Synthflow alternatives

I run Reachkit, which sells cold email software and makes no phone calls, so you won’t find it in the list below. The prices come from each vendor’s own pricing pages and docs as of October 2026; where I lean on someone else’s figures, I say whose.

Synthflow changed who it sells to. Its pricing page now shows a single plan, Enterprise, with contracts that “start at $30,000 annually”. Its docs say the old Pro, Growth and Agency plans “are no longer sold”, and on September 15, 2026 it removed the tools agencies used to bill their clients inside the product. Which alternative fits depends on which of those changes sent you here:

• Month to month, no contract, no platform fee: Retell AI.
• One per-minute rate with the model built in: Bland.
• An engineer who wants to pick every provider: Vapi.
• An agency building agents for clients: Voiceflow.
• One receptionist line and no developer: Lindy.
• Lead callbacks handled for you, at a higher price: 11x.
• People on the phone instead of an AI: Reply.io.

Not sure you want to leave? The Synthflow profile walks through its contract terms and how its docs say usage is billed.

Retell AI is a voice agent platform for inbound and outbound phone work, with chat and text agents on the side. It’s named in at least five of the roundups on Google’s first page for “synthflow alternatives” (Retell publishes one of them) and shows up as a related search. It fits a small business or agency that liked Synthflow’s builder and wants to keep a visual editor without signing for a year.

Price (October 2026): pay as you go, no seats and no platform fee; the pricing page says “No minimums, no contracts”. Each minute stacks Retell’s $0.055 infrastructure fee, a voice ($0.015 for the standard ones), your chosen model, and $0.015 of US telephony when you dial from a Retell number. With GPT 5.1 at $0.04, my math lands at about $0.125 a minute. A Retell number is $2 a month, and Retell grants $10 of starting credit, once per email address. Since September 30, 2026, pay-as-you-go usage draws on prepaid credits.

Strengths:

• Up to 20 calls can run at once at no charge; each line past that is $8 a month.
• Two-way contact sync with GoHighLevel, HubSpot, Salesforce, Dynamics 365 and Zoho, set up inside Retell, which matters if your clients live in GoHighLevel.

Drawbacks: when the balance runs dry, calls stop unless auto recharge is on, and every test call is charged at production rates. Long prompts cost more too: past 4,000 tokens, Retell scales the billed duration up in proportion. Agencies should read the terms before reselling: they bar building “a substitute for, or intermediary layer on top of” Retell, though Retell also runs a Solution Partner program.

Versus Synthflow: both offer a flow builder, CRM connectors and phone numbers. Retell publishes its per-minute rates; Synthflow quotes yours after a sales call. See the Retell AI profile or Vapi vs Retell AI.

Bland sells voice agents to enterprises on a stack it built itself: its own speech recognition, language model and voice. It fits a buyer who wants enterprise paperwork like Synthflow’s but would rather start on a public price than a $30,000 contract.

Price (October 2026): two self-serve plans sit below Enterprise. Start needs no card and has no monthly fee; you pay $0.14 per talk minute, with a ceiling of 10 simultaneous calls and 100 calls per day. Build adds a $299 monthly fee and drops the talk rate to $0.12, raising the ceilings to 50 at once and 2,000 per day. Each Bland number is $15 a month, and every outbound attempt over Bland’s lines is charged at least $0.015. Whether carrier costs are extra depends on which Bland page you read: the homepage folds telephony into the rate, while the pricing page bills it separately.

Strengths:

• “No token charges”: the model is inside the rate, so a month is easy to price. By my math, 5,000 minutes on Build is $899, about 36% of the $2,500 a month that Synthflow’s floor works out to.
• Security paperwork for regulated buyers: SOC 2 Type I and II, PCI DSS, HIPAA eligibility with a signed BAA on Enterprise, and, since August 2026, FedRAMP 20x Class A status.

Drawbacks: Bland’s pricing page puts SMS, warm transfers, guardrails and the appointment scheduling node under Enterprise, which has no list price. You can’t choose an outside model, and public reviews are scarce: 5.0 from 11 on G2.

Versus Synthflow: both sell to enterprises and contact centers. Bland adds two self-serve tiers below that, while Synthflow starts at the contract. See the Bland profile or the Bland alternatives.

