Reading inbound EDI (999 / 277CA / 277 / 835)
Step 1 — Inbound files are parsed and applied automatically
You don't open or work an inbox. As each inbound file lands from the clearinghouse, the worker parses it, matches it to a bill, and records the outcome on that bill's history timeline — e.g. a 999 'AK9*A — syntax accepted' moving bills to Sent, or a 277CA '87 STC*A1 (accepted) · 1 STC*R0 (rejected — claim number missing).' Status changes flow into your Tasks queue, so you act on results rather than reading raw X12.
Step 2 — Understand the acknowledgment sequence
The inbound types arrive in order and each moves the bill forward. The 999 functional acknowledgment confirms the clearinghouse received a syntactically valid file (AK9*A = accepted). The 277CA is the payer's claim-level acknowledgment — STC*A1 accepts the claim into adjudication, STC*R0 rejects it (with the reason, like a missing claim number). The 277 reports mid-cycle status. Each is matched to its bill and appended to the bill's timeline.
Step 3 — The 835 ERA is where payment posts
The 835 electronic remittance advice is where money actually posts. Mindbill decodes the CAS adjustment codes on each 835 and posts the payment to the matching bill, computing the variance against the Medical-Legal Fee Schedule. When it spots an illegal PPO/MPN reduction (PR-242 on a med-legal bill), it flags the short-pay and queues the Second Review playbook instead of letting it pass as 'paid.' An 835 that doesn't match any bill is captured as an unmatched payment in Reconciliation rather than dropped.
Step 4 — Parse errors and the acknowledgment trail
Not every file parses cleanly — a clearinghouse can send a malformed segment. Files that fail to parse are logged for follow-up rather than silently discarded, and the underlying file bytes are retained. Because every parsed transaction is timestamped and matched to its bill, the bill timeline doubles as your acknowledgment trail — proof of exactly when each ack and remittance arrived if a payer later disputes timing.
After a bill goes out as an 837P, the payer and clearinghouse answer in a fixed sequence of X12 transactions. Mindbill's inbound EDI worker parses each file, demuxes it by submitter ID, matches it to the right bill, and advances the bill's status automatically — no manual X12 reading required. This article explains the acknowledgment sequence and where the results show up. (There is no separate inbox screen to monitor: posted and unmatched 835 payments surface in Reconciliation, and each ack/remittance is recorded on the bill's own timeline.)