Sincerely

Sincerely is B2B direct-mail software that turns CRM or CSV audiences into personalized postcards and letters, then compares campaign results with account-level holdouts. It fits revenue and marketing teams working from Salesforce or HubSpot that want sourced copy and address checks in the same workflow. The central appeal is controlled, measurable one-to-one mail; the main constraint is that live volume and advanced reporting depend on paid tiers.

Overview

Sincerely connects audience data, personalized print, approval, and measurement rather than acting as a simple mail-sending utility. Salesforce and HubSpot can supply account, contact, opportunity-stage, and campaign-membership data, while CSV import covers teams outside those systems. Every plan includes address verification and correction, with uncertain addresses sent to review, reducing the risk of spending a piece on a questionable destination.

Mail is currently limited to 4x6 and 6x9 postcards and letters. Handwritten notes and gifts cannot be fulfilled, so teams planning a broader physical-touch program need another provider for those formats. Lob prints US pieces and a Canadian provider prints Canadian pieces; customers do not contract with either vendor through Sincerely.

Key features

The writing system generates account-specific drafts from research and attaches each factual claim to a source. Human approval is required before anything prints, and edits are versioned. That combination makes generated copy auditable and preserves an editorial checkpoint, but it also means campaigns cannot run as an entirely automated print pipeline.

Account-level holdouts are included on every plan. Sincerely says five of eight campaign types measure lift against a holdout, while the Growth tier unlocks all eight types. This gives even smaller programs a control group, although the broadest measurement coverage is reserved for a substantially more expensive subscription.

Data is encrypted in transit, workspace access is scoped, and state-changing actions are recorded in an audit log. Sincerely says it neither sells personal information nor uses CRM data to train models or benefit another customer. MCP clients can connect through browser sign-in and OAuth, but agents cannot perform actions that print or spend; there is no API access.

When a plan reaches its monthly cap, live campaigns pause instead of printing extra pieces. That protects against unplanned overage, but teams with time-sensitive sends must monitor usage and choose enough headroom.

Pricing

The Audit plan is free (free) and includes CRM or CSV import, a mailability audit, brand kit and designs, and draft generation and editing. It cannot mail, so it is best for evaluating audiences, creative, and workflow before committing budget.

Pilot costs $199.00 USD once (billed one time) for 100 pieces, account-level holdout measurement, and no per-piece charges. The payment is credited toward the first month if you continue. It suits a bounded proof of concept, not recurring volume.

Core is $250 a month (billed $250/mo), with 150 pieces included and a ceiling of 600 per month, plus letters and postcards, Salesforce and HubSpot sync, and account-level holdouts. It is the entry point for live CRM-connected campaigns, but the included allowance is modest.

Starter is $500 a month (billed $500/mo) for 350 included pieces, up to 2,000 monthly, and standard reports. It fits teams scaling sends that do not yet need advanced attribution or governance.

Growth is $1,500 a month (billed $1,500/mo), including 1,300 pieces and up to 10,000 monthly. It adds all eight campaign types, approval workflows, spend limits, and opportunity attribution, making it the stronger choice for pipeline-linked programs with multiple reviewers.

Scale is $3,500 a month (billed $3,500/mo), with 3,700 included pieces and up to 25,000 monthly. Governance and roles, a named report contact, and the lowest per-piece prices target larger organizations that need administrative control and predictable support. There is no free trial.

Platforms

Sincerely runs on the web and supports Salesforce and HubSpot connections plus CSV import. Mail delivery covers both the United States and Canada through its printing partners.

Who it's for

Choose Sincerely if your team targets named accounts, already maintains usable CRM data, and needs sourced personalization, address review, approvals, and holdout-based measurement together. It is less suitable for handwritten or gift campaigns, API-first automation, or programs that need unrestricted volume without pausing at a cap.

Pros and cons

• Pros: one-to-one drafts cite their factual sources; human approval and versioned edits reduce copy risk; address correction and low-confidence review are included on every plan; account-level holdouts are universal.
• Cons: the free plan cannot mail; paid entry starts at $250 per month after the one-time Pilot; live formats exclude notes and gifts; no API access; monthly caps pause campaigns.

Alternatives

DocuPost is a better fit when a free web or API plan with no send limits is more important than Sincerely's account-level holdouts; its free tier charges per mailpiece and adds DocuPost branding to the cover letter.

Inkit suits teams centered on signature requests and storage, with web and API access and a free trial, rather than Sincerely's measured direct-mail workflow.

Lob Address Verification is the focused choice when address validation through an API matters more than campaign creation and attribution.

Postalytics fits readers seeking free campaign, template, and list limits with mail charged per piece.

PostPilot is an alternative for postcard programs that prefer a free starting tier and pay-as-you-go mail with analytics reports.

Stannp is worth considering for broad contact capacity and flexible send-volume terms on its free tier.

thanks.io is the alternative when pay-as-you-go mailing and full API access are priorities.

ZAP~POST is a better match for automation built around Zaps, integrations, webhooks, and logs.

See the Direct Mail Automation Software category for more options.

Verdict

Sincerely is best for CRM-led B2B teams that want personalized letters or postcards with sourced copy, mandatory approval, address safeguards, and holdout measurement in one web workflow. Choose it for that control and attribution; look elsewhere if you need an API, handwritten or gift fulfillment, or a low-cost way to mail at uncapped volume.