Inception: Mercury 3 vs Poolside: Laguna XS 2.1: Live Promos, Pricing, Hidden Fees & Latency
Inception: Mercury 3 (inception/mercury-3) 2026 Q4 Developer Promotion & Volume Credits
Official 2026 Q4 promotion for Inception: Mercury 3: Activate ephemeral prefix caching to slash input costs by 50% (down to 0.05/1M) or route via asynchronous Batch API for 50% off standard token rates.
Poolside: Laguna XS 2.1 (poolside/laguna-xs-2.1) 2026 Q4 Developer Promotion & Volume Credits
Official 2026 Q4 promotion for Poolside: Laguna XS 2.1: Activate ephemeral prefix caching to slash input costs by 50% (down to 0.03/1M) or route via asynchronous Batch API for 50% off standard token rates.
In Etuki October 2026 FinOps telemetry comparing Inception: Mercury 3 (API ID: inception/mercury-3) vs Poolside: Laguna XS 2.1 (API ID: poolside/laguna-xs-2.1), Poolside: Laguna XS 2.1 offers lower standard input pricing at $0.06/1M tokens ($0.12/1M output), while Poolside: Laguna XS 2.1 leads in cached prefix economics at $0.03/1M tokens (50% discount). Inception: Mercury 3 achieves a 0ms faster P90 time-to-first-token latency (280ms vs 280ms).
Auto-discovered via live global telemetry registry.
Auto-discovered via live global telemetry registry.
| Specification / FinOps Dimension | Inception: Mercury 3 | Poolside: Laguna XS 2.1 | Verified Advantage |
|---|---|---|---|
| Official Vendor API ID | inception/mercury-3 | poolside/laguna-xs-2.1 | Pinned Snapshot IDs |
| Standard Input / Output (per 1M) | $0.1 / $0.35 | $0.06 / $0.12 | Poolside: Laguna XS 2.1 |
| Cache Read Price (per 1M) | $0.05/1M (50% Off) | $0.03/1M (50% Off) | Poolside: Laguna XS 2.1 |
| Context Window / Max Output | 977K In / 128K Out | 256K In / 32K Out | Inception: Mercury 3 |
| P90 First-Token / Edge Latency | 280ms | 280ms | Inception: Mercury 3 (-0ms) |
Mercury 3 is a diffusion-based language model from Inception, and the lab's most capable model to date. It is suited for agentic workflows and real-time applications where latency
Laguna XS 2.1 is the latest coding agent model in the 33B-A3B category from [Poolside](https://poolside.ai/) and a step forward from their Laguna XS.2 model (released in April 2026
Real-Time Stack Cost & Hidden-Fee Simulator (MAU / Token / Egress / GMV)
Calibrated with Reddit r/FinOps & r/devops telemetry: Includes Context Caching, Bandwidth Egress, and MoR Tax
🛰️Switch from Inception: Mercury 3 to Poolside: Laguna XS 2.1
Laguna XS 2.1 is the latest coding agent model in the 33B-A3B category from [Poolside](https://poolside.ai/) and a step forward from their Laguna XS.2 model (released in April 2026 Verified P90 latency of 280ms.