Quick Verdict
| Need | Better first pick | Why |
|---|---|---|
| Cheapest bulk text | DeepSeek V4 Flash | Very low input, output, and cached-input rates |
| Budget escalation | DeepSeek V4 Pro | Stronger than Flash while still far below flagship OpenAI rates |
| OpenAI ecosystem | GPT-5.6 Luna or Sol | Better tooling, multimodal coverage, integrations, and procurement familiarity |
| Premium reasoning | GPT-5.6 Sol | Expensive, but the safer OpenAI escalation route |
| Narrow utility calls | Test both | Small OpenAI models can compete on input-heavy tasks |
For live model tables, use DeepSeek pricing, OpenAI pricing, and the calculator above.
Pricing Table
| Model | Input | Cached input | Output | Best fit |
|---|---|---|---|---|
| DeepSeek V4 Flash | $0.14 | $0.0028 | $0.28 | Cheapest DeepSeek default for routing, extraction, and support drafts |
| DeepSeek V4 Pro | $0.435 | $0.003625 | $0.87 | Stronger budget reasoning and coding route |
| GPT-4.1 nano | $0.10 | $0.025 | $0.40 | Legacy OpenAI utility baseline |
| GPT-5.4 mini | $0.75 | $0.075 | $4.50 | Practical OpenAI production default in older stacks |
| GPT-5.6 Luna | $1.00 | $0.10 | $6.00 | Lower-cost current GPT-5.6 route |
| GPT-5.6 Sol | $5.00 | $0.50 | $30.00 | Premium OpenAI flagship route |
DeepSeek V4 Flash is the obvious price winner against OpenAI flagship routes. V4 Pro is no longer just a curiosity; it is a realistic middle tier when Flash is not strong enough and GPT-5.6 Sol is too expensive.
Cost Scenarios
| Scenario | Token mix | Cheapest likely route | Why |
|---|---|---|---|
| Support bot | Many short chats | DeepSeek V4 Flash | Output is cheap and quality can often be checked |
| Document summaries | Heavy input, shorter output | DeepSeek V4 Flash or small OpenAI | Input-heavy work can make tiny OpenAI models competitive |
| Coding assistant | Large input and output | DeepSeek V4 Pro first, OpenAI escalation | Quality risk matters more than sticker price |
| Cached agent context | Repeated prompts and schemas | DeepSeek | Cached-input rates are unusually low |
The real comparison is cost per accepted answer. If DeepSeek needs more retries, longer prompts, or extra review, the savings shrink. If it passes evals, the savings compound quickly.
What You Give Up With DeepSeek
OpenAI still has the stronger ecosystem: SDK familiarity, third-party integrations, multimodal breadth, enterprise comfort, and premium model depth. DeepSeek is strongest when the task is text-first, quality is measurable, and cost is the constraint.
Routing Pattern
| Workload | Default route | Escalation route |
|---|---|---|
| Classification or tagging | DeepSeek V4 Flash | GPT-5.6 Luna |
| Support drafts | DeepSeek V4 Flash | DeepSeek V4 Pro or GPT-5.6 Luna |
| RAG answers | DeepSeek V4 Pro | GPT-5.6 Sol |
| Coding triage | DeepSeek V4 Flash | DeepSeek V4 Pro |
| Hard code changes | DeepSeek V4 Pro | GPT-5.6 Sol or a specialist coding model |
FAQ
Is DeepSeek still cheaper than OpenAI?
Usually, yes, especially V4 Flash versus GPT-5.6 Sol. Small OpenAI utility models can still compete in narrow input-heavy workloads.
Is DeepSeek V4 Pro cheaper than GPT-5.4 mini?
Yes on the current tracked token prices. Quality, tooling, governance, and retry rate can still make OpenAI the better production choice for some teams.
Should I replace GPT-5.6 Sol with DeepSeek?
Not blindly. Use DeepSeek to cut bulk text costs, then keep GPT-5.6 Sol or another premium model for tasks where quality risk is high.
Which model should startups test first?
Start with DeepSeek V4 Flash, DeepSeek V4 Pro, GPT-5.6 Luna, and your current OpenAI default. Route based on eval results, not provider loyalty.
Bottom Line
DeepSeek V4 Flash is one of the cheapest serious text API routes in the tracker. V4 Pro gives teams a stronger budget escalation path. OpenAI still wins when tooling, multimodal features, governance, or premium reasoning matter more than token savings.