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ComparisoniMessage API4 min read

Free iMessage API

Flow gives your agent a free shared iMessage line for 25 people a month, plus a Telegram sandbox and simulated contacts. Start building without a phone.

By FlowPublished Updated

The short answer

Flow has a free iMessage line built for agents: a shared line for up to 25 people a month, plus a Telegram sandbox and simulated contacts, with the same code on every channel. When you grow, Flow's $30 shared line supports roughly 200 to 300 people 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.

Free tiers side by side

From each company's public pages as of October 2026.

Featureflow.engineerSendblueLinq
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 contactsSandbox: shared number, 10 verified contacts, inbound-first1Hobby plan: $0, 20 contacts2
Your agent can write first Yes, on a dedicated line with the outbound add-on, within warm-up limits. Otherwise customers text firstEnterprise plan only. The $100 AI Agent plan is inbound-first1Not stated on the pricing page; the CLI shows creating a chat to a number3
SMS and RCS SMS and RCS fallback from the same numberSMS, MMS and RCS on every line1RCS and SMS fallback2
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 limits$100 a month per dedicated line (AI Agent plan); outbound is custom1Pro from $260 a month; Enterprise custom2

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. Sendblue pricing
  2. Linq pricing
  3. Linq CLI page

Start free with Flow

Flow gives you a real path from first test to a live iMessage agent. Start with a free shared line for up to 25 people a month, or use a no-account Telegram sandbox and simulated contacts while you build the agent logic. The same handler then runs on Flow’s iMessage numbers.

The comparison table is there for visitors who arrived with a provider in mind. The important product decision is simpler: choose the platform that lets you build, test and grow without rewriting your agent.

When to upgrade

The free shared line is for a small pilot. When your agent reaches roughly 200 to 300 people a month, move to the $30 shared line. Dedicated lines start at $100 a month for teams that need their own number or a larger audience. Dedicated lines can support writing first subject to availability and warm-up limits.

Test an iMessage agent without a phone shows the developer workflow, and iMessage API pricing explains the plans.

How to use a free tier well

  1. Decide what you need to learn. Is it the API shape, the webhook flow, your agent’s logic or the phone experience? Pick the tier that tests that.
  2. Build the handler once. On Flow, the same code runs on the Telegram sandbox and on iMessage, so nothing is wasted.
  3. Test logic with simulated contacts, and the feel on a real phone. Simulation covers rules and edge cases. A real phone covers bubbles and typing.
  4. Read the limits. Contact caps, inbound-first rules and missing webhooks change what you can test.
  5. Plan the move to paid. Know the price shape before you build: per line, per message or per user.

When you are ready to build an agent, see Build an iMessage AI agent and Flow on iMessage.

Frequently asked questions

Is there a free iMessage API?

Yes. Flow has a free shared iMessage line for up to 25 people a month, a Telegram sandbox with no account required and simulated contacts for testing your agent without a phone.

Can I test iMessage on Flow for free?

Yes. Flow has a free shared iMessage line for up to 25 people a month, where customers text the line first. You can also test your agent's logic for free with a test key and simulated contacts, and chat with it on the Telegram sandbox.

Is there a free iMessage API that does not need a Mac?

Yes. Flow's free line and sandbox are hosted, so you do not need a Mac. Running your own relay is another route, but it needs a Mac you control.

Can I run a free iMessage API in production?

Flow's free shared line is for a small pilot of up to 25 people a month. For more people, the $30 shared line supports roughly 200 to 300 people a month.

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.ComparisonSendblue alternative: why teams choose FlowStart with Flow for free, scale from $30 a month, and run one agent across every channel.

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