdk/pyth
 
 ## How to configure Authentication and Authorization ?
 
-Please refer the [page](./../../../docs/getting-started/concepts/permission.md) for more details on how to configure authentication and authorization.
+Please refer the [page](./../../../docs/getting-started/concepts/permission.md) for more details on how to configure authentication and authorization.