One week of coding classes, one SwiftRelay balance
Picture the week: a teacher opens a coding club, helps students debug their first programs, and needs a dependable way to bring model-powered exercises into the lesson without managing a stack of subscriptions. SwiftRelay is designed for that kind of practical setup. It is a pay-per-token API relay: you top up a balance, and each call deducts only what it used. There is no monthly fee and nothing to subscribe to, so a teacher can start small, watch the usage, and decide what the class actually needs.
The promise is deliberately simple. SwiftRelay is connected in minutes: copy three lines and run. That is a useful starting point for a busy teacher who wants the demonstration to work today, not after a procurement conversation. The service is available through the API host https://api.fastapirelay.com, and your account can hold up to 20 live API keys. That gives you room to separate a classroom key from a staff key, or to rotate keys when a session ends.
New accounts receive $0.22 in sign-up credit. It is not a plan, a pass or a card. It is simply credit on the balance, ready to put a small first experiment in front of students. Once the class is running, the dashboard shows tokens and cost per call, which turns “the model used some tokens” into a number a teacher can discuss with learners.
Connecting the classroom in three lines
For a class that uses Claude models, the setup begins in the official Claude Code or Claude Desktop client, version 2.1.285 or later. The point of the quick start is that the configuration is short and repeatable. You can prepare it once, show the same pattern to students, and focus the lesson on the code rather than on account administration.
Here is the Claude Code configuration:
01 export ANTHROPIC_BASE_URL=https://api.fastapirelay.com 02 export ANTHROPIC_AUTH_TOKEN=<your swft_ key>
claude
Those three lines are the whole connection story: point the client at the SwiftRelay API host, provide your swft_ key, and launch the client. The key is the classroom’s handle on the relay. Because SwiftRelay uses per-token billing, the top-up is the budget you control, and the usage list tells you what each call consumed.
For lessons built around Gemini models, the route is different: Gemini uses its native protocol through Gemini CLI. The configuration is just as compact:
01 export GOOGLE_GEMINI_BASE_URL=https://api.fastapirelay.com 02 export GEMINI_API_KEY=<your swft_ key>
gemini
For OpenAI-compatible clients, the base URL is https://api.fastapirelay.com/v1, with a swft_ key used as the API key. That is the route for clients that work with GPT, DeepSeek and other remaining models. The important classroom habit is to keep the pairing clear: choose the client and model family that belong together, then let SwiftRelay handle the relay and the usage accounting.
A worked example: what one lesson call can cost
Here is an example, not a quotation for a particular student or class. Suppose one exercise sends 100,000 input tokens, receives 20,000 output tokens, and reads 50,000 cache-read tokens. Using the SwiftRelay pricing page prices for DeepSeek V4 Flash, the sum is shown line by line below.
- Input: 100,000 ÷ 1,000,000 × $0.2639 = $0.02639
- Output: 20,000 ÷ 1,000,000 × $1.06 = $0.0212
- Cache read: 50,000 ÷ 1,000,000 × $0.006944 = $0.0003472
- Example total: $0.02639 + $0.0212 + $0.0003472 = $0.0479372
That worked example gives a teacher a clean way to explain per-token billing. The input price applies to the prompt, the output price applies to the response, and the cache-read price applies to the cached portion. The dashboard lists tokens and cost per call, so students can compare a short debugging request with a longer design discussion and see where the difference comes from.
Now run the same example with GPT-6.1 Sol, again using the stated example token counts. The arithmetic is:
- Input: 100,000 ÷ 1,000,000 × $0.1736 = $0.01736
- Output: 20,000 ÷ 1,000,000 × $0.8542 = $0.017084
- Cache read: 50,000 ÷ 1,000,000 × $0.0347 = $0.001735
- Example total: $0.01736 + $0.017084 + $0.001735 = $0.036179
These are examples for teaching purposes, not a promise about the cost of every lesson. They do, however, show the value of a balance-based approach: you can plan a session, watch the calls appear, and top up when needed instead of committing to a recurring arrangement before you know how the group will use the models.
Choosing a top-up that fits the school week
SwiftRelay sells no plans. Its top-up options are $1.39, $6.94, $13.89, $27.78, $69.44 and $138.89. A teacher can start with the smallest amount for a quick demonstration, or choose a larger balance for a week of exercises or a larger group. The balance is not a subscription with a renewal date; it is the amount available for calls, and each call deducts only what it used.
That makes the first week feel manageable. Use the $0.22 sign-up credit to confirm the connection, then decide whether a $1.39 top-up is enough for the next classroom activity or whether a $6.94 top-up gives students more room to experiment. The usage list provides the feedback loop: check tokens and cost per call after each exercise, and adjust the prompt length, the model choice or the number of demonstrations based on real usage.
The balance model also keeps the lesson focused on learning. Instead of asking students to sign up for separate services, a teacher can explain one shared workflow: copy the configuration, use the key, make a call, read the usage. The class can spend its attention on debugging loops, writing functions, reviewing output and discussing why a response cost what it cost.
Keeping the balance, the keys and the support tidy
A week with SwiftRelay should end with a tidy handover. The account supports up to 20 live API keys, so a teacher can keep the classroom’s key distinct from other keys and remove or replace one when the teaching term changes. The dashboard’s usage view is the place to check which exercises generated calls and what those calls cost.
Support is available through Messages in the dashboard, where login is required. There is no support email to hunt for, so the fastest route is the same place where you review usage and manage the balance. For a teacher, that is a short path from “something did not run” to a question about the configuration.
The refund policy adds another piece of control. Unused credit can be refunded within 11 days of a top-up, minus what was used and the payment fee. For a careful first purchase, that means the decision to keep a larger balance can be made with the policy in view.
There is also a referral option for teachers who recommend the service to colleagues. A person you invite contributes 14% of each top-up to your rewards, and people they invite contribute 3%. Rewards can be withdrawn, with a minimum withdrawal of $4.86, or moved into the balance. It is a way for a school team to share a tool without turning the discussion into a sales pitch.
Stopwatch, pit stop, first run
By Friday, the classroom workflow can be as neat as a clean first lap: top up the balance, copy the three lines, run the client, and read the tokens and cost per call. SwiftRelay keeps the commercial side small, with no monthly fee and nothing to subscribe to, while giving teachers a practical way to bring model-powered coding exercises into a real lesson. Sign up for SwiftRelay today and take your coding class from first configuration to first successful run in minutes.