Products

Flow FrameworkOpen-source, one codebase for every chat Unified APIiMessage, WhatsApp and Telegram Flow CloudHosting, tests and observability

Ships to

WhatsAppiMessageTelegramChatGPTClaudeMuseInstinctMCPCLI
PricingBlogDocs GitHub

ComparisoniMessage API5 min read

Flow vs Twilio: why Flow wins

Flow vs Twilio for iMessage: see why Flow is the better choice for AI agents, with a sourced feature table and plans side by side. Updated October 2026.

By FlowPublished Updated

The short answer

Flow gives your agent a US iMessage number, with SMS and RCS fallback, WhatsApp and Telegram from the same code, plus a hosted MCP server and CLI. Start free, then grow to a $30 shared line for roughly 200 to 300 people or dedicated lines from $100 a month.

Building on the iMessage API? Build on iMessage with Flow: one agent for iMessage, WhatsApp and Telegram. New to it? Read the iMessage API guide.

Flow and Twilio feature by feature

Flow first. Every cell links to the page it came from, and where we did not find something the table says to check with the provider.

Featureflow.engineerTwilio
Sends iMessage (blue bubbles) Yes. A US number, shared or dedicated, with blue-bubble repliesNot an iMessage channel in its docs. Its messaging docs cover SMS, RCS, WhatsApp and Messenger; Apple Messages for Business is a private beta1
WhatsApp and Telegram Both, through the same APIWhatsApp yes. Telegram not listed1
Webhook signing and retries HMAC-SHA256 signed; retried for 3 days; ordered per conversation; replayable event log2Requests signed with HMAC-SHA1 (X-Twilio-Signature)3
Free way to try it Free shared line: up to 25 people a month, customers text first. Plus a $30 shared line for roughly 200–300 people, a Telegram sandbox and simulated contactsTrial account (not for iMessage)
Price to start Free shared line up to 25 people a month; $30 shared line for roughly 200–300 people; dedicated lines from $100 a month; writing first subject to availability and warm-up limitsUS SMS from $0.0083 per segment, plus carrier fees and 10DLC fees4
Message limits Replies within 24 hours are not limited. Writing first is paced, and plans cap people a month (25 free, roughly 200–300 on the $30 shared plan)Priced per message

Last checked: October 2026. Prices and features change, so check each provider’s own pages before you rely on a detail. “Check with the provider” means we did not find it stated.

  1. Twilio Programmable Messaging docs
  2. Flow events and webhooks
  3. Twilio webhook security
  4. Twilio US SMS pricing

Why Flow

  • Blue bubbles. Flow gives your agent a real iMessage number.
  • Built for agents, not just numbers. One project answers on iMessage, WhatsApp and Telegram and serves as an MCP server and CLI, with hosting, tests and traces.
  • Pricing by line, not by message. A free shared line, a $30 a month shared line for roughly 200 to 300 people, and dedicated lines from $100 a month. A chatty agent costs the same.
  • Test without a phone. Simulated contacts let your test suite play the customer.

Put your agent on iMessage with Flow, free to start.

Build, test and scale in one place

Flow gives your team one messaging layer from the first sandbox test to a live iMessage line. The same agent, tools and delivery model work across iMessage, WhatsApp, Telegram and MCP, so new channels do not mean a new integration.

What to plan for

  • SMS or MMS in many countries, or voice: confirm the channel coverage you need before you choose a platform.
  • Server libraries: Flow ships TypeScript and Python and works over plain HTTP from any language.
  • Existing setup: Flow can add iMessage to an existing messaging stack without changing your agent tools.

Keep reading

For the whole market, read the best iMessage API and iMessage API pricing compared. To see how Flow works on iMessage, read Flow on iMessage: features, pricing and limits and Build an iMessage AI agent.

Frequently asked questions

Does Twilio support iMessage?

Flow gives your agent a US iMessage number with SMS and RCS fallback.

Can I use Flow and Twilio together?

Yes. Flow adds iMessage, WhatsApp and Telegram to your agent while your existing stack can continue handling the channels it already owns.

Which is cheaper, Flow or Twilio?

Flow starts with a free shared iMessage line, then a $30 shared line for roughly 200 to 300 people and dedicated lines from $100 a month, with no per-message pricing.

Does Twilio have an MCP server?

Flow hosts a messaging MCP server and builds MCP servers for your product.

Start hereiMessage API: a developer’s guideThe overview of how iMessage APIs work, and what to ask a provider. ComparisonDoes Twilio support iMessage?No. Flow gives your agent iMessage, and you can keep Twilio for SMS beside it.ComparisoniMessage API pricing comparedWhy Flow is the value pick: start free, support 200–300 people for $30 a month, and scale with dedicated lines from $100.ComparisonBest iMessage API for AI agentsWhy Flow is the best iMessage API for agents: one codebase, reliable webhooks, testing and every channel in one platform.ComparisonApple Messages for Business vs iMessage APITwo different things that both get called iMessage for business, side by side.ComparisonLinq alternative: why teams choose FlowWhy Flow is the best Linq alternative: a lower paid price, a free start and one agent on every channel.ComparisonFree iMessage APIStart free on Flow's shared iMessage line, test your agent without a phone, and scale to 200–300 people for $30 a month.

All posts: the Flow blog. The Flow docs have the reference.

From reading to building

Your agent, on iMessage and everywhere else.

Flow gives your agent an iMessage line, and the same code answers on WhatsApp and Telegram and works as an MCP server and CLI. See how it works on iMessage.

Build on iMessage with Flow