Architectural Features for High-Load AI Inference
Every layer of KiloLine is optimized to protect fragile, low-concurrency self-hosted GPU hardware without introducing unpredictable billing or latency bloat.
Dynamic Concurrency Serializer
When 20 users generate pictures simultaneously, standard web servers spawn 20 concurrent Python worker threads, causing PyTorch to allocate beyond available physical VRAM. KiloLine serializes incoming requests into an orderly queue, releasing exactly N active tasks at a time to match your exact GPU capacity.
- Zero CUDA OOM crashes under high-spike spikes
- Configurable per-endpoint slot allocation (e.g. ComfyUI: 1, TTS: 4)
- Configurable timeout & max-queue backpressure limits
max_concurrency: 2
max_queue_depth: 500
queue_timeout_sec: 120
drop_policy: "reject_with_429"
strategy: "fifo_fair_lease"
SSE Stream Keep-Alive & Async Webhooks
Standard HTTP proxies terminate connections after 30 to 60 seconds of silence. KiloLine bridges client and server over persistent Server-Sent Events (SSE). While your GPU instance runs heavy denoising steps, the gateway delivers periodic heartbeats and queue position updates directly to your frontend.
- Stream real-time progress percentages and queue wait estimates
- Asynchronous Webhook mode for jobs taking > 60 seconds
- Automated client reconnection and replay buffer
event: queue_status
data: {"position": 2, "est_wait_sec": 4.2}
event: step_progress
data: {"step": 18, "total": 25, "pct": 72}
event: output_ready
data: {"status": "completed", "duration_sec": 5.4}
Automated Spot Failover & Healthcheck Mesh
Vast.ai and RunPod spot machines can be outbid and reclaimed at any moment. KiloLine performs periodic out-of-band healthchecks. When a machine goes unresponsive or returns consecutive 5xx codes, KiloLine instantly marks it unhealthy and routes in-flight queue items to your standby backup node.
- Zero-downtime host switching without frontend redeployments
- Active circuit-breaking prevents thundering herd on rebooted GPUs
- Instant Telegram / Discord webhook notifications when hosts fail
✓ [Node-Primary] Vast.ai #8410: 200 OK (8ms)
✗ [Node-Primary] Socket Hangup (Spot interrupted)
⚡ [Circuit Breaker] Tripped! Rerouting queue...
✓ [Node-Standby] RunPod-B2 Active: Queue resumed
How KiloLine Compares to Common Alternatives
| Capability | KiloLine + Vast.ai | Self-Hosted Celery + Redis | Replicate / Modal Serverless | Cloudflare AI Gateway |
|---|---|---|---|---|
| Setup Time | < 60 seconds (URL change) | 2 - 5 days setup | Hours (Containerization) | Minutes |
| GPU Cost Profile | Flat & Ultra-cheap ($0.3/hr) | Flat (Plus VPS / Redis cost) | Linear pay-per-sec ($$$) | N/A (Proxies 3rd party APIs) |
| Concurrency Serialization | Native Edge Serializer | Requires custom worker code | Managed per-container | No GPU Queuing |
| Cold Start Duration | 0s (Always Warm Instance) | 0s (Warm) | 20s - 60s cold boots | N/A |
| Spot Instance Failover | Automatic Circuit Breaker | Manual recovery | Handled by platform | Basic retry only |
| SSE Streaming & Webhooks | Built-in Heartbeats | Complex websocket setup | Platform Polling | Pass-through only |