In this guide
How can agencies replace Synthflow's removed Stripe rebilling?
Assistable replaces Synthflow's removed in-product usage rebilling with agency-set client prices, Stripe-funded prepaid wallets and a client billing portal on Startup, Growth and Agency. It is a strong fit for agencies selling branded voice and chat services with HighLevel workflows. For monthly client subscriptions with included minutes and overage, compare the explicitly documented package features of Autocalls or ChatDash. You can also keep Synthflow and operate billing externally. These models are different: a wallet top-up is not a recurring subscription or a monthly minute allowance.
Key points
- Client price and platform cost are different
- Two balances to operate
- Model the complete cost
Start with the way you charge your clients.
A wallet, an included-minute package and a recurring invoice serve different offers. Match the payment mechanism to what you sell before comparing prices. This Assistable-authored comparison uses the linked provider documentation.
| Your client offer | Options to evaluate | Verify before choosing |
|---|---|---|
| Prepay for usage at my rates | Assistable: Stripe-funded wallets, configurable usage prices and branded client accounts. Stammer also documents subaccount wallets. | Billable categories, client access, top-up behavior and who funds the platform's separate costs. |
| Pay monthly for included minutes, then overage | Autocalls publishes client included-minute plans. ChatDash documents subscriptions with a base fee, usage limit and overage fee. | Allowance reset, renewal timing, usage rounding, failed-payment behavior and underlying provider charges. |
| Pay a retainer or recurring invoice | Trillet documents one-time and recurring invoices. Separate Stripe billing can also collect retainers alongside a usage platform. | Which charges are automatic, which invoices need review, and how usage beyond an allowance is calculated. |
| Keep my working Synthflow agents | Use Synthflow's API or call data with your own customer billing system. | Metering, renewal boundaries, reconciliation, collection and customer-facing reporting. |
Keep the agent. Or bring billing into your agency platform.
The right choice depends on how much commercial infrastructure you want to maintain. Keeping Synthflow preserves a working deployment, but its removed customer billing does not return just because you have a Stripe account.
| Responsibility | Synthflow with external billing | Assistable usage rebilling |
|---|---|---|
| Client price | Maintain prices, subscriptions or invoices in your billing system. | Configure supported client usage rates in Assistable after connecting Stripe. |
| Usage | Collect API counters, post-call durations or call-history totals and reconcile the billing period. | Platform usage is charged against the client wallet at configured rates when rebilling applies. |
| Payment | Own invoice collection, payment failures and any prepaid-credit logic. | Clients fund their wallet through the connected Stripe setup and can configure auto top-ups. |
| Agency cost | Pay Synthflow under your agreement and reconcile that bill against client revenue. | Maintain a separate agency wallet for platform costs. Client funds do not automatically refill it. |
| Recurring packages | Build monthly retainers, included usage and trials in the billing system you choose. | Review recurring retainers or bundled packages separately from documented usage-wallet rebilling. |
| Client reporting | Replace the removed subaccount billing and usage pages with your own reporting. | Review the client wallet and billing experience in the pilot with the intended permissions. |
Know which balance pays for what.
A client balance and an agency balance serve different purposes. The client funds the service at your configured prices. Your agency pays Assistable for the underlying platform usage. Keeping those two flows visible prevents a healthy client balance from hiding an underfunded agency account.
Connect your agency's Stripe account
Authorize Stripe in Assistable and confirm the correct business account and payment configuration.
Set the client's usage prices
Choose supported fixed prices or markups for the usage categories you sell. Confirm category-specific rules in the billing guide.
Enable the client account
Apply rebilling to the intended subaccount, confirm membership/access and review its wallet setup.
Fund and monitor both balances
The client funds its prepaid wallet and configures any automatic top-up. Your agency separately maintains its platform wallet and monitors exceptions.
A client charge is not your profit.
Illustrative example, not a quoted rate: suppose an authorized test produces $10.00 of underlying voice usage cost. At a 50% usage markup, the client charge is $15.00. The $5.00 difference is a usage spread, before your agency subscription, payment fees, support and other costs.
- Enable both the subaccount rebilling switch and the relevant usage categories. With every category switched off, usage is not rebilled to the client.
- The current billing guide documents fixed-price or percentage rules by category. Knowledge-base lookups have a specific percentage/pass-through rule; do not apply one blanket price to every category.
