Sendblue review

Sendblue is a hosted messaging API with a SaaS sales interface. It sits between your application or CRM and phone-number-based messaging: your code sends requests to its REST API, and Sendblue handles iMessage delivery and fallback to RCS, then SMS, when iMessage is unavailable. It is not a messaging library you run as your own server.

For applications, that means Sendblue can provide a channel for agents, transactional conversations and sales follow-ups without building messaging transport yourself. Webhooks support two-way conversations, replies and delivery receipts. The wider product also includes a shared inbox, workflow builder, smart views and power dialer for sales teams. Sendblue says it does not support message blasts, citing their use for spam and harm to iMessage reputation. Its pricing separates an inbound-first AI Agent plan from Enterprise, which includes full outbound messaging.

The integration surface is a REST API, with Node.js and Python SDKs, cURL examples and a command-line tool. The vendor’s homepage shows a Node.js example that imports SendblueAPI from sendblue and sends a message with client.messages.send, passing message content and phone numbers. The CLI and SDK support are also listed for the free sandbox.

Sendblue describes webhooks and callbacks for inbound conversations and replies, alongside delivery receipts. Its homepage also describes CRM and automation connections and shows a HubSpot deal as an example workflow; confirm which connectors are available for your specific CRM. The homepage does not name SDK languages beyond Node.js and Python, so confirm SDK support in Sendblue’s docs before choosing another language. cURL is a documented integration surface in the vendor’s materials. The available information does not establish API rate limits or detailed SDK versioning; ask Sendblue about both before setting production retry and upgrade policies.

The Free Sandbox costs $0 per month and includes full API access, CLI and SDK support, community support and up to 10 verified contacts. Messaging is inbound-first, so this is for testing and development rather than unrestricted production use. The AI Agent plan costs $100 per dedicated line per month. It includes a dedicated number, inbound-first messaging, webhooks and callbacks, unlimited messaging per line, and up to 1,000 inbound contacts per day.

The listed production price is per line, not per seat or API request. Adding phone lines therefore raises the monthly bill, but Sendblue does not publish the price for additional lines. The pricing page lists Enterprise as custom-priced and includes full outbound messaging and multiple dedicated lines. The vendor does not publish annual billing prices. Its homepage says fallback to RCS and then SMS is available at no additional charge. Ask Sendblue how the daily contact limit is enforced, what happens when it is reached, and what Enterprise pricing includes before estimating a high-volume deployment.

Sendblue is presented as a hosted API and SaaS product. The vendor does not publish an open-source licence or a self-hosted deployment option, so plan to depend on Sendblue’s hosted service rather than operating the messaging stack yourself. The API and SDKs give your application a defined integration surface, but they do not remove the service dependency for number provisioning and message delivery.

The vendor does not publish a data-export process or a migration guide. Your application can keep its own records of conversations and delivery events, but ask Sendblue which message and contact data can be exported and in what format. Sendblue says it can port an existing phone number into its service, with setup requiring an additional 3–5 days; that is not the same as confirming how a number can be ported away. Before launch, get written answers on number ownership, conversation export and exit steps.

The production AI Agent plan includes up to 1,000 inbound contacts per day per line and says messaging is unlimited per line. The homepage also says Sendblue limits contacts messaged per day per phone line to prevent spam, and that additional lines can raise the limit. Those statements leave an operational question: confirm how the daily contact cap applies to your plan and what happens when traffic exceeds it. The vendor does not publish specific API rate limits.

Sendblue says its service has 99.9% uptime and sub-two-second average delivery; these are vendor claims, not independent measurements. It states that it is SOC 2 Type II certified and offers HIPAA-compliant plans. Ask for the relevant compliance documentation and service-level terms before handling regulated data. One Reddit user reports a free-plan rule requiring recipients to verify before an agent can message them, and says they paid to remove that restriction for groups. Treat that as a report to verify against current plan terms. Sendblue also says it does not support message blasts.