Vapi is a developer platform where each layer of a voice agent is your call: speech-to-text, model, voice and carrier, with your own API keys if you have them. It fits a team with an engineer who used Synthflow’s model and voice options and now wants full control over the stack, including what each piece costs.

Price (October 2026): Vapi keeps $0.05 per minute for hosting and passes each provider’s charge through at list price, with no markup. For 1,000 minutes, its own calculator lands between $82 and $129 before the carrier; dialing out over Twilio costs another $0.014 per minute. A new account opens with $5 in credit and 4 concurrent lines; paying $29 a month for the Core package lifts that to 10. HIPAA is a $2,000 monthly add-on that includes a BAA.

Strengths:

• The homepage lists contact-center systems Synthflow users know, Five9, Genesys and Avaya, next to GoHighLevel, HubSpot and Salesforce.
• Since August 31, 2026 you can launch outbound campaigns from the dashboard, each holding up to 10,000 contacts. Synthflow keeps its batch campaigns for Enterprise plans.

Drawbacks: the numbers Vapi hands out free are US-only and take inbound calls only, so any outbound calling needs a number you bring from a carrier. G2’s summary of its handful of reviews says the many options take technical knowledge, and Vapi’s small, unclaimed Trustpilot profile (2.4 from 15) includes complaints about pauses mid-call.

Versus Synthflow: Synthflow scopes one contract around your volume. Vapi itemizes every minute and leaves the choices to you. See the Vapi profile or the Vapi alternatives.

Voiceflow is a platform for building, testing and running AI agents for customer service, over chat and phone. It fits an agency that ran client agents on Synthflow’s subaccounts and wants a vendor that still sells to agencies directly.

Price (October 2026): Voiceflow’s pricing page shows no prices; its docs point to the app for current plan, add-on and credit prices. The plans are Free (a one-time credit grant that Voiceflow says isn’t meant for production), Pro, Business and Enterprise. The last prices Voiceflow published, in April 2025, were Pro from $60 and Business from $150 a month, with extra editor seats at $50. Macha, which sells a competing product, reported the same $60 and $150 base prices from the app in September 2026. Credits past the plan’s monthly allotment, extra phone numbers and extra concurrent calls are billed on top.

Strengths:

• The pricing page has an “Agencies & Partners” track promising “Multi-client workspace management”, “White-labeling and client handoff tools” and a free trial with no card. Voiceflow doesn’t spell out the white-label scope.
• Chat and voice share one builder, and calls can run on Voiceflow numbers or your own Twilio, Vonage or Telnyx account.

Drawbacks: with a plan fee, seats and usage stacked, the bill is hard to forecast before launch, and G2 reviewers flag usage limitations. The product leans to support conversations more than sales calls. Its changelog says calls are declined once credits run out, unless auto top-ups are on.

Versus Synthflow: Synthflow took client billing out of its product. Voiceflow markets client management to agencies and sells monthly plans below Enterprise. See the Voiceflow profile.

Lindy is a seat-priced AI teammate that lives in Slack, email and iMessage. Among its prebuilt roles is a receptionist: it picks up the phone, puts appointments on the calendar and sends a confirmation text. It fits a small business that used a Synthflow template for one inbound line and never needed a contact-center platform.

Price (October 2026): on October 18, Lindy’s pricing page started at $49.99 per user a month for 5,000 credits; earlier in the month it also showed a $29.99 entry for 3,000 credits. Seats are counted by use, so a colleague who only @mentions Lindy in Slack is billed too, after a 7-day trial. New accounts get $50 of credits for 7 days. What a phone minute or a number costs in credits isn’t published anywhere I found.

Strengths:

• You set it up by describing the job in plain English, with no API keys to manage.
• Hit the credit limit and Lindy holds credit-using work until your next cycle; its pricing page promises “no surprise bill”.

Drawbacks: Lindy’s own range for one task runs from 2 credits to 2,500, which makes a month’s spend hard to estimate up front. On Trustpilot it averages 1.7 across about 40 reviews, 78% of them one-star, with credits and billing the main theme.

Versus Synthflow: Synthflow is built to run large call volumes. Lindy is built for a small team’s everyday work, and answering the phone is one of the jobs it can take. See the Lindy profile.

