M365 Engineer

Jobtailor

Greater London

On-site

GBP 60,000 - 90,000

Full time

11 days ago

Application generator

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Job summary

Jobtailor is seeking an experienced Exchange Online and Microsoft 365 messaging specialist to lead mailbox migrations, configure mail-flow controls, and implement secure coexistence between messaging environments. The role emphasizes PowerShell automation, migration tooling, and strong documentation skills.

You will design, implement and validate mail routing, DNS/Autodiscover configurations, and drive pilot-to-production migrations with hands-on troubleshooting across Outlook and mobile

Qualifications

Extensive hands-on experience with Exchange Online and Microsoft 365 messaging.
Proven mailbox migrations within complex enterprise environments.
Experience with tenant-to-tenant and hybrid Exchange migrations at scale.
Strong understanding of Exchange Online architecture and administration.
Knowledge of DNS, Autodiscover and SMTP relay.
Experience managing mailbox permissions and distribution groups.
PowerShell automation for configuration, migration, validation and reporting.
Knowledge of Defender for Office 365, email security and compliance.
Experience supporting messaging migrations through pilot, production and cutover.
Excellent documentation and runbook creation skills.

Responsibilities

Configure and manage Exchange Online and Microsoft 365 messaging services according to approved architecture.
Design, implement and troubleshoot mail-routing configurations across environments.
Configure and manage connectors, domains, transport rules and mail-flow settings.
Establish secure coexistence between messaging environments and migrations across waves.
Develop migration plans, readiness checks and automation scripts.
Validate mailbox permissions, calendars, delegates and distribution groups.
Test and support Outlook/mobile access and client behavior.
Implement DNS changes and Autodiscover/SMTP relay configurations.
Provide early-life support and create runbooks and knowledge-transfer materials.

Skills

Exchange Online

Mailbox Migration

PowerShell

Microsoft 365

Mail Flow

DNS Management

Tenant-to-Tenant Migration

Hybrid Exchange

Security & Defender

Tools

Migration Tooling

Outlook/Desktop Clients

Migration Planning Tools

Job description

Configure and manage Exchange Online and Microsoft 365 messaging services according to approved architecture
Design, implement and troubleshoot mail-routing configurations across existing and target environments
Configure and manage connectors, accepted domains, transport rules, recipient settings and mail-flow controls
Establish and validate secure coexistence arrangements between messaging environments
Prepare and execute mailbox and messaging-object migrations across pilot and production waves
Develop migration plans and readiness checks
Validate mailbox permissions, delegates, shared mailboxes, calendars, distribution groups and messaging dependencies
Test and support mobile access and Outlook/client behaviour
Implement and validate DNS changes supporting messaging services
Configure and troubleshoot Autodiscover, SMTP relay and application mail-flow requirements
Implement email-security and compliance configurations
Support Defender for Office 365, anti-spam, anti-phishing and other messaging security controls
Assess migration readiness using scripts and tooling
Develop PowerShell automation for configuration, migration, validation, reporting and remediation
Produce migration reporting covering progress, success rates, failures, exceptions and outstanding actions
Monitor and troubleshoot mail-flow issues across internal and external systems
Investigate complex messaging, identity, DNS, client and application-integration issues
Support application and service teams with SMTP relay and messaging integrations
Diagnose authentication and identity-related messaging issues
Support cutover activities and service-continuity controls
Contribute to rollback and recovery planning
Provide early-life support after migration
Produce technical documentation, configuration records, runbooks and knowledge-transfer materials for operational handover

Requirements

Extensive hands‑on experience with Exchange Online and Microsoft 365 messaging
Proven experience delivering mailbox migrations within complex enterprise environments
Experience with tenant‑to‑tenant and/or hybrid Exchange migrations at scale
Strong understanding of Exchange Online architecture and administration
Strong knowledge of mail flow, connectors, accepted domains, transport rules and recipient configuration
Strong understanding of DNS, Autodiscover and SMTP relay
Experience managing mailbox permissions, delegates, shared mailboxes, calendars and distribution groups
Experience troubleshooting Outlook, mobile access and other messaging clients
Strong PowerShell and Exchange Online automation skills
Experience using scripting and migration tooling to assess readiness, execute changes and report progress
Good knowledge of email security, retention, compliance and Defender for Office 365
Experience supporting application‑to‑email integration and SMTP relay requirements
Strong troubleshooting capability across messaging, identity, DNS, client and application‑integration issues
Experience supporting messaging migrations through pilot, production, cutover and early‑life‑support phases
Strong testing and validation skills, with ability to produce clear test evidence
Good documentation skills, including technical runbooks, configuration records and operational handover documentation

Core Competencies

Demonstrates extensive hands‑on experience with Exchange Online and Microsoft 365 messaging, including mailbox migrations and complex enterprise environments. Proficient in PowerShell automation, email security, and troubleshooting across messaging systems.

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