Terms of Use

If you use the Service on behalf of a company, organization, or other entity, you represent that you have authority to bind that entity, and “you” includes that entity. These Terms apply to consumer (B2C) and business (B2B) use, including use by software agents acting for you.

The Service is offered by Rainmaker LLC d/b/a LettersByLetter.com. Bruce Seymour is associated with the business; your contract is with Rainmaker LLC, not with any individual personally except as the law may otherwise require.

You must be at least 18 years old and have the legal capacity to enter a contract. You may not use the Service if you are barred from doing so under the laws of the United States or the jurisdiction from which you access it. If you use the Service for an organization, you must have authority to accept these Terms for that organization.

You are responsible for the accuracy of account information, for safeguarding passwords, session tokens, API keys, and other credentials, and for all activity that occurs under your account or keys — including activity by employees, contractors, and automated agents. Notify us promptly at hello@lettersbyletter.com if you believe credentials have been compromised.

We may refuse, suspend, or reclaim usernames, API keys, or accounts that we reasonably believe are abusive, misleading, or obtained without authorization. API keys are shown in full only once and are stored as hashes. You must treat keys as secrets.

LettersByLetter is a print-and-mail software service. You may compose text, upload documents (including PDFs), provide sender and recipient addresses, choose mail class and options, and authorize us to transmit those materials to third-party print-and-mail providers — currently LetterStream or successor vendors we designate — for printing, inserting, and delivery into the United States Postal Service (“USPS”) or other carriers those vendors use.

We operate as a software platform and intermediary. We do not ourselves print or carry mail. Once a job is released to a vendor or carrier, we do not control production queues, press schedules, induction into the mail stream, or delivery. USPS and vendor timelines are estimates only and are not guarantees.

The Service may run in demo or live mode. Demo mode simulates jobs and does not purchase postage or enter the USPS stream. Live mode is available only when we have enabled live fulfillment and valid vendor credentials. Pricing shown before a live vendor quote may be an estimate. A labeled demo environment is not a live mailing.

Features may include an address book, bulk CSV send, job status, a REST API, MCP tools, and prepaid credits. We may add, change, or discontinue features. We do not promise uninterrupted availability.

You retain ownership of documents, text, images, addresses, and other materials you submit (“User Content”). You grant Rainmaker LLC and its processors a worldwide, non-exclusive, royalty-free license to host, store, reproduce, format, transmit, print, and mail User Content, and to create operational copies, solely as needed to provide, secure, debug, and improve the Service, to prevent fraud and abuse, and to comply with law.

You represent and warrant that:

• you own User Content or have all rights, licenses, and consents needed to submit it and to authorize printing and mailing;
• User Content and the act of mailing it will not violate any law, regulation, court order, or third-party right, including privacy, publicity, and intellectual-property rights;
• addresses and recipient data are accurate to the best of your knowledge and were collected lawfully; and
• mailings you authorize are ones you are legally permitted to send.

We may refuse, delay, or cancel a job that we reasonably believe violates these Terms or the law, or that a vendor or carrier will not accept. Refusal does not create a duty to monitor content.

You may not use the Service to, or to attempt to:

• submit or mail unlawful, fraudulent, deceptive, defamatory, or threatening content;
• harass, stalk, intimidate, or abuse any person;
• infringe copyright, trademark, trade secret, patent, or other intellectual-property rights;
• send spam, unsolicited bulk mail, or mail that violates anti-spam, telemarketing, or consumer-protection laws;
• exploit, abuse, or endanger children, or create or distribute child sexual abuse material;
• threaten violence, promote terrorism, or solicit illegal weapons activity;
• impersonate any person or entity or misrepresent your affiliation;
• interfere with the Service, probe or breach security, or overload systems;
• resell the Service except under a written agreement with us; or
• use the Service in a way that would cause us or our vendors to violate law or carrier rules.

We may investigate suspected violations and cooperate with vendors, carriers, and authorities as described in Section 12.

Rainmaker LLC is not a law firm, accounting firm, or licensed professional practice. The Service, templates, documentation, status labels, and communications are tools for transmitting physical mail. They are not legal, tax, compliance, or other professional advice. You are solely responsible for deciding whether and how to mail something, for the wording of your documents, and for any legal effect of a mailing.