11x sells AI agents for revenue teams. Julian, now mostly called Inbound on its site, is a voice and chat agent that rings each new form fill back in under a minute, qualifies the lead, and then books a meeting or hands the call to a rep live. It fits a sales team that used Synthflow for speed-to-lead and would rather buy that job finished than build it.

Price (October 2026): sales-led, on annual contracts. Julian’s Growth tier for voice is “Starting at $5,333 / mo”, billed annually, for 2,000 calls a month and 3 concurrent calls, with SMS and WhatsApp included. That’s about $64,000 a year, more than Synthflow’s floor. 11x says onboarding is included with no implementation fee. There’s no self-serve trial.

Strengths:

• Routing is built for sales teams: real-time scoring, territory, round-robin, named-account and seniority rules, and Chili Piper support.
• API access comes with every Julian tier, and Trustpilot reviewers often praise their customer success manager (4.3 from 38 reviews).

Drawbacks: the entry price is higher than Synthflow’s. Under 11x’s terms, what you’ve committed to pay can’t be cancelled and isn’t refunded, and there’s no way out for convenience. Julian’s Growth tier covers 2 languages, and 10 on Pro.

Versus Synthflow: Synthflow gives you a platform to build your own agent on. 11x sells one agent with the qualification and routing already designed around a sales funnel. See the 11x profile.

Reply.io runs multichannel sales sequences where a call can sit between an email, a LinkedIn touch, a text or a WhatsApp task; its AI SDR, Jason, is a separate purchase. It fits a sales team that ran outbound calls through Synthflow and decided the caller should be a person, with software choosing who to ring and when.

Price (October 2026): the Multichannel plan is $99 per user a month ($89 if billed yearly), and every seat comes with LinkedIn and Calls & SMS. Number rental, call minutes, texts and phone validation come out of a wallet you top up. Jason is extra, from $500 a month on yearly billing or $800 month to month. You get 14 days to try it; there’s no free tier.

Strengths:

• A call is just another step in the sequence, and condition steps can send a lead down a different path based on opens, replies or LinkedIn status. Reply.io’s October 6, 2026 update announced a Power Dialer for working through call lists.
• Capterra rates it 4.6 (95 reviews, checked October 2026), and its official MCP server has 70 tools at no extra charge (some calls use API credits), so an AI assistant can look up and act on your Reply.io data.

Drawbacks: the price climbs with every rep you add, and wallet charges for numbers and minutes land on top of the seats.

Versus Synthflow: with Synthflow the agent does the talking. With Reply.io a rep talks, and the software handles the list, the timing and the follow-ups. See the Reply.io profile or the Reply.io alternatives.

Begin with the change that pushed you, and put your real call script through two platforms before any phone number moves.

• Priced out by the contract. Cost out a typical month on Retell AI’s rate card and on Bland’s Start plan. At my lean Retell rate, Synthflow’s $2,500 monthly floor would cover about 20,000 minutes.
• Agency with client subaccounts. Look at Voiceflow’s agency track, or Retell AI if your clients run GoHighLevel. Synthflow’s docs list call data export, so pull logs and transcripts before you cancel.
• Contact center on Five9 or Genesys. Vapi lists both. Synthflow connects to them too, so if you need its SLAs and security review, its contract may still be the right buy.
• One line, no developer. Lindy.
• Sales callbacks. 11x if the budget is there; otherwise Retell AI with a CRM sync.
• Outbound to cold lists. Reply.io, with people making the calls (see the FAQ on consent).

One reason not to rush: Synthflow’s docs say existing Pro, Growth and Agency workspaces keep their limits, so a legacy account isn’t forced off today.

Synthflow’s move to Enterprise contracts makes sense for a contact center with Genesys, a security review and a large call volume. For the small businesses that wrote most of its G2 reviews, and the agencies that resold it, it closed the door. If that’s you, I’d test Retell AI first, and Bland if you’d rather have one rate. Agencies should give Voiceflow’s agency track a look. On a legacy plan, nothing forces you out yet, so export your call data and test calmly.

If those calls were meant to win new customers, I’d switch channels rather than vendors: start the conversation by email, the job Reachkit was built for, and let a voice agent call the people who write back. More in the Synthflow, Retell AI and Bland profiles.