- Validate the actual client receipt, agency cost and supported rounding in your pilot. Add your complete operating costs in the worksheet before setting a client price.
| Record | What the example shows |
|---|---|
| Client wallet | $15.00 deducted for the rebilled usage. A previous wallet deposit funds this balance; it is not a second usage charge. |
| Agency wallet | $10.00 deducted for the underlying usage. Client payments do not automatically replenish this separate balance. |
| Usage markup | $5.00 / $10.00 = 50% of cost. |
| Usage margin | $5.00 / $15.00 = 33.3% of revenue before other costs. A 50% markup is not a 50% margin. |
Know what your agency keeps.
Model the usage spread, then account for the costs of delivering the service. Change every assumption to match your business.
After the costs entered. Before tax and any unmodeled costs.
- Client usage revenue
- $2,500.00
- Variable usage cost
- $1,050.00
- Platform subscription
- $225.00
- Support & other costs
- $300.00
- Payment processing
- $77.50
Both ratios are before subscription, delivery and payment costs. They are not net profit.
What is included in this example?
The illustrative $0.105/min cost combines $0.050 orchestration, $0.020 Standard TTS, the $0.020 Kimi K2.6 model and $0.015 Assistable telephony, using the published rate sheet reviewed October 17, 2026. Your selected plan or proposal governs the actual price. Add other usage, carrier fees, phone rental and per-call adjustments to your inputs.
The $225 subscription comes from the published Startup agency offer. The client price, delivery costs and payment fees are editable assumptions, not published customer results or a Stripe quote. This model uses usage revenue, not wallet deposits, and excludes retainers, taxes, refunds, bad debt and costs you have not entered.
The modeled break-even rate divides usage, subscription, delivery and fixed payment costs by the entered minutes, adjusted for the percentage payment fee. It changes when your volume or assumptions change. The CSV includes the inputs, results, formula and source notes so your team can review the same scenario.
Calculations run in your browser. There is no form submission.
Price the whole service, not one line on the rate sheet.
An advertised voice rate may cover only part of a conversation. Compare plan fees and usage at the same scope before deciding what to charge clients or what a move could save.
- Use your actual Synthflow agreement for the current-cost baseline. The published enterprise minimum is not every existing customer's bill.
- Assistable's agency subscription does not make all voice minutes, models, carriers or optional features free.
- Client wallet deposits are not automatically earned revenue. Keep prepaid balances, consumed usage and recognized service revenue distinct in your accounting.
| Cost | What to include |
|---|---|
| Platform plan | Your agency subscription and any account, capacity or feature allowances. |
| AI conversation | Orchestration, selected speech and language models, and enabled add-ons. |
| Telephony | Carrier usage, transferred-call behavior, number rental and applicable messaging costs. |
| Payments | Payment processing, refunds, failed collections and any billing-system charges. |
| Delivery | Setup, support, monitoring and the work required to operate the client account. |
If you stay on Synthflow, give billing an owner.
Synthflow documents three ways to measure client usage: the subaccount minutes_used counter, call durations from post-call webhooks, or totals from call history. Choose a reliable source, define each client's billing window and reconcile it before issuing charges.
- Keep a mapping between client, Synthflow subaccount and billing customer.
- Define the renewal timestamp, time zone, usage allowance and overage price for each agreement.
- Make ingestion and invoice generation safe to retry so the same usage does not create duplicate charges.
- Reconcile usage before resetting a counter. A reset is not an invoice or proof of payment.
- Decide what a failed payment or usage limit does to the service, and communicate that policy to the client.
Plan for the payment that does not go through.
Automatic top-ups still depend on a valid payment method and successful collection. Give someone responsibility for the exception, not just the setup. Confirm how the approved customer policy matches the account's actual behavior.
| Situation | What to check | Operating decision |
|---|---|---|
| Client cannot see Billing | Membership and account access. Assistable's client-wallet guide requires a member invitation. | Invite the intended billing owner and verify access from their view. |
| Client payment fails | Payment status, remaining balance and top-up configuration. | Assign the notification, recovery and customer communication process. Do not assume a failed payment is recovered automatically. |
| Client balance runs out | The v3 billing guide says an in-progress call can finish and leave a negative client balance. Auto top-up still depends on successful payment. | Treat the wallet as a funding mechanism, not a guaranteed hard spend cap. Verify account and service behavior in the pilot. |
| Agency wallet is underfunded | The agency-wallet guide warns that a negative balance blocks voice calling across subaccounts. | Maintain agency funding separately; client balances do not remove that responsibility. |
| Old and new billing overlap | Both billing systems, invoice periods, credits and active subscriptions. | Confirm one intended collection path for each charge and reconcile before expanding. |
Move the billing relationship deliberately.
Your Stripe customers, active subscriptions, stored payment permissions, credits and client contracts are not automatically migrated by creating an Assistable account. Map the commercial arrangement first and approve the next charge with the correct billing owner.
Reconcile the old period
Record what was billed, paid, used, credited and still owed. Preserve the evidence needed for customer questions.
Configure the new relationship
Set the client rate, wallet policy and any separate retainer. Review customer notices and payment authorization requirements.
Test the billing path
With authorization, validate the intended payment and usage flow, correct client ledger and separate agency charge. Check failure behavior as well as success.
Stop duplicate collection
Agree on the old subscription end and new start. Verify the first reconciled period before expanding to more clients.
Plan the billing handoff.
22 acceptance checks covering access, billing, the pilot and cutover. Assign an owner, record evidence and confirm each pass condition before moving a client. Open the CSV in your spreadsheet tool. No email required.
Download migration checklistCommon questions
Which Synthflow alternatives support agency client rebilling?
Assistable supports Stripe-funded prepaid usage wallets with your own client prices on Startup, Growth and Agency. Stammer also documents client wallets. For recurring client packages with usage allowances and overage, evaluate Autocalls or ChatDash. Trillet documents recurring invoicing. Start with the billing mechanism your offer needs, then compare client delivery, CRM actions and total cost.
Can I reconnect Stripe to Synthflow for rebilling?
Synthflow's current documentation says the in-product reselling integration was removed on September 15, 2026 and new Stripe connections are no longer supported. You can use your own Stripe account externally to bill customers.
Does Assistable automatically refill the agency wallet from client payments?
No. The documented client and agency wallets are separate. Client payments fund the client balance, while your agency must maintain its own platform-usage balance.
Can I set my own client prices in Assistable?
Yes, on eligible agency plans with rebilling configured. Supported usage categories have fixed-price or percentage-markup rules. Review the current billing guide for each category before setting an offer.
Can Assistable sell monthly client plans with included minutes and overage?
Assistable's native rebilling charges prepaid usage. Treat monthly subscriptions, included-minute accounting, renewal resets and overage rules as separate billing requirements. Collecting a retainer separately does not automatically create those rules, and Synthflow's former client plans do not import automatically.
Is Synthflow Auto-overage the same as collecting customer payments?
No. Auto-overage keeps the subaccount calling beyond its allocation, but Synthflow charges the agency. The agency must track and bill that usage to its client separately.
Can I calculate savings from advertised per-minute rates?
Only if the rates cover the same components. Include models, speech, telephony, optional features, plan fees, numbers and delivery costs. Use current agreements and actual bills for the comparison.
What if my client cannot see their wallet or billing settings?
Assistable's client-wallet documentation requires the client to be invited as a member of the intended account. Verify the invitation, membership and account context before changing billing configuration.
Does a client wallet guarantee a hard spending cap?
No. Assistable's v3 billing guide says a call already in progress can finish and leave the client wallet negative. Top-ups depend on a successful payment, and the agency wallet remains separate. Validate the account's current balance and service behavior, and set an operating policy for payment failures before rollout.
Sources & review notes
Reviewed October 17, 2026. Published by Assistable.ai, a provider included in these comparisons. Official documentation establishes the stated features and changes; it does not establish migration results. Confirm your account-specific terms with the relevant provider.
- Synthflow: reselling migration
Removal date, affected features, retained controls and external billing options.
- Assistable: usage rebilling
Stripe setup, client prices, subaccount activation and defaults.
- Assistable: client wallet
Prepaid balance, payment method and automatic top-up configuration.
- Assistable: agency wallet
The agency funds a separate platform-usage ledger.
- Assistable: agency plans
Current plan eligibility and account allowances. Usage is additional.
- Assistable: Stripe integration
- Assistable: usage billing rules
- Autocalls: included-minute client plans
- ChatDash: subscriptions and overage
- Stammer: subaccount usage wallets
- Trillet: recurring invoices
- Synthflow: limits and Auto-overage
- Synthflow: billing and existing agreements
- Stripe: usage-based billing