vapi gives developers control over the speech recognition, language model, and voice behind an agent. it handles the call infrastructure while you connect the agent to your own tools and business systems.

but there are other ways to build and run a voice agent. some platforms bundle speech and model usage into one rate, charge a fixed monthly price for call capacity, or offer visual editors for conversation flows.

we've compared vapi alternatives for customer support, outbound calling, and voice conversations inside your app. this guide breaks down what each platform does well, what it costs, and who should use it.

1. rumik silk

• product type: text-to-speech api and hosted voice-agent platform

• recommended users: teams running regular customer calls who want monthly agent pricing based on simultaneous calls

• pricing options: pay as you go and unlimited monthly plans

what is rumik silk?

rumik silk (that's us) is a voice platform for building ai receptionists, appointment booking agents, lead qualification agents, and order tracking agents. your agents answer incoming calls, place outbound calls, and talk to customers on your website.

you choose a voice from our mulberry and muga models and tell the agent how to handle the conversation. it also talks to your business systems through custom tools.

key features

• customer data and actions: before-call tools retrieve details for the greeting and instructions. during-call tools look up records or send updates to your backend as the conversation progresses.

• phone and web calls: the same configured agent takes browser calls, answers a phone line, and places outbound calls. a real-time audio socket also connects the agent to your own application.

• outbound campaigns: schedule calls to a contact list from your own number, personalize each conversation with contact details, and retry unanswered calls. transcripts and recordings show what happened on each call.

• drafts and deployments: changes to the agent stay in a draft until you deploy them. previous versions remain available to restore when you need to roll back a change.

how does rumik silk compare to vapi?

the tts row covers speech generation outside agent calls. silk has a standalone synthesis api as well as hosted agents. vapi's voice settings configure speech within its agents.

switching means recreating instructions, variables, tools, and phone routing in silk. an existing backend endpoint still needs the correct request and response mapping. vapi remains relevant when choosing speech recognition, language models, and voice providers independently is central to your setup.

rumik silk pricing

silk has pay-as-you-go agent pricing and unlimited monthly plans. the tables show its published regional prices: inr for india and usd for rest-of-world accounts. these are separate regional rates.

pay as you go

you pay for actual call duration, with no monthly subscription. pay as you go allows four simultaneous requests, shared across text to speech and agents.

unlimited monthly plans

the monthly fee covers unlimited agent minutes and text-to-speech generation. you pay for how many calls or speech requests run at once. a two-slot plan runs two calls, or one call alongside one tts request. requests above that shared capacity are rejected, with no credit overflow.

phone-number rental and carrier charges are extra on both billing options. rumik rents indian +91 numbers with business kyc. bring-your-own sip supports indian mobile +91 numbers.

when should you choose rumik silk?

• you have regular calls and a known concurrency requirement. choose a monthly plan around the number of calls that run together, and pay a fixed agent fee as the minutes accumulate.

• your customer workflow already has apis. connect the agent to your order, account, or support system, and keep those business actions in your backend.

• you run scheduled outbound campaigns. upload your contacts, personalize calls with customer details, and retry unanswered calls.

• you need text to speech and voice agents in the same stack. use mulberry and muga for standalone speech generation and customer calls.

create an agent in the silk playground and test it with your own greeting and customer questions.

bottom line

choose rumik silk as your vapi alternative when you need text to speech and voice agents in the same stack. you get mulberry and muga for both, plus monthly plans that cover unlimited speech generation and agent minutes at a fixed shared capacity.

2. retell ai

• product type: hosted voice and chat agent platform

• recommended users: teams that want to map call logic in a visual editor and test changes against saved scenarios

• pricing options: pay as you go and custom enterprise pricing

what is retell ai?

retell ai is a platform for building, testing, and running voice agents on the phone and web. you give the agent its job in a single prompt or map the conversation as connected steps in a visual flow.

key features

• conversation flows: combine dialogue, function calls, logic checks, and transfers. reusable subflows let you share a sequence across agents instead of rebuilding it each time.

• human handoffs: warm transfers let the agent brief the person receiving the call before connecting the caller. phone transfers work with retell-managed and imported numbers.

