{"uid":"cap_ae2w8fD1rlhyYClLrN0RY","slug":"free-small-biz-tools-late-fee-reminder-email-generator-c250f94c","name":"Free Small Biz Tools Late-Fee Reminder Email Generator","description":"Free Small Biz Tools API: Late-fee reminder email for an overdue invoice. Calculates the late fee and writes a ready-to-send reminder (subject + body) in a polite, firm or final tone. Bad input 400, never charged.","url":"https://api.freesmallbiztools.com/v1/late-fee-notice?utm_source=zero.xyz","method":"GET","headers":{},"bodySchema":{"type":"object","$schema":"https://json-schema.org/draft/2020-12/schema","required":["input"],"properties":{"input":{"type":"object","required":["type","method"],"properties":{"type":{"type":"string","const":"http"},"method":{"enum":["GET"],"type":"string"},"queryParams":{"type":"object","required":["amount","due_date"],"properties":{"rate":{"type":"string","description":"Rate number (default 1.5)"},"tone":{"enum":["polite","firm","final"],"type":"string"},"amount":{"type":"string","description":"Invoice amount, e.g. 1200"},"due_date":{"type":"string","description":"YYYY-MM-DD"},"paid_date":{"type":"string","description":"YYYY-MM-DD (default today)"},"rate_type":{"enum":["monthly_percent","annual_percent","daily_percent","flat"],"type":"string"},"grace_days":{"type":"string"},"client_name":{"type":"string"},"business_name":{"type":"string"},"invoice_number":{"type":"string"}}}},"additionalProperties":false},"output":{"type":"object","required":["type"],"properties":{"type":{"type":"string"},"example":{"type":"object"}}}}},"responseSchema":{"type":"json","example":{"kind":"late_fee_notice","tone":"polite","email":{"body":"Hi there, ...","subject":"Friendly reminder: your invoice was due 2026-09-01"}}},"example":null,"exampleRequest":null,"tags":["x402"],"displayCostAmount":"0.01","displayCostAsset":"USDC","priceDynamic":false,"priceHint":null,"priceStatus":"priced","priceSource":"probe","requiresHandshake":false,"reviewCount":0,"rating":{"score":"0.00","successRate":"0.00","reviews":0,"stars":null,"state":"unrated"},"availabilityStatus":"unknown","priceObserved":null,"sessionDeposit":null,"pricing":{"kind":"static","summary":"$0.01/call","primary":{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.01","per":"call","confidence":"exact"},"accepted":[{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.01","per":"call","confidence":"exact"}]},"paymentMethods":[{"uid":"pm_xrtoe4lRqOWLuRgbhXS0z","protocol":"x402","methodType":"crypto","chain":"base","mode":"charge","costAmount":"0.01","costPer":"request","priority":0,"asset":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","unit":"request","depositMicros":null,"planRef":null}],"brandName":null,"brandSlug":null,"brandBaseUrl":null,"brandDocsUrl":null,"whatItDoes":"Calculates the late fee on an overdue invoice and generates a ready-to-send reminder email (subject + body) in polite, firm, or final tone.","exampleAgentPrompt":"Draft a polite late-fee reminder email for my client Acme Corp — invoice #INV-2024 for $1,800 that was due on 2025-05-01, with a 1.5% monthly late fee and a 5-day grace period. My business name is Bloom Studio.","exampleUseCases":[{"title":"Freelancer chasing unpaid design invoice","prompt":"Write a firm late-fee reminder for my client Jordan Creative, invoice #FC-089 for $2,400 due on 2025-04-15. Use a 1.5% monthly rate with no grace days. My business is Studio Pixel."},{"title":"Final notice for long-overdue contractor payment","prompt":"Generate a final-notice late-fee email for Riverside Builds — invoice #RC-441 for $5,000 that was due on 2025-02-28. Charge a flat $150 late fee. My company is ProTech Services."},{"title":"Automated overdue billing for SaaS subscription","prompt":"Compose a polite overdue payment reminder for TechStart LLC, invoice #SUB-7712 for $350 due on 2025-05-10, applying a 15% annual late fee rate and a 3-day grace period. Business name is CloudBase Inc."}],"resultDescription":"Returns a JSON object with the notice kind, tone, and a ready-to-send email containing a subject line and full body text. The body includes the calculated late fee amount, days overdue, and a professional message tailored to the requested tone (polite, firm, or final).","failureModes":["400 Bad Request when required parameters (amount or due_date) are missing or malformed","400 returned for invalid date formats (must be YYYY-MM-DD)","400 returned for unsupported rate_type or tone enum values","Invalid numeric strings for amount or rate may trigger 400","No actual email is sent — the endpoint only generates the copy"],"whenToPreferThis":"Choose this endpoint when you need to automatically generate a professional, tone-calibrated late-fee reminder email without building the calculation or copy logic yourself. It is ideal for small business automation workflows, freelance billing agents, or any scenario where the agent needs to produce a human-ready overdue notice including a computed late fee in a single API call.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-10-15T06:30:21.870Z","isFirstParty":false,"canonicalSlug":"free-small-biz-tools-late-fee-reminder-email-generator-c250f94c"}