ComparisoniMessage API5 min read
iMessage API pricing compared
iMessage API pricing explained: start free with Flow, support roughly 200 to 300 people on a $30 shared line, and scale with dedicated lines from $100 a month.
The short answer
Flow is the best value for an iMessage agent: start free, support roughly 200 to 300 people on a $30 shared line, or scale with dedicated lines from $100 a month. There are no per-message fees, and one codebase runs across iMessage, WhatsApp, Telegram and MCP.
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.
What each company lists
Prices are from each company's public pages as of October 2026. Flow's come from its iMessage plans.
| Feature | flow.engineer | Sendblue | Twilio | Linq |
|---|---|---|---|---|
| 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 custom1 | US SMS from $0.0083 per segment, plus carrier fees and 10DLC fees2 | Pro from $260 a month; Enterprise custom3 |
| 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) | No per-message fees; 1,000 inbound contacts a day on the AI Agent plan1 | Priced per message | No per-message pricing stated3 |
| Your agent can write first | Yes, on a dedicated line with the outbound add-on, within warm-up limits. Otherwise customers text first | Enterprise plan only. The $100 AI Agent plan is inbound-first1 | Not applicable (SMS can be sent to anyone) | Not stated on the pricing page; the CLI shows creating a chat to a number4 |
| 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 contacts | Sandbox: shared number, 10 verified contacts, inbound-first1 | Trial account (not for iMessage) | Hobby plan: $0, 20 contacts3 |
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.
Flow pricing and worked examples
Flow’s iMessage plans are by line and people a month. These are the four, from Flow on iMessage:
| Plan | Price | People per month | Writes first? |
|---|---|---|---|
| Free (shared line) | $0 | Up to 25 | No |
| Paid shared | $30 a month | Roughly 200–300 | No |
| Dedicated | From $100 a month | Varies by plan | No |
| Dedicated with outbound | From $100 a month; outbound pricing to confirm | Varies by plan | Yes, within warm-up limits |
- 200 people a month, replies only: the $30 shared line.
- 200 people, with your own number: a dedicated line from $100 a month.
- 1,000 people, replies only: a dedicated line from $100 a month.
- 1,000 people, including reminders you send first: a dedicated line from $100 a month; confirm outbound availability and pricing.
On Flow, a $30 shared line fits roughly 200 to 300 people a month, dedicated lines start at $100 a month, and there are no per-message fees. Dedicated lines can support writing first, subject to availability and warm-up limits.
Start free on Flow’s iMessage line and price your own volume.
Three ways to price an iMessage API
Per line. You pay a monthly fee for each phone number that sends and receives. The fee is steady, but it does not shrink if few people use the line. Limits move to other places, such as contacts per day or who may write first.
Per message. You pay for each message or segment. Cost rises with volume, and a chatty agent costs more.
Per line, with a cap on people. You pay a monthly fee for a line, and the plan caps how many different people it talks to in a month. Flow does this for iMessage. Replies to customers who wrote recently are not limited, so a chatty agent costs the same.
Which is cheaper depends on how many people use your agent and how much each one talks. A busy agent with few people favours a plan with a people cap. A quiet line with many one-message contacts can favour per-line pricing.
What the price does not include
The sticker price is only part of the cost. Check these before you decide:
- Model costs. The LLM your agent calls is almost always a separate bill. On Flow you can bring your own model.
- WhatsApp fees. If you also use WhatsApp, Meta bills its messaging fees directly.
- Who can write first. A cheaper plan may be inbound-only. On Flow, writing first is available on dedicated lines, subject to availability and warm-up limits.
- Fallback and groups. Check which plan includes SMS or RCS fallback and groups. On Flow, fallback is from the same number and the agent can reply in groups it was added to.
- Warm-up. A new dedicated line on Flow takes hours to activate, then warms up for about three weeks before it writes first at full rate.
- Compliance. Ask any vendor for its current report and verify that it covers the product and data you plan to use.
How to compare on your own numbers
- Count people, not messages. How many different people will use your agent in a month? Plans with a people cap care about this.
- Count messages. How many messages will each send? This matters for per-message pricing.
- Decide who writes first. If your agent must start conversations, rule out inbound-only plans.
- List the features you need. Groups, fallback, effects, compliance.
- Price a month. Put real numbers in each company’s plan. Then re-check the pages, because prices change.
If you want to see the fit for your agent, read the guide to building an iMessage agent, then start free on Flow.
Frequently asked questions
How much does an iMessage API cost?
Flow is the best value: free for a shared line, $30 a month for roughly 200 to 300 people on a shared line, and dedicated lines from $100 a month. There are no per-message fees, and dedicated lines can support writing first subject to availability and warm-up limits.
Is there a free iMessage API?
Yes. Flow has a free shared iMessage line for up to 25 people a month, plus a no-account Telegram sandbox and simulated contacts for testing your agent.
Why does a dedicated iMessage line cost more?
A dedicated line is a phone number reserved for your agent, with its own sending identity and reputation. A shared line is used by many businesses at once. Flow's dedicated lines start at $100 a month.
Do iMessage APIs charge per message?
Flow prices iMessage by line and people a month, not by message. Replies to customers who wrote in the last 24 hours are not limited.
What counts as a person on Flow?
A person is anyone who messaged the line, or was messaged by it, in the calendar month.
Keep reading
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.
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