Author: 123API Team · Published: 2026-09-15
Choosing a model is the single biggest lever on both output quality and your bill. This comparison covers the four models developers ask about most in 2026, measured the way a builder actually cares about: not benchmark leaderboards, but quality-per-dollar in real workloads.
How we compared #
We rated each model on four axes that matter in production: reasoning quality, speed (time-to-first-token), price (blended $/1M tokens), and context window. Numbers shift monthly, so treat the table as a starting point and verify live pricing in the API Reference.
| Model | Best at | Context | Relative speed | Relative cost |
| GPT-4o | General purpose, vision | 128K | Medium | Medium |
| Claude (Sonnet) | Long docs, coding, safety | 200K | Medium | Medium |
| Gemini | Multimodal, long context | 1M+ | Fast | Low–Medium |
| DeepSeek | Reasoning, low cost | 128K | Fast | Low |
Pick by use case #
- Open-ended chat & vision: GPT-4o.
- Long documents & agents: Claude.
- Huge context or multimodal: Gemini.
- Reasoning on a budget: DeepSeek.
How to choose on 123API #
123API exposes all four through one key, so you are never locked in. Use the model catalog to filter by capability, then route by cost with the cost optimization guide. New to the platform? Start with the quickstart guide.
FAQ
Which model is cheapest? DeepSeek and Gemini are typically the lowest cost; route easy tasks to them. Can I switch later? Yes — change the model field; the endpoint stays the same.
Suggested internal links (positions)
- In “verify live pricing” sentence → API Reference (anchor: “API Reference”).
- “use the [model catalog]” → model catalog (anchor: “model catalog”).
- “route by cost with the [cost optimization guide]” → cost optimization guide (anchor: “cost optimization guide”).
- “Start with the [quickstart guide]” → quickstart guide (anchor: “quickstart guide”).