• knowledge and business actions: attach documents, website pages, or synced knowledge sources for answers. custom functions connect the agent to your apis for actions during the conversation.

how does retell ai compare to vapi?

both platforms generate speech during agent calls. the tts row refers to standalone audio generation outside those calls.

retell's flow editor makes the sequence of questions, actions, and handoffs explicit. vapi organizes conversations through assistants, tools, and squads. switching means rebuilding your prompts, tool definitions, and routing around retell's structure.

custom-llm agents use your own websocket response server. they support web and phone tests, but not retell's text playground, simulation tests, or batch tests.

retell ai pricing

retell's pricing is usage-based, with custom enterprise terms. these published usd rates show one voice-agent configuration:

pay as you go includes 20 simultaneous calls per workspace. additional capacity costs $8 per simultaneous call per month. retell-managed numbers cost $2 per month and are available for the us and canada. other number geographies need a supported custom-telephony setup.

telephony and add-ons are extra. knowledge-base retrieval adds $0.005 per minute, and batch calling adds $0.005 per dial. your carrier's charges still apply when you bring your own telephony.

when should you choose retell ai?

• your call has steps that need separate rules. use flow nodes for qualification questions, api actions, and routing, with a condition for moving between them.

• your phone agents regularly hand calls to people. configure a warm transfer that briefs the recipient before connecting the customer.

• you revise call behavior frequently. keep saved scenarios for difficult conversations and rerun them after prompt or flow changes.

bottom line

choose retell ai as your vapi alternative when your team needs to see and edit each stage of a call in a visual flow. the tradeoff is maintaining those nodes and transitions as your call logic changes.

3. bland ai

• product type: voice-agent platform and text-to-speech api

• recommended users: teams running phone workflows that want a bundled ai minute rate and staged agent releases

• pricing options: usage-based start and build plans, custom enterprise pricing

what is bland ai?

bland ai is a platform for agents that answer incoming calls and work through outbound call lists. you give an agent its job in a prompt, then add pathways for parts of the conversation that need their own questions, rules, or actions.

key features

• conversational pathways: give a branch its own instructions, tools, and routing condition. the agent enters that pathway when the conversation matches the condition you set.

• tools and knowledge: connect webhook tools to your apis and attach documents, websites, or other knowledge sources. reference the tools in the prompts that need them.

• versioned releases: keep updates in development and staging while production serves a pinned version. evaluations can act as required checks before promotion.

how does bland ai compare to vapi?

bland has both an agent platform and a standalone speech api. browser voice calls use its web agent sdk. channel access still depends on the plan, with web chat listed as an enterprise feature on the standard plans.

bland ai pricing

bland's pricing bundles the language model, speech recognition, and voice generation into the agent-minute rate. carrier usage is extra. the prices below are in usd.

transfers on bland-provided numbers cost $0.05 per minute on start and $0.04 on build. bring-your-own-telephony customers do not pay bland's transfer fees. outbound attempts using bland's telephony have a $0.015 minimum charge. warm transfers require enterprise on these standard plans.

the separate agent phone plan costs $29.99 per month at its regular rate for bots calling us and canada destinations. limits include one active call, 50 calls per day, and 1,000 call minutes per day.

standalone bland speech usage has separate per-character billing.

when should you choose bland ai?

• you want one ai rate for phone calls. budget for the language model, speech recognition, and voice generation together, then add your carrier costs.

• agent updates need a release process. test a version in staging and use evaluation checks before promoting changes to production.

• your deployment needs private infrastructure. bland lists on-prem and vpc deployment options under enterprise, with terms agreed for your setup.

bottom line

choose bland ai as your vapi alternative when you want one rate for the language model, speech recognition, and voice generation, plus staged releases for call-flow changes.

4. synthflow

• product type: enterprise voice and chat agent platform

• recommended users: teams connecting voice agents to an existing phone operation

• pricing options: custom annual enterprise agreement

what is synthflow?

synthflow is a voice-agent platform for teams adding ai to an existing phone operation. you build the conversation in prompt builder or flow designer, connect business actions, and deploy through a phone number or website voice widget.

key features

• call flows and business workflows: flow designer controls the conversation through nodes and branches. the separate workflow builder handles events around the call, such as triggering outbound calls or sending results to another system after hangup.

• custom actions: run http requests before or during a call. map the values the request needs and configure what the caller hears while it runs.

• existing telephony: connect your twilio account or an approved carrier or pbx through sip. your workspace region and phone-system configuration determine the connection settings.

how does synthflow compare to vapi?

synthflow's model selector supports its own llms and listed gpt models. custom llm endpoints aren't supported there, so a custom response server used with vapi does not carry over.

switching also means rebuilding prompts, action mappings, and phone routing. prompt builder and flow designer are separate modes: moving an agent between them requires rebuilding it.

synthflow pricing

synthflow's pricing is a custom annual enterprise agreement. the quote is scoped around call volume, simultaneous calls, telephony, integrations, security requirements, and support. new customers start on enterprise, with no free plan or trial.

included usage, carryover, overage, and telephony charges follow your agreement. completed simulations are tracked separately from live calls and billed according to your workspace terms. launch support is included when agreed in the contract.

when should you choose synthflow?

• you already run a contact-center phone system. connect your approved carrier or pbx over sip and plan routing, handoffs, and capacity around that setup.

• your team needs to edit call and business logic visually. use flow designer for the conversation and workflows for the actions around it.

bottom line

choose synthflow as your vapi alternative for an enterprise rollout that connects your phone system to visual call flows and business workflows.

5. elevenlabs

• product type: text to speech and hosted voice agents

• recommended users: teams building around elevenlabs voices who want agent workflows and actions inside their app

• pricing options: pay as you go, monthly subscriptions, and custom enterprise pricing

what is elevenlabs?

elevenlabs is an audio platform for text to speech, speech recognition, and voice agents. its elevenagents product handles customer conversations on your website or phone line, with voices, instructions, knowledge, and tools configured for each agent.

key features

• voice and language settings: configure language-specific voices and opening messages, with a language-detection tool for switching during the conversation.

• workflow subagents: change the instructions, tools, knowledge, model, or voice at selected stages of a visual workflow. each subagent handles its part of the conversation.

• backend and app actions: webhook tools call your apis, while client tools run functions you register in your app. use a client tool to open a support form or update part of the page during a browser conversation.

how does elevenlabs compare to vapi?

vapi already supports elevenlabs as a voice provider, so using its voices alone doesn't require a platform switch. elevenagents is the choice when you want to configure the voice, workflow, and agent tools through elevenlabs.

custom llms connect through compatible chat completions or responses endpoints. an existing vapi integration still needs its request, response, and tool formats mapped to the new agent. custom llms cannot be combined with the realtime-model configuration.

elevenlabs pricing

these are the regular monthly usd prices for elevenagents:

call hosting includes speech recognition and text to speech. llm usage is billed separately, and an external carrier bills its own phone charges. additional hosting minutes cost $0.08 per minute. prepaid top-ups are also available on self-serve accounts. enterprise pricing is custom.

optional burst calls cost $0.16 per hosting minute and receive lower-priority speech processing. burst capacity reaches up to three times the normal concurrency limit or 300 calls, whichever is lower for non-enterprise accounts.

standalone tts has its own usage pricing. the included agent minutes above are for conversations, not audio generation outside those calls.

when should you choose elevenlabs?

• you want voice and agent configuration together. manage your chosen voices, language-specific openings, and conversation workflows through elevenagents.

• your agent needs to work with your app's interface. register client tools that open a form, show a message, or change the page while the conversation continues.

bottom line

choose elevenlabs as your vapi alternative when your agent needs to speak and act inside your app. elevenagents brings language-specific voices, conversation workflows, and client tools into that setup.

which vapi alternative should you choose?

start with the requirement that changes your decision:

• rumik silk for natural, expressive voices with unlimited voice-agent minutes and text to speech at a fixed monthly price.

• retell ai for visual call flows and warm transfers that brief the person taking over.

• bland ai for bundled ai minute pricing and staged releases for agent updates.

• synthflow for enterprise phone operations that need visual call flows under an annual agreement.

• elevenlabs for agents built around elevenlabs voices that trigger actions inside your app.

is rumik silk right for you?

rumik silk is a vapi alternative i'd recommend if:

• you want a team that takes initiative. rumik is a small, hands-on team that makes your company's needs a priority, takes ownership of your questions, and works with you to get things moving.

• you want to hear your agent before putting it on a customer call. create an agent in the rumik playground and try your own greeting, customer questions, and interruptions.

• you want to try one workflow before moving everything. start with a receptionist or lead qualification agent, connect the backend tools it needs, and test the conversation before routing live calls to it.

start with the voice-agent guide to configure your first agent.