Guides & answers
DeepSeek API Error Codes Explained — Plus Two Failures DeepSeek Doesn't List
Short answer
- DeepSeek documents seven error codes — 400, 401, 402, 422, 429, 500, 503. Most fix themselves in minutes: 401 = wrong key, 402 = empty balance, 429 = slow down.
- The expensive failures are the ones that don't return an error at all: the retired names
deepseek-v4-flashanddeepseek-v4-flash-vision-expstill "work" but get silently served by a different model at a different price, anddeepseek-chat/deepseek-reasonerwere cut off on 24 July 2026. Verify what's actually serving you.
If your DeepSeek integration started failing this month, the cause is rarely exotic. DeepSeek's API returns a short, well-documented list of error codes, and most of them point at something you can fix in one line. The real traps sit outside that list: model names that quietly stopped meaning what they used to mean. This page walks the documented codes first, then the two undocumented failures we keep seeing — with sources and dates, as always.
The seven codes DeepSeek actually documents
| Code | What it means | The fix |
|---|---|---|
| 400 – Invalid Format | Malformed request body | Fix the body using the hints in the error message |
| 401 – Authentication Fails | Wrong API key | Check your key; create one if you don't have it |
| 402 – Insufficient Balance | Account out of funds | Check balance, top up |
| 422 – Invalid Parameters | A parameter value is invalid | Fix the parameter using the error hints |
| 429 – Rate Limit Reached | Requests too fast | Pace requests; see below |
| 500 – Server Error | Problem on DeepSeek's side | Retry briefly; contact support if it persists |
| 503 – Server Overloaded | Traffic spike | Retry after a wait |
Note the split between 400 and 422: 400 means the shape of your request body is broken (malformed JSON, wrong structure), while 422 means the shape was fine but a value wasn't. Same debugging reflex either way — read the error message, it names the field.
429: the error where DeepSeek tells you to go elsewhere
Rate-limit responses are usually a vendor telling you to wait. DeepSeek's docs go one step further:
"Please pace your requests reasonably. We also advise users to temporarily switch to the APIs of alternative LLM service providers, like OpenAI." — DeepSeek API docs, Error Codes page (read 14 September 2026)
That's unusually honest, and genuinely useful: most OpenAI-shaped tooling accepts a different base_url without code changes, so a second provider is a configuration line, not a rewrite. What the alternative costs against DeepSeek depends on your token mix — the cheapest-provider comparison keeps real monthly figures rather than rates that rot.
The failures that don't return an error
Here's what the error-code list can't tell you, because these fail silently:
Retired names that still work — at someone else's price. deepseek-v4-flash and deepseek-v4-flash-vision-exp are still accepted, but per DeepSeek's own docs the corresponding models have been retired: requests are served by DeepSeek-V4.1-Flash and billed at the Flash price. Your code keeps running, your logs keep saying 200 — but the model behind the response changed on a date you didn't choose. Our deployment guide covers the current name map and the reroute behavior in detail.
Names that were cut off entirely. The legacy pair deepseek-chat and deepseek-reasoner was announced for discontinuation on 24 July 2026 and is gone — requests using them now fail outright. If your integration predates July and started erroring this summer, this is the first thing to check: the fix is renaming the model, not debugging the request. deepseek-chat mapped to non-thinking mode, deepseek-reasoner to thinking — both live on in deepseek-flash, where thinking mode is on by default. That default is its own migration surprise: reasoning-heavy behavior arrives even when you didn't ask for it. The 3-minute SDK port guide walks the configuration side.
A five-minute triage order
- 401 — the key. Wrong, revoked, or from the wrong platform account.
- 402 — the balance. Top up, then check whether a runaway script is draining it.
- 400 / 422 — read the error hints; they name the broken field or value.
- The model string — if your code predates July, check it against the name map above before debugging anything else.
- What's actually serving you — after any 200, confirm the served model is the one you meant to pay for. Silent reroutes don't announce themselves.
Every claim on this page was checked against DeepSeek's live documentation on 14 September 2026. Error tables and model-name behavior can change without notice; treat the linked official pages as live truth, and this page gets a dated correction if they move.
Sources
- api-docs.deepseek.com — Error Codes page (read 14 September 2026), quoted verbatim for the 429 entry
- api-docs.deepseek.com — Your First API Call (current model names, retired-name routing, V4-Pro continuation note)
- api-docs.deepseek.com — Change Log entry of 24 April 2026 (announcement of the 24 July discontinuation)