GLM 5.1 vs Inkling

Choose GLM 5.1 if you want…

• ✓A comparable all-rounder — they trade blows on the headline metrics.

Choose Inkling if you want…

• ✓Higher intelligence (Artificial Analysis index 46)
• ✓Lower price ($1.76 / 1M blended)
• ✓Larger context window (256K)

GLM 5.1

GLM-5.1 from Z.ai is built for one thing above all else: software engineering that runs on its own. A 754-billion parameter Mixture-of-Experts model, it tops the SWE-Bench Pro leaderboard at 58.4%, edging out both GPT-5.4 and Claude Opus 4.6 on real-world coding tasks. What sets it apart in practice is stamina — it can pursue a single engineering goal autonomously for up to eight hours, sustaining hundreds of iterations and thousands of tool calls without human intervention. Users consistently praise this long-horizon execution for agent-based workflows where other models stall. It also delivers fast responses, with a time-to-first-token of 1.33 seconds against a class median of 2.37 seconds. The honest trade-off: GLM-5.1 accepts text only, with no image input, making it a poor fit for visual debugging or UI-centric tasks. It also tends toward verbosity in practice, which can inflate token costs. For teams building autonomous coding pipelines, though, it earns its place at the top of the leaderboard.

Inkling

Inkling is Thinking Machines Lab's first open-weights model, and on just4o.chat it runs through the Vercel AI Gateway under thinkingmachines/inkling. It is a multimodal MoE with 975B total parameters and 41B active, trained to reason over text, images, and audio in a shared space rather than bolting on separate encoders. Controllable thinking effort lets you trade latency for depth, function calling supports agentic workflows, and a 256k context window on the gateway is roomy enough for long multimodal sessions. It is a base-tier model on just4o.chat, billed at 4 base requests per send before length multipliers, at $1.00 per million input and $4.05 per million output tokens (cached input $0.17). Practical caveats: no native web search on this route, and chat attachments currently emphasize image input even though the model itself understands audio. For teams that want an open, customizable multimodal foundation with ZDR-compatible gateway routing, Inkling is a strong addition.