How to migrate from TextBolt to Sinch

TextBolt is an email-to-SMS gateway that lets US and Canadian businesses send texts by emailing a phone-number address from any mail client. Sinch is a cloud communications platform offering messaging, voice, and email APIs across roughly 150 countries. On the messaging.dev Score, TextBolt rates 17/100 and Sinch 92/100; this guide covers what that gap means in practice and how to re-point your sending code.

What changes when you move

Channels. With TextBolt you can send SMS only. Sinch keeps SMS and adds MMS, RCS, WhatsApp, Viber, Facebook Messenger, Telegram, Apple Messages for Business, voice, and email on the same account. You lose no channel by migrating in this direction.

Compliance. TextBolt lists no formal certifications. Sinch is aligned with GDPR, ISO 27001, SOC 2, and HIPAA.

Data residency. TextBolt runs on US servers only, with no region choice. Sinch offers US and EU servers plus APAC, Australia, and Brazil, and lets you choose where data is processed.

Pricing. TextBolt uses flat monthly subscriptions (Basic $29 through Enterprise) with a bundled segment allowance and per-segment overage, from $0.030/segment (Enterprise) to $0.058 (Basic). Sinch is pay-as-you-go (about $0.0075 per US segment plus carrier fees), with volume and committed-use options. New Sinch accounts include free trial credit; TextBolt offers no free developer credit.

Tooling. TextBolt ships no SDKs, has no sandbox, and its docs are rated low; the only integration path is SMTP. Sinch supports REST, SMTP, and SMPP, ships official SDKs for Java, Python, C#, Node.js, and PHP, provides a sandbox, and has high-quality docs. Both offer self-service onboarding. For a full walkthrough of the target, see how to start with Sinch; for a side-by-side, see the Sinch vs TextBolt comparison.

How the request format differs

TextBolt (source):

curl --ssl-reqd --url 'smtps://smtp.gmail.com:465' \
  --user '[email protected]:GMAIL_APP_PASSWORD' \
  --mail-from '[email protected]' \
  --mail-rcpt '[email protected]' \
  -T <(printf 'Subject: \r\n\r\nYour appointment is confirmed for tomorrow at 3 PM.\r\n')

Sinch (target):

curl -X POST 'https://us.sms.api.sinch.com/xms/v1/YOUR_SERVICE_PLAN_ID/batches' \
  -H 'Authorization: Bearer YOUR_API_TOKEN' \
  -H 'Content-Type: application/json' \
  -d '{"from":"+15005550006","to":["+15551234567"],"body":"Hello from Sinch"}'

Endpoint. TextBolt has no REST API: you connect to an SMTP server (smtps://smtp.gmail.com:465) and address the recipient as {E.164-without-plus}@sendemailtotext.com. Sinch is a REST POST to https://us.sms.api.sinch.com/xms/v1/{service_plan_id}/batches — note the us. host is region-specific.

Authentication. TextBolt has no API keys; you authenticate by sending from the email address registered and verified with your account (business/A2P 10DLC verification required), using your own mailbox’s SMTP credentials. Sinch uses a Bearer token in the Authorization header.

Payload mapping. The recipient moves from the --mail-rcpt address (E.164 without +, at sendemailtotext.com) to the to array (E.164 with +). The sender moves from --mail-from (your verified email) to the from field (a provisioned number or sender ID). The message body moves from the email body to the JSON body field.

Migration checklist

1. Create a Sinch account and generate an API token and service plan ID from the dashboard.
2. Provision a sender: Sinch’s from is a phone number or sender ID, not your email address.
3. Map fields: --mail-rcpt → to[], --mail-from → from, email body → body.
4. Re-point your sending code from the SMTP gateway to the REST endpoint matching your chosen data-residency region.
5. Re-test in Sinch’s sandbox before sending live traffic.
6. Update delivery callbacks: replace TextBolt’s email/Twilio-based status tracking with Sinch’s delivery-report webhooks.
7. Run both providers in parallel and reconcile delivery.
8. Cut over.

Watch out for

• Billing model. You move from a predictable flat monthly plan to pay-as-you-go per message plus carrier fees — model your volume before cutover.
• Secret management. You now hold a Bearer API token to rotate and protect; the email-only model had no keys.
• Region-specific endpoint. The quickstart uses the us. host — pick the base URL and service plan that match your residency region.
• Sender provisioning. You can no longer send “from” an ordinary mailbox; Sinch requires a valid number or registered sender ID.

Note: in this direction no channel, certification, or residency option is lost — the gotchas are operational, not feature regressions.