Last checked 27 Oct 2026
GPT-6.1 Terra vs Muse Spark Open
GPT-6.1 Terra is billed by OpenAI. Muse Spark Open is billed by Together AI. A pair is two models from different providers whose higher published input rate is at most 1.5 times the lower one, and whose higher published output rate is at most 1.5 times the lower one. Closer rates are listed first. Each model is in at most 2 pairs, and the list stops at 12. The figures below are the rates stored on those two rows, the differences between them, and the cost of one sample workload. This page does not score quality.
Stored rates
GPT-6.1 Terra (OpenAI, Standard, under 272K) and Muse Spark Open (Together AI, Together serverless). Provider pages: OpenAI and Together AI.
| Field | GPT-6.1 Terra | Muse Spark Open |
|---|---|---|
| Input / 1M | $1.00 | $1.25 |
| Cached input / 1M | $0.05 | $0.15 |
| Output / 1M | $5.00 | $4.25 |
| Rate | Standard, under 272K | Together serverless |
| Context | 1.05M | 1,048,576 |
| Max output | 128k | n/a |
| Status | Active | Active |
| Modalities | text, image → text | text → text |
| Released | 26 Oct 2026 | n/a |
| Checked | 27 Oct 2026 | 27 Oct 2026 |
| Per request | $0.006 | $0.0059 |
| Per month | $180.00 | $177.00 |
Sample workload
The sample is the calculator's starting workload: 2,000 input tokens and 800 output tokens per request, 1,000 requests a day. A month in the calculator is 30 days, so that is 30,000 requests. The cost uses the stored input and output rates only. Cache hits, batch discounts, long-context surcharges, peak hours, and prices scheduled after an introductory window are not included. The rate label and the notes below name those other published rates.
GPT-6.1 Terra is $0.006 per request and $180.00 per month ($60.00 input and $120.00 output over the month). Muse Spark Open is $0.0059 per request and $177.00 per month ($75.00 input and $102.00 output over the month).
Muse Spark Open costs $3.00 less per month than GPT-6.1 Terra on this sample, using the stored rates above.
Open GPT-6.1 Terra in the calculatorOpen Muse Spark Open in the calculator
Notes from the sources
GPT-6.1 Terra
Standard, under 272K
Short-context standard rate for prompts under 272K tokens. The same pricing table lists long-context rates of $2 input, $0.10 cached input, and $7.50 output per 1M tokens. Batch and Flex are half of standard. Context window 1.05M and max output 128K are from the OpenAI API model list.
Muse Spark Open
Together serverless
Together AI serverless price for a Meta open model, confirmed on the Together pricing page ($1.25 input, $0.15 cached, $4.25 output). Context length 1,048,576 is from Together's serverless model catalog, which also lists the API id. Max output and a release date were not listed. This is not a price billed by Meta.