A flat-rate AI API is an application programming interface that lets you call large language models for a fixed monthly (or annual) fee instead of charging for every input and output token. You pay one known amount, receive an API key, and send requests — the invoice does not grow when a conversation gets longer or traffic spikes.
Daymora is a flat-rate AI API: $50/month (or $500/year) for access to GPT-5, Claude Sonnet 4, and Gemini 2.5 Pro through one REST endpoint. This article defines the model, contrasts it with token billing, and shows when each option wins.
Flat-rate AI API: a one-sentence definition
A flat-rate AI API sells model access as a subscription. Billing is independent of token count. Fair-usage policies still apply — the point is predictability, not a literal infinite meter.
That is the opposite of pay-per-token APIs (OpenAI, Anthropic, Google, and most others), where each prompt token and each generated token is an line item.
How pay-per-token billing works
Pay-per-token pricing multiplies:
- tokens in the system prompt
- tokens in retrieved context or tools
- tokens in conversation history
- tokens in the user message
- tokens in the model output
- tokens burned by retries and timeouts
A user typing 20 tokens can easily trigger a 2,000–8,000 token request in production. List prices that look like "$X per million tokens" therefore understate real cost. See The True Cost of AI APIs for the full overhead stack.
How a flat-rate AI API works
With a flat-rate provider you:
1. Subscribe at a published monthly or annual price
2. Generate an API key
3. Call a documented HTTP endpoint (for Daymora: POST /api/v1/chat)
4. Pay the same amount whether a given month is quiet or busy
There is still engineering work — auth, streaming, error handling — but cost control work (truncating history, disabling retries, shrinking context to dodge the bill) largely goes away. That is the product difference, not just the invoice.
Flat-rate vs pay-per-token at a glance
| Dimension | Pay-per-token AI API | Flat-rate AI API |
|---|---|---|
| Unit of billing | Tokens (in + out) | Calendar month or year |
| Cost at 10× traffic | ~10× | Unchanged |
| Surprise invoices | Common after launch | None |
| Best for | Experiments, pass-through billing, tiny usage | Production features with steady traffic |
| Typical Daymora price | n/a | $50/month |
When a flat-rate AI API is the better choice
Choose flat-rate when:
- AI is a core product feature, not a weekend prototype
- You need a number for a budget, runway model, or investor update
- Conversation history and long context actually improve the product
- You already spend close to $50/month on tokens and the trend is up
- You want one key for GPT-5, Claude Sonnet 4, and Gemini 2.5 Pro instead of three vendor accounts
When pay-per-token still wins
Stay on tokens when:
- Usage is near zero most months
- You bill end users per generation and want cost to track revenue
- You need a model or region a flat-rate platform does not offer
- You are evaluating prompts and will throw the integration away
Honesty matters here: a flat-rate AI API is not automatically cheaper at 100 requests a month.
What "fair usage" means
Flat-rate is not a promise of infinite tokens. Providers publish (or enforce) fair-use limits so a single key cannot exhaust shared capacity. For product teams, fair use is still a better contract than an unbounded token invoice — you design for a ceiling you can name, not a slope you cannot.
Daymora includes fair usage in the Developer Plan, commercial use, a 99.9% uptime SLA, and a 12-month price lock. Details: AI API pricing.
How to migrate from a token API
Treat it as an integration change:
1. Compare request/response docs — do not assume OpenAI shapes
2. Move secrets to environment variables
3. Point your server route at the new base URL and auth header
4. Shadow-test streaming and errors before cutover
Step-by-step: How to migrate your app to a different AI API provider and the Next.js integration guide.
FAQ
Is a flat-rate AI API the same as unlimited? No. It is a fixed price with fair usage, not a blank check.
Is Daymora an OpenAI wrapper billed per token? No. Daymora sells a subscription. You do not receive an OpenAI-style usage invoice.
Can I use it commercially? Yes — commercial projects are included on the paid plan.
Bottom line
A flat-rate AI API is infrastructure priced like SaaS: one bill, one key, models behind a REST call. If your AI feature is going to live in production, budget it like you budget the rest of the stack. If you are still exploring, tokens are fine until the meter starts to sting.