Libera.Date.Api is a high-precision date calculation engine designed to streamline business logic for global applications. Its core strength lies in its advanced Working Days System, which accurately calculates business days by automatically excluding weekends and public holidays for multiple countries (including 100 countries). Beyond simple duration checks, the API offers intelligent scheduling tools like finding the nearest available working day, analyzing date ranges for non-working intervals, and distinguishing between standard weekends and legal holidays. Whether you are computing SLAs, planning delivery windows, or building HR rosters, Libera.Date.Api ensures your dates align with real-world business calendars.

Accurate business-day, holiday, and scheduling math for major countries and their subdivisions — without maintaining a single holiday calendar yourself. Add or subtract working days, check if a date is a business day, find the next valid date, or count working days between two dates, with full support for regional subdivisions, custom weekends, and your own blackout dates. One simple GET call, instant JSON.

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Look up public holidays for 55 countries, calculate business day deadlines, find the next business day, export holidays to iCal, and more — all backed by versioned JSON data with no external dependencies at runtime. Covers 55 countries across Africa, Americas, Asia, Europe and Oceania for years 2024 to 2027.

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Pregnancy due date and gestational age API. EDD from LMP, conception, IVF transfer day, or ultrasound CRL. ACOG redating rules, trimester, and term milestones. Deterministic ISO 8601 dates.

Calculates business days, SLA due dates, holiday-aware deadlines, skipped weekends and holidays, business hours, and business-time durations.

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Due date from embryo transfer date. Day-3, day-5, day-6 and egg retrieval calculated separately.

Gestational age at any given date, returned as a 29w2d label and as total days.

Applies ACOG Committee Opinion 700 Table 1 to decide whether an ultrasound overrides LMP dating.

Ovulation estimate and 6-day fertile window from cycle length. Not contraceptive guidance.

Antenatal visit dates from the WHO 2016, NICE or ACOG published schedules, as calendar dates.

Due date from last menstrual period using Naegele's rule, with 21-45 day cycle length correction.

Trimester boundaries, 24w0d viability, and four preterm and four term classes with their dates.

Dating from BPD, HC, AC and FL measurements in millimetres, using Hadlock 1984 equations.

Conception date from a last menstrual period or from a known due date, as ISO 8601 dates

Calculate business days accurately while accessing global holiday data to optimize your workflows.

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Unified access to 22 official US government datasets: business registries, building permits, OFAC sanctions, SEC filings, and more. 20M+ records.