You are solely responsible for ensuring that each mailing and each use of recipient data complies with applicable law. That includes, without limitation, the Telephone Consumer Protection Act (TCPA) to the extent it applies to your campaign, the CAN-SPAM Act and similar commercial-message rules where they apply to mail or related electronic notices, state and federal mail and consumer-protection laws, privacy laws, industry regulations, and court or agency orders.

Providing the Service does not mean we have reviewed your content for legality or that a mailing is valid service of process, notice, or other legal delivery unless a statute or court expressly provides otherwise — and we make no such representation.

Prices for mail classes and options are posted on our pricing page and in the application. List prices may change. Live vendor quotes, postage, and surcharges may differ from estimates. Credits are a prepaid balance measured 1:1 with U.S. cents and may be used only for the Service. Credits are not legal tender, are not a bank deposit, and earn no interest.

We may accept card payments through payment processors and USDC payments via x402 facilitators. We do not custody crypto wallets or card numbers. Network fees, facilitator fees, and processor fees may apply and are your responsibility unless we expressly state otherwise.

Refunds. Demo-mode jobs do not purchase postage and are not billed as live mail. Once you authorize or submit a live mailing and production has begun — including transmission to LetterStream or another print-and-mail provider — that mailing is generally non-refundable, including postage, print, and vendor fees. Unused credits may be refundable only if required by law or if we agree in writing. Chargebacks and payment disputes initiated in bad faith may result in account suspension.

If a live job fails before release to a vendor because of our confirmed system error, we will restore the related credits or refund that job’s fees as your exclusive remedy for that failure.

The Service depends on third parties, including print-and-mail vendors (such as LetterStream), USPS and other carriers, cloud hosting, Firebase authentication and related Google services, payment processors and x402 facilitators, and analytics or session tools we may use. Those providers have their own terms and privacy policies. We are not liable for their acts, omissions, outages, delays, losses, or changes, except to the extent a non-waivable statute says otherwise.

Rainmaker LLC will comply with lawful requests from courts, law enforcement, regulators, and other authorities. When required by law — including a subpoena, court order, warrant, search warrant, civil investigative demand, national security process, or similar compulsory process — we may disclose customer information, account data, billing records, mailing records, documents you uploaded, recipient addresses, logs, and related data.

We may also disclose information when we reasonably believe disclosure is necessary to prevent imminent harm, to report suspected child exploitation or other serious crime, to protect the security of the Service, or to establish, exercise, or defend legal claims.

We may disclose without prior notice to you when notice is legally prohibited, would be impracticable, or would risk interfering with an investigation. Where legally permitted and consistent with the request, we may notify the affected customer.

We cooperate with lawful cybersecurity and government information-security requests, including requests associated with the U.S. Cybersecurity and Infrastructure Security Agency (CISA) and similar authorities, when we are legally required or reasonably believe cooperation is necessary to protect the Service, our users, or the public.

THE SERVICE IS PROVIDED “AS IS” AND “AS AVAILABLE.” TO THE MAXIMUM EXTENT PERMITTED BY APPLICABLE LAW, RAINMAKER LLC, ITS OFFICERS, DIRECTORS, MEMBERS, EMPLOYEES, AND AGENTS DISCLAIM ALL WARRANTIES, WHETHER EXPRESS, IMPLIED, STATUTORY, OR OTHERWISE, INCLUDING IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, TITLE, AND NON-INFRINGEMENT, AND ANY WARRANTIES ARISING FROM COURSE OF DEALING OR USAGE OF TRADE.

We do not warrant that the Service will be uninterrupted, timely, secure, or error-free; that mail will be delivered by any date; that tracking information is complete or accurate; or that defects will be corrected. You assume all risk arising from your use of the Service and from each mailing you authorize.

TO THE MAXIMUM EXTENT PERMITTED BY THE LAWS OF THE STATE OF CONNECTICUT AND THE UNITED STATES, RAINMAKER LLC AND ITS OFFICERS, DIRECTORS, MEMBERS, EMPLOYEES, AGENTS, AND SUPPLIERS WILL NOT BE LIABLE FOR ANY INDIRECT, INCIDENTAL, SPECIAL, CONSEQUENTIAL, EXEMPLARY, OR PUNITIVE DAMAGES, OR FOR ANY LOSS OF PROFITS, REVENUE, DATA, GOODWILL, OR BUSINESS INTERRUPTION, ARISING OUT OF OR RELATED TO THE SERVICE OR THESE TERMS, WHETHER BASED IN CONTRACT, TORT (INCLUDING NEGLIGENCE), STRICT LIABILITY, OR ANY OTHER THEORY, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.

OUR TOTAL LIABILITY FOR ALL CLAIMS ARISING OUT OF OR RELATED TO THE SERVICE OR THESE TERMS WILL NOT EXCEED THE GREATER OF (A) THE AMOUNTS YOU PAID TO RAINMAKER LLC FOR THE SERVICE IN THE TWELVE (12) MONTHS BEFORE THE CLAIM OR (B) ONE HUNDRED U.S. DOLLARS (US $100).

Some jurisdictions do not allow certain limitations. In those jurisdictions, our liability is limited to the fullest extent permitted by law. Nothing in these Terms limits liability that cannot be limited under applicable law, including liability for fraud or willful misconduct where such a limitation is prohibited.

You will defend, indemnify, and hold harmless Rainmaker LLC, Bruce Seymour, and their officers, directors, members, employees, contractors, and agents from and against any claims, damages, losses, liabilities, costs, and expenses (including reasonable attorneys’ fees) arising out of or related to: (a) your User Content; (b) mailings you submit or authorize; (c) your misuse of the Service; (d) your violation of these Terms or of law; (e) your violation of a third party’s rights, including intellectual-property, privacy, and publicity rights; or (f) use of your account or API keys by anyone you authorize or whose use you fail to prevent through reasonable care.

Before filing a claim, you agree to try to resolve the dispute informally by writing to hello@lettersbyletter.com and allowing thirty (30) days for a response, except where waiting would cause irreparable harm or a statute of limitations would expire.

These Terms are governed by the laws of the State of Connecticut, without regard to conflict-of-laws rules. Exclusive venue for any dispute that is not resolved informally lies in the state and federal courts located in New Haven County, Connecticut, and you consent to personal jurisdiction there.

Class action waiver. To the extent enforceable under applicable law, you and Rainmaker LLC waive any right to participate in a class, collective, consolidated, or representative action. Claims may be brought only in an individual capacity. If this waiver is found unenforceable as to a particular claim, that claim must be severed and the remainder of this section enforced.

You may stop using the Service at any time. We may suspend or terminate access immediately if you breach these Terms, if required by law or a vendor, if your use creates risk, or if we discontinue the Service. Upon termination, your license to use the Service ends. Sections that by their nature should survive — including ownership, licenses already exercised to complete mailings, payment obligations, disclaimers, limitations of liability, indemnification, legal process, dispute resolution, and this survival clause — will survive.

We may retain records as described in the Privacy Policy and as required for legal, tax, security, and fulfillment purposes.

We may update these Terms from time to time. The effective date at the top of this page will change when we do. Material changes will be posted on this page and, where appropriate, noted in the product or by email to the address on your account. Continued use after the effective date constitutes acceptance of the updated Terms. If you do not agree, you must stop using the Service.

These Terms were last updated and are effective as of September 9, 2026.

These Terms, together with the Privacy Policy and any order or pricing terms presented at checkout, are the entire agreement between you and Rainmaker LLC regarding the Service. They supersede prior or contemporaneous agreements on the same subject. If a provision is held unenforceable, it will be modified to the minimum extent necessary and the rest will remain in effect. Our failure to enforce a provision is not a waiver. You may not assign these Terms without our consent; we may assign them in connection with a merger, acquisition, corporate reorganization, or sale of assets. There are no third-party beneficiaries except the indemnified parties in Section 15. Headings are for convenience only.

The Service is controlled from the United States. We make no representation that it is appropriate or available in every location.

Questions about these Terms: