Hy4 preview vs Mercury Edit 2: Features, Pricing & Which Is Better (2026)
A side-by-side comparison of Hy4 preview and Mercury Edit 2 — features, pricing, and ideal use cases — to help you decide which AI tool fits your workflow.
Hy4 preview
Tencent
Tencent's open-weight Hy4 preview, a 770B-parameter Mixture-of-Experts model with 49B active parameters and a 1M-token context window.
Key features
- 770B Mixture-of-Experts Architecture: Holds 770 billion total parameters while activating only 49 billion per token, so capacity scales without proportional inference cost.
- 1M-Token Context Window: Accepts inputs exceeding one million tokens, allowing whole codebases, long document sets or extended agent traces in a single prompt.
- Apache 2.0 Open Weights: Released under a permissive licence that allows commercial use, modification and redistribution with no separate agreement.
- Productivity Task Focus: Tuned for real-world coding, office work and scientific research rather than narrow benchmark optimisation.
- Multi-Product Availability: Accessible globally through Tencent's WorkBuddy, CodeBuddy, Yuanbao and ima applications in addition to the raw weights.
- API Access via TokenHub and OpenRouter: Can be called through Tencent Cloud TokenHub or OpenRouter for teams that prefer hosted inference over self-hosting.
Best for
- Whole-Repository Code Work: Load an entire codebase into the million-token context to reason about refactors and cross-file dependencies at once.
- Long-Horizon Agent Tasks: Drive multi-step agent workflows where the full history of tool calls and intermediate results must stay in context.
- Self-Hosted Deployment: Run a frontier-scale open-weight model on private infrastructure where data cannot leave the organisation.
- Scientific Literature Analysis: Ingest large collections of papers or experimental logs and synthesise findings without chunking the input.
- Office Document Processing: Summarise, draft and restructure long reports, contracts and spreadsheets in enterprise workflows.
- Commercial Fine-Tuning: Adapt the weights for a proprietary product under the Apache 2.0 licence without negotiating a model licence.
Mercury Edit 2
Inception Labs
Diffusion-native next-edit LLM for hosted edit prediction, code editing, and high-throughput classification by Inception Labs.
Key features
- Next-Edit Prediction: Provides cursor-aware, contextual edit suggestions (single-line and multi-line) that can produce multiple coordinated edits across a file to accelerate refactoring and inline code fixes.
- Diffusion-Native Inference: Uses diffusion modeling to generate tokens in parallel, delivering higher token throughput and improved controllability compared with autoregressive edit models.
- Hosted API Access: Available as a hosted Mercury API provider (no local GPU required) with simple API key authentication (MERCURY_AI_TOKEN / INCEPTION_API_KEY) for easy integration into editors, CLIs, and server workflows.
- Multi-Edit & Cursor Prediction: Supports multi-edit operations and cursor-position-aware predictions to enable precise edits and inline integrations in code editors and IDE plugins.
- High-Throughput Classification & Structured Output: Used as a fast classifier and structured-output generator (e.g., SQL generation, routing/classification tasks) in agent and orchestration stacks.
- Editor & CLI Integrations: Integrates with tools such as cursortab.nvim and Mercury CLI, enabling direct editor workflows and autonomous code-synthesis CLIs that coordinate planning, edits, and verification.
- Scalable Integration Patterns: Designed to fit into planner→edit→verify→runtime pipelines (as seen in Mercury CLI architecture), enabling coordinated multi-step code repair and synthesis workflows.
- Hosted HTTP API for next-edit / edit-prediction requests (model IDs: "mercury-edit", "mercury-2")
- Diffusion-native generation (simultaneous token generation for high throughput)
- Multi-line and multi-edit suggestion support
- Cursor-aware prediction (cursor position contextualization)
- High throughput — community reports >1000 tokens/sec for Mercury 2 in routing use-cases
- Works with OpenAI-compatible adapters but accepts provider-specific parameters (e.g., "diffusing")
- Can be used in editor integrations (e.g., cursortab.nvim) and CLIs (e.g., Mercury CLI)
- No local GPU required for hosted usage; local inference possible via alternate providers (e.g., sweep/llama.cpp) in some projects
Best for
- Inline code editing and refactoring inside editors (Neovim, VSCode plugins) where cursor-aware, multi-line edit suggestions speed up developer edits and large-scale refactors.
- Autonomous code synthesis via CLI: drive repair and synthesis flows (Mercury CLI) that plan edits, apply multi-edit patches, and verify results as part of CI or developer workflows.
- Router/classifier in agent stacks: fast complexity classification and structured text generation (e.g., SQL or routing labels) to delegate work to other agents or tools.
- Bulk codebase modernization: run next-edit predictions across repositories to automate API migrations, style updates, and repetitive code transformations at scale.
- Cursor-aware pair-programming assistance: provide precise inline suggestions and multi-edit proposals during interactive development sessions.
- High-throughput labeling and structured output generation for pipelines that need fast, cost-effective token generation and classification.
- Inline editor code and text edit suggestions and multi-edit transformations
- Autonomous code synthesis and repair via CLI orchestration (Mercury CLI)
- Router/classifier step in multi-model pipelines to generate SQL or structured text quickly
- Batch or programmatic next-edit workflows in developer tools and plugins
- Generating structured outputs (SQL, patches) where iterative function-calling is not required