Mercury 3 vs Viv Fast
Viv Fast comes out ahead, 73 to 67 on our weighted score, though Mercury 3 is 18% cheaper per token.
Viv Fast is our pick
Viv Fast is the better all-round choice, scoring 73/100 against Mercury 3 (67). It leads on inputs & features. Mercury 3 wins on price. The score weighs price 50%, inputs & features 30%, context window 20%. None of the shared benchmarks cover every model here yet, so capability is left out of this verdict.
- CapabilityNot enough dataNo independent benchmark covers every model here yet
- Lowest priceMercury 3Mercury 3 $0.163 · Viv Fast $0.198 per 1M tokens (3:1 blend)
- Longest contextAbout the sameMercury 3 1,000,000 · Viv Fast 1,000,000 tokens
- Widest inputsViv FastMercury 3: Text · Viv Fast: Text, Images
- Self-hostingNo open weightsBoth are available only through APIs
| Measure | Weight | Mercury 3 | Viv Fast |
|---|---|---|---|
| Price | 50% | 84 | 80 |
| Inputs & features | 30% | 45 | 70 |
| Context window | 20% | 60 | 60 |
| Overall | 100% | 67/100 | 73/100 |
Left out because at least one model lacks the data: capability. The remaining weights were rescaled.
Every spec in one table
Highlighted cells lead their row. Dashes mean the data is not published.
| Specification |  Mercury 3Inception |  Viv FastVivgrid |
|---|---|---|
| Capability | ||
| Capabilities Index (ECI) | — | — |
| ECI rank | — | — |
| Price per million tokens | ||
| Input | $0.10 (best) | $0.13 |
| Output | $0.35 (best) | $0.40 |
| Cached input | $0.01 (best) | $0.05 |
| Blended (3:1) | $0.163 (best) | $0.198 |
| Long-context rate | Same rate | Same rate |
| Price source | Official Inception API | Official Vivgrid API |
| Limits | ||
| Context window | 1,000,000 tokens | 1,000,000 tokens |
| Max output | 131,072 tokens | 256,000 tokens (best) |
| Inputs and features | ||
| Text | Yes | Yes |
| Images | No | Yes |
| PDFs | No | No |
| Audio | No | No |
| Video | No | No |
| Reasoning | Yeslow · medium · high | Yeslow · high · max |
| Tool calling | Yes | Yes |
| Structured output | Yes | Yes |
| Availability | ||
| Weights | Proprietary | Proprietary |
| API model ID | mercury-3 | viv-fast |
| API providers | 3 (best) | 1 |
| Released | Oct 16, 2026 | Sep 21, 2026 |
| Knowledge cutoff | — | Sep 2026 |
What would a month cost?
Enter your expected volume in millions of tokens. List prices only; caching and batch discounts would lower these.
- Mercury 3$1.70
- Viv Fast$2.10
Which should you choose?
Which is better: Mercury 3 or Viv Fast?
Viv Fast is the better all-round choice, scoring 73/100 against Mercury 3 (67). It leads on inputs & features. Mercury 3 wins on price. The score weighs price 50%, inputs & features 30%, context window 20%. None of the shared benchmarks cover every model here yet, so capability is left out of this verdict.
Which is cheaper, Mercury 3 or Viv Fast?
Mercury 3 is cheaper at $0.10 input / $0.35 output per million tokens (official Inception API price). Viv Fast costs $0.13 input / $0.40 output per million tokens (official Vivgrid API price). At a typical mix of three input tokens to one output token, that is $0.163 per million tokens for Mercury 3 versus $0.198 for Viv Fast (1.2× as much).
Which scores higher on benchmarks?
There is no independent benchmark that covers both models yet. Mercury 3 has not been scored yet and Viv Fast has not been scored yet.
Which is better for coding?
There are no published SWE-bench Verified results for Mercury 3 and Viv Fast yet, so there is no like-for-like coding score. Test both on a sample of your own tasks. Both support tool calling for agent workflows.
Which has the bigger context window?
Mercury 3 and Viv Fast share the same 1,000,000-token context window. Maximum output per response: Mercury 3 up to 131,072, Viv Fast up to 256,000 tokens.
Which can read images, PDFs, audio or video?
Mercury 3 accepts text; Viv Fast accepts text and images. Viv Fast handles the widest range of inputs.
Are any of these open source?
No. Mercury 3 and Viv Fast are proprietary and only available through APIs and apps.
Which is newer?
Mercury 3 is the newest, released Oct 16, 2026. Viv Fast came out Sep 21, 2026. Knowledge cutoff: Viv Fast Sep 2026.
How do you decide the winner?
Each model gets a 0–100 score on capability (50%, independent benchmark results); price (25%, blended price per million tokens (3 input : 1 output), log scale); inputs & features (15%, image, PDF, audio and video input, tool calling, structured output and reasoning); context window (10%, maximum tokens per request, log scale). Dimensions missing for any model are dropped and the remaining weights rescaled, so every model is judged on the same evidence. Specs and prices come from public model listings and the labs’ own API pages; capability scores come from independent benchmark runs. Data updated Nov 2, 2026.
