Private OpenAI-compatible vLLM endpoint serving Qwen3-4B on a GPU EC2 instance in your account. Function/tool calling and 32K context. Returns an endpoint URL and API key.
Qwen 3.5 4B Inference Endpoint deploys a private, OpenAI-compatible large language model endpoint into your own AWS account. It serves the Qwen3.5 4B model with vLLM on a single GPU EC2 instance, so your prompts and data never leave your environment.
The endpoint is OpenAI API compatible (v1/chat/completions, v1/models) and supports function/tool calling and a 32K token context window, making it a drop-in local model for IDE coding agents such as Cursor, Cline, and Continue, as well as your own apps.
The AMI is self-contained: on first boot it starts vLLM, generates an API key, and serves on port 8000. First boot downloads the model (about 18 to 25 minutes). You pay only for the EC2 GPU instance while it runs; terminate the instance to stop all charges.
Highlights
Private OpenAI-compatible Qwen3.5 4B endpoint that runs entirely in your own AWS account - prompts and data never leave your environment.
Function/tool calling and 32K token context out of the box - works as a local model for IDE agents like Cursor, Cline, and Continue.
Self-contained AMI: boots vLLM automatically, generates an API key, and serves on port 8000. Pay only for the EC2 GPU while it runs.
AWS Marketplace now accepts line of credit payments through the PNC Vendor Finance program. This program is available to select AWS customers in the US, excluding NV, NC, ND, TN, & VT.
This listing deploys the Qwen-3.5 4B inference endpoint, and the software itself is free. You pay only for the AWS GPU instance you run it on, billed by the hour. The six dimensions map to different EC2 GPU instance types across two families, each in an xlarge and 2xlarge size. The 2xlarge sizes give more compute per hour than their matching xlarge counterparts. Choose the instance type that fits your throughput and memory needs. Because billing is hourly, your cost scales with how long each instance stays running.
Top-of-mind questions for buyers
What specs do these GPU instance types give me for running the endpoint?
Each dimension maps to an EC2 GPU instance. The model targets a GPU with 24GB of memory. The xlarge sizes give a smaller core count, while the 2xlarge sizes give more vCPUs and system memory per hour. Pick the size that fits your throughput and memory needs.
Am I charged when the instance is stopped or idle?
The software itself is free, so no software charge applies. Hourly billing on this listing meters running instance time only. A stopped instance stops accruing hourly compute charges. Underlying AWS storage for a stopped instance may still bill separately through AWS.
Does running a 2xlarge instance mean I serve more requests than an xlarge?
The 2xlarge sizes carry more vCPUs and memory per hour than their matching xlarge counterparts. That extra compute can support more concurrent requests. Your realized throughput still depends on request size and model load. Load testing before production can measure time-to-first-token and throughput on your deployment.
www.holbox.ai
Helpful?
Vendor refund policy
This product is offered free of charge by Holbox AI. There are no software charges, and therefore nothing to refund through this listing.
You remain responsible for the AWS infrastructure costs of running it - the EC2 instance and its EBS root volume. Those are billed by AWS, not by Holbox AI, and are not refundable through this listing. Stop or terminate instances when they are idle. For questions about AWS charges, contact AWS Support or see https://aws.amazon.com/marketplace/help/
How can we make this page better?
Tell us how we can improve this page, or report an issue with this product.
Give us feedbackReport a problem with this product or seller
Legal
Vendor terms and conditions
Upon subscribing to this product, you must acknowledge and agree to the terms and conditions outlined in the vendor's End User License Agreement (EULA).
Content disclaimer
Vendors are responsible for their product descriptions and other product content. AWS does not warrant that vendors' product descriptions or other product content are accurate, complete, reliable, current, or error-free.
An AMI is a virtual image that provides the information required to launch an instance. Amazon EC2 (Elastic Compute Cloud) instances are virtual servers on which you can run your applications and workloads, offering varying combinations of CPU, memory, storage, and networking resources. You can launch as many instances from as many different AMIs as you need.
Version release notes
Initial release. Qwen-3.5 4B on vLLM. Hermes tool/function calling, 32K context, OpenAI-compatible API on port 8000
Additional details
Usage instructions
Launch the product on a recommended GPU instance (g5.xlarge or larger) in a public subnet. In the security group, allow inbound TCP 8000 from your IP or CIDR.
First boot downloads the model and starts vLLM (about 18 to 25 minutes). The service starts automatically - no SSH or extra configuration is required.
Retrieve the endpoint URL and API key without SSH:
Serial console: EC2 console > select the instance > Actions > Monitor and
troubleshoot > Get system log. Look for the "Qwen4B endpoint" banner with the
Endpoint and API key.
Optional (SSM Parameter Store): if you attach an IAM instance profile that grants
ssm:PutParameter on /qwen4b/*, the boot script also publishes the endpoint and key to /qwen4b/INSTANCE_ID/endpoint and /qwen4b/INSTANCE_ID/api_key.
Call the endpoint (model name is qwen4b):
curl http://PUBLIC_IP:8000/v1/chat/completions
-H "Authorization: Bearer YOUR_API_KEY"
-H "Content-Type: application/json"
-d '{"model":"qwen4b","messages":[{"role":"user","content":"Hello"}]}'
Tool/function calling: pass an OpenAI-style "tools" array; the endpoint returns
structured tool_calls (Hermes parser). Context window is 32768 tokens.
To stop all charges, terminate the instance (or delete the CloudFormation stack if
you launched via a template).
Support description: Support is provided via email for product installation, deployment, configuration, and troubleshooting. Assistance includes AMI startup problems, endpoint availability, and product-specific questions. Please include your AWS Region, CloudFormation stack events, and relevant logs when contacting support to help us investigate issues more efficiently.
AWS infrastructure support
AWS Support is a one-on-one, fast-response support channel that is staffed 24x7x365 with experienced and technical support engineers. The service helps customers of all sizes and technical abilities to successfully utilize the products and features provided by Amazon Web Services.
A self-hosted, production-ready Qwen 3.6 35B model, with 3 billion active parameters deployed into your AWS environment with a single click. Because everything runs entirely within your private cloud, your data stays secure, isolated, and fully under your control. Best of all, unlimited tokens.
Build reasoning, coding and agentic applications with K2 Horizon 7B FP8. Deploy on a single GPU in your AWS account, with open weights under Apache 2.0 and no software fee.
Be the first to review this product. We've partnered with PeerSpot to gather customer feedback. You can share your experience by writing or recording a review, or scheduling a call with a PeerSpot analyst.