FastContext-1.0 is a lightweight repository-exploration subagent for LLM coding agents. Instead of letting a single model both explore the repository and solve the task, FastContext separates these two roles: it is invoked on demand by a main coding agent, issues parallel read-only tool calls (READ, GLOB, GREP), and returns compact file paths and line ranges as focused context.
Specifications
| Parameters | 4B |
|---|---|
| Context window | 262,144 tokens |
| Minimum VRAM | 10 GB |
| Architecture | Qwen3ForCausalLM (vLLM) |
| License | mit |
| Modality | text->text |
| Released | June 2026 |
| Publisher | microsoft (Hugging Face) |
Pricing
| Input (per 1M tokens) | € 0.05 |
|---|---|
| Output (per 1M tokens) | € 0.10 |
Shared EU router, pay-per-token, scale-to-zero. Dedicated GPU deployments are billed hourly — see pricing.
Call it now
Drop-in replacement for OpenAI: change only the base URL and API key. The Anthropic format (/v1/messages) is supported too.
curl https://hostyourai.com/api/v1/chat/completions \
-H "Authorization: Bearer hyai-..." \
-H "Content-Type: application/json" \
-d '{
"model": "microsoft/FastContext-1.0-4B-SFT",
"messages": [{"role": "user", "content": "Hello!"}]
}'
Frequently asked questions
Can I run FastContext 1.0 4B SFT in the EU?
Yes. HostYourAI runs FastContext 1.0 4B SFT on GPUs in European datacenters via vLLM. Prompts and outputs never leave the EU and there is no US cloud provider in the chain.
Is hosting FastContext 1.0 4B SFT GDPR-compliant?
Yes. All processing happens inside the EU, a Data Processing Agreement (DPA) is available and the subprocessor list is public. Open-source weights also mean: no training on your data.
How much does FastContext 1.0 4B SFT cost?
Via the shared EU router you pay €0.05 per million input tokens and €0.10 per million output tokens, with no fixed costs. For high volume or isolation you can also run FastContext 1.0 4B SFT as a dedicated hourly GPU instance.
Is the API OpenAI-compatible?
Yes. You use the standard OpenAI SDKs with a custom base URL (https://hostyourai.com/api/v1). The Anthropic Messages API is supported as a drop-in as well.
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