Comall Agency

Validate GS1 check digits for EAN-13, EAN-8 and UPC-A barcodes in bulk, or compute the missing digit for a code sent one digit short. The mode is picked per code, so mixed batches work in one run. Pure algorithm: no product database, no third-party API, no signup.

Check card numbers against the Luhn checksum and detect the network (Visa, Mastercard, Amex, Discover, Diners, JCB) from the prefix. 100% offline: the number stays in memory and never reaches the output or the logs, only a masked form. Checksum only, not an authorization.

Validate standard 5-field cron expressions, get a plain-English description of each schedule, and compute the next run times in UTC (1 to 20 per expression). Supports *, lists, ranges and steps. An invalid expression is reported in its own row, not as a batch error.

Clean an email list before a campaign or a CRM import: syntax, a live MX lookup, disposable-domain matching, role-account detection and typo suggestions such as gmial.com to gmail.com. No signup and no third-party API. No SMTP handshake, so mailbox existence is never claimed.

Confirm an EU VAT number against the European Commission's own VIES service, after a per-country format check. Returns the registered name and address when the member state publishes them. Never charged when VIES is unreachable: that verdict means try again later, not invalid.

Validate a Factur-X invoice (PDF/A-3 or bare CII XML) against EN16931 and the French BR-FR business rules, or generate a compliant PDF/A-3 from invoice data. Totals are recalculated server-side and a mismatch is rejected, never silently corrected. Preflight for the 2026 mandate.

Resolve a French business partner from a SIRET, SIREN or intra-EU VAT number, for the party blocks of a Factur-X invoice ahead of the 2026 e-invoicing mandate. Returns official identifiers and address from public registries, with the VAT state reported explicitly rather than guessed.

Validate IBANs fully offline: country length from the ISO 13616 registry (78 countries), mod-97 checksum, BBAN extraction and clean 4-character formatting. The verdict says why a value failed, and expected_length beside actual_length makes a bad paste obvious. No bank lookup.

Score passwords in bulk on entropy, character classes, a list of 56 of the most common breached passwords, keyboard sequences and repeated characters, with readable feedback explaining each score. 100% offline, no breach-database lookup, and the password itself is never returned in the output.

Check whether a username exists on GitHub, GitLab, Docker Hub, Keybase and Hacker News in a single call, through each platform's own public API. No login and no scraping. A platform that times out is reported as unknown, never collapsed into not-found.