Credits are what a workspace spends on AI work: every learner turn, voice minute, scored attempt and AI build draws from a single shared balance. Every workspace has a credit balance on every plan, and anyone in the workspace can see it on the Settings → Credits & Billing page. Buying credits and changing alerts are limited by role, as described below.
What uses credits
A workspace has a single balance. Everything its simulations and coaches do with AI is charged to it, whoever the learner is and wherever the simulation is embedded.
- Text turns: Each reply from a simulation character or a coach is charged from the AI usage of that turn: the text sent to the model and the reply it writes, with the reply weighted more heavily. A typical turn in a short text conversation costs about 6 credits. Turns cost more as the conversation gets longer, and more when the simulation or coach has knowledge documents attached. A welcome message that you wrote yourself is not charged.
- Voice sessions: Voice is charged at 120 credits per minute of session time, plus the AI usage of the character's replies. Voice uses credits much faster than text.
- Evaluation and scoring: Scoring an attempt against your criteria is a further AI call, charged when the attempt is scored. See Evaluation and scoring.
- AI help while you build: Generating a simulation or a coach from a description, translating into another language, drafting criteria from source materials, summarizing source materials, and generating a learner summary are each charged for the AI usage of that request.
- Conversation summaries: A short automatic summary of a finished simulation conversation, which linked coaches use, is charged a small amount.
Editing, publishing, embedding and viewing results do not use credits.
How a charge works
- Before any AI call, devlin.ai estimates the most the call could cost and holds that many credits from the balance. If the balance is lower than the estimate, the call is refused and nothing is charged.
- The AI call runs.
- The actual cost is charged and the rest of the hold is returned to the balance. A call that fails before the AI produced anything returns the whole hold. A reply that fails partway is charged only for the AI usage up to that point.
What follows from this:
- The balance can never go negative. A charge is also never more than the amount that was held for it.
- A turn can be refused while the balance still shows some credits, because the balance has to cover the estimate, which is higher than what a turn usually costs.
- A voice session holds the cost of a full-length session when it starts, based on the simulation's voice session length limit. The balance drops by that amount while the session runs, and the unused part comes back when the session ends.
When the balance cannot cover a charge
Nothing is charged, and the person using the feature is told it is unavailable. Learners are never shown anything about credits or billing.
- Text simulation: the learner's message gets no reply, the simulation ends, and the learner sees "This simulation is temporarily unavailable. Please try again later." The message is shown in the simulation's language.
- Text coach: the learner sees "This coach is temporarily unavailable. Please try again later."
- Voice: the session does not start. The learner sees "Voice mode isn't available right now" and "This voice session couldn't be started. You can continue in text mode instead." If the simulation or coach is set not to offer text when voice fails, the second line is "This voice session couldn't be started. Please try again."
- Scoring: the scoring run is refused.
- Building: generating a simulation shows "Not enough credits to generate." with a Purchase more credits link to this page. Other AI helpers show a similar message.
The workspace also gets an out-of-credits alert, described under Low-credit alerts below. A simulation can also stop for the day because it reached its own daily limit, which shows the learner a different message. See Daily spending caps for simulations and coaches.
Where credits come from and when they expire
Credits arrive as grants. Each grant has its own expiry date, and usage always draws from the grant that expires soonest.
- Sign-up credits: A new account's personal workspace starts with 1,500 credits. They never expire. A new organization workspace starts with no credits.
- Monthly subscriptions: Each paid renewal adds the plan's monthly credits. Each month's grant expires 3 months after it is added, so unused credits roll over for up to 3 months and are then removed. This applies to every plan billed monthly.
- Annual subscriptions: The whole year's credits are added up front when the year is paid, and expire 12 months later, plus 14 days of grace so that simulations keep working while a renewal payment is retried.
- Plans billed by invoice: The contract year's credits are added up front and expire 15 months after the contract period starts.
- Top-ups: Purchased credits expire 12 months after purchase.
- Credits added by devlin.ai: Bonus credits added to your workspace by devlin.ai do not expire.
Expired credits are removed from the balance by a daily check, so a grant can stay usable for a short time past its expiry date.
Subscription credits are added when a payment is collected: at checkout, at each renewal, and when a change of plan or billing cycle starts a new paid term. One exception: when a Starter subscription is upgraded to Core on monthly billing using a free trial granted by devlin.ai, the Core credits are added at the upgrade, before anything is charged. On a subscription billed through Stripe, adding a seat in the middle of a billing period does not add credits until the next renewal. Cancelling a subscription or moving to the Free plan does not remove credits you already have. They stay until they are used or expire.
How many credits each plan includes is covered in Plans and what each includes. Renewal dates, switching billing cycle and cancelling are covered in Changing, switching or cancelling a subscription.
The Credits & Billing page
Open Settings and select Credits & Billing. The page describes the workspace that is active, so switch workspace first if you belong to more than one. See Workspaces. The balance in the top bar of the dashboard links to the same page.
In an organization workspace, every member can open the page and see the balance and the transaction history. What else appears depends on your role and the plan.
- Credits: the heading shows Current balance: with the workspace's credits.
- Credit Top-Ups: the credit packs you can buy. Shown on the Core, Team, Enterprise plans, and in an organization only to the owner.
- Low Credit Alerts: the alert thresholds and the email switch. Shown on every plan except Free.
- Simulation Spending Limit: the workspace's default daily cap. Shown to owners and admins. See Daily spending caps for simulations and coaches.
- The current plan, or the plans you can subscribe to. See Plans and what each includes.
- Receipts: a receipt link for each of the most recent 100 payments, and an invoice PDF for subscription payments. The section appears once the workspace has started a Stripe checkout. In an organization only the owner can open receipts. Admins and members see a note naming the owner.
- Transaction History: credits added and credits used. Credits removed at expiry are not listed.
Transaction history
The table's columns are Date, Credits and Description.
- Credits that were added, such as a subscription grant or a top-up, each appear as their own row with a plus sign and a description of the grant.
- Usage is grouped into a single row for each day, labelled Credits used, with the day's total. Days follow your browser's time zone.
- Select a usage row to expand it. The breakdown lists each simulation and coach that used credits that day, the credits each used, and the kind of usage, for example chat, voice or evaluation. Usage that does not belong to a particular simulation or coach is listed by kind.
Credits that were held for a call and then returned are not listed, because they were never spent.
Buy a credit top-up
Top-ups are separate purchases on top of the plan's credits.
- Plans: top-ups are available on the Core, Team, Enterprise plans. On the Starter plan the Credit Top-Ups section tells you to upgrade to Core to add credits. On the Free plan the section is not shown, and a purchase is refused with "Credit top-ups are available on the Core, Team and Enterprise plans".
- Role: in a personal workspace, you. In an organization workspace, only the owner. Admins and members do not see the packs, and a purchase by them is refused with "Only the workspace owner can purchase credits for this organization".
The packs are:
| Credits | Price |
|---|---|
| 10,000 | $29 |
| 100,000 | $249 |
| 500,000 | $1,099 |
To buy one:
- Open Settings → Credits & Billing.
- Under Credit Top-Ups, select Get Now on a pack.
- Pay on the Stripe checkout page.
You are returned to the page with the banner "Credits added to your account!". The credits are added as soon as Stripe confirms the payment, the purchase appears in Transaction History, and its receipt appears under Receipts. Top-up credits expire 12 months after purchase.
Low-credit alerts
devlin.ai alerts the workspace the moment a charge takes the balance below one of its alert thresholds, and again when something is refused because the credits ran out.
Thresholds
A workspace has a list of up to 5 thresholds, each a number of credits. Until you set your own, the plan's defaults apply:
| Plan | Default thresholds (credits) |
|---|---|
| Free | 500 |
| Starter | 2,000, 1,000, 500 |
| Core | 10,000, 5,000, 1,000 |
| Team and Enterprise | 100,000, 50,000, 10,000 |
A workspace on the defaults follows its plan: when the plan changes, the thresholds change with it. A custom list stays as you set it.
Set your own thresholds
You need a plan other than Free: on that plan the Low Credit Alerts section is not shown. In an organization workspace you need to be the owner or an admin. Members see the section, but saving is refused with "Only owners and admins can change alert settings for this organization".
- Open Settings → Credits & Billing and find Low Credit Alerts.
- Under Alert thresholds (credits), edit a value, remove one with the ✕ button beside it, or select + Add threshold. The label shows "(your plan's defaults)" until you change something. The list cannot be emptied: the last threshold has no remove button.
- To stop the emails, clear Email workspace owners and admins for these alerts.
- Select Save. The page shows "Saved!".
Thresholds must be positive whole numbers. Duplicates are dropped and the list is sorted from highest to lowest when it is saved. Reset to plan defaults saves immediately and returns the workspace to its plan's defaults.
Who is alerted
- In the app: every member of the workspace gets a notification in the bell. This cannot be turned off.
- By email: the owner and the admins of the workspace each get an email with the threshold that was crossed and the balance. In a personal workspace that is you. The email is sent unless Email workspace owners and admins for these alerts is cleared. The switch applies to the whole workspace, not to an individual. The unsubscribe link in the email, once confirmed by an owner or admin, clears the same switch for everyone.
This switch is separate from your marketing email preference: opting out of product emails does not stop low-credit alerts, and stopping low-credit alerts does not change your other emails.
When an alert fires again
- A threshold fires when a charge moves the balance from at or above it to below it. If one large charge crosses several thresholds at once, you get a single alert, for the lowest threshold crossed.
- A threshold is ready to fire again as soon as the balance is back above it, for example after a top-up or a renewal. Nothing needs to be reset.
- A threshold does not alert again within 24 hours if it was the most recent threshold to alert. If you top up and cross that same threshold again inside the window, the second crossing is silent. If a different threshold alerted in between, it can alert again.
- A daily check also alerts a workspace whose balance is below its highest threshold, for example because credits expired, if no low-credit alert has gone out since credits were last added by a subscription payment, a top-up, devlin.ai or an invoiced plan. Every member gets the notification, and the email goes to the workspace's own email address.
Out-of-credits alert
When a learner turn, a voice session, a scoring run or a build is refused because the balance cannot cover it, every member gets the notification "A session was declined: your workspace is out of credits." and the owner and admins get an email, unless the email switch is cleared. This alert is sent at most once every 24 hours, and never for a workspace that has not received any credits yet.
The older single threshold
Workspaces also carry an older setting that holds a single threshold. Alerts no longer read it: they use the list described above, and the page edits only the list. A workspace that had customized the single threshold before the list existed was given a list containing only that value.
AI tools over MCP
An AI tool connected through the MCP server can read the workspace's credit usage with get_credit_usage. It returns the plan, the current balance, the number of seats, the credits used so far this calendar month (counted in UTC), and the 10 most recent transactions with their type, amount, description and date. It is read-only. An AI tool cannot buy credits, change the plan or change alert settings: those are done by a person on the Credits & Billing page.