Particle-1 launches: DeepSeek V4.1 Flash tuned to use fewer tokens

Particle launched Particle-1 on October 28, 2026. It is a coding model post-trained on DeepSeek V4.1 Flash to solve tasks with fewer reasoning and tool-call tokens. It is available through Particle's API and in the RouterPlus catalog.

What changed

• Particle-1 is DeepSeek V4.1 Flash post-trained with reinforcement learning, using a rank-64 LoRA adapter, according to Particle.
• This first release focuses on software engineering. Particle says it plans to bring the approach to other domains in later releases.
• Particle reports about 45% fewer tokens on average. On four coding benchmarks it reports 28.4% to 52.2% fewer output tokens and 34.4% to 51.6% lower average cost per task than DeepSeek V4.1 Flash, with pass rates within the base model's confidence intervals.
• In the RouterPlus catalog the model ID is particle-ai/particle-1, with a 1,048,576-token context window, 131,072 maximum output tokens and one provider, Particle AI.

Prices on RouterPlus

Prices per million tokens, from the live RouterPlus catalog on October 31, 2026:

Particle's launch post computes its cost-per-task figures at $0.30 input, $0.006 cached input and $1.20 output per million tokens for both Particle-1 and DeepSeek V4.1 Flash.

What it means

Particle's claim is about cost per task, not price per token. Savings depend on how many tokens your own workload burns, so compare the two models on your real traffic before switching. Both are callable behind one RouterPlus key.

What to do

curl https://api.routerplus.com/v1/chat/completions \
  -H "Authorization: Bearer $ROUTERPLUS_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"model": "particle-ai/particle-1", "messages": [{"role": "user", "content": "Fix the failing test in utils.py"}]}'

Sign up at app.routerplus.com/login for an API key. Model pages: Particle-1 and DeepSeek V4.1 Flash 1017.

Sources

1. Particle: Introducing Particle-1
2. RouterPlus model catalog