DeepSeek Error Codes: What They Mean and How to Fix 400, 401, 402, 422, 429, 500, and 503

Last verified: July 11, 2026

DeepSeek Error Codes tell you whether an API request failed because of your request format, API key, account balance, parameters, request pacing, or a DeepSeek-side server problem. The fastest way to debug them is to separate fix-first errors from retry-first errors.

For the official DeepSeek API, the documented error codes are:

  • 400 — Invalid Format
  • 401 — Authentication Fails
  • 402 — Insufficient Balance
  • 422 — Invalid Parameters
  • 429 — Rate Limit Reached
  • 500 — Server Error
  • 503 — Server Overloaded

DeepSeek’s error-code documentation lists these seven codes with their causes and suggested solutions.

This guide summarizes official DeepSeek API documentation together with practical debugging patterns for production applications. Because the DeepSeek API evolves over time, always verify the latest official documentation before deploying production changes.

Quick Answer: Should You Fix the Request or Retry?

Error codeOfficial meaningMost likely causeFirst thing to doRetry?
400Invalid FormatInvalid JSON or request body formatValidate the request body and compare it with the API docsNo, fix the request first
401Authentication FailsWrong, missing, revoked, or misconfigured API keyCheck the Authorization: Bearer header and the API key sourceNo, fix credentials first
402Insufficient BalanceAccount balance has run outCheck billing and top up if neededNo, retry only after balance is available
422Invalid ParametersUnsupported or invalid request parameterRead the error message and fix the parameter/model/body fieldNo, fix parameters first
429Rate Limit ReachedRequests are being sent too quickly or concurrency is exceededReduce concurrency, queue requests, and use backoffYes, after slowing down
500Server ErrorDeepSeek server encountered an issueRetry after a short delay; contact support if persistentYes, with controlled backoff
503Server OverloadedHigh traffic or temporary overloadWait and retry; consider fallback routingYes, with controlled backoff

The key rule is simple: do not blindly retry 400, 401, 402, or 422. Those usually require a local fix. Use controlled retries for 429, 500, and 503, but avoid retry storms.

Before Troubleshooting: Confirm Which API Format You Are Using

DeepSeek supports API formats compatible with OpenAI and Anthropic. The official first-call documentation lists the OpenAI-format base URL as https://api.deepseek.com and the Anthropic-format base URL as https://api.deepseek.com/anthropic. It also lists current model IDs such as deepseek-v4-flash and deepseek-v4-pro; deepseek-chat and deepseek-reasoner are scheduled for deprecation on July 24, 2026 at 15:59 UTC.

Before you investigate the error code, check these basics:

  1. Are you calling the right base URL for your client?
  2. Are you sending the request to /chat/completions for OpenAI-compatible chat completions?
  3. Are you using a currently supported model ID?
  4. Is the request body valid JSON?
  5. Is the API key being passed as a Bearer token?
  6. Are you using the direct DeepSeek API, or a third-party gateway, SDK wrapper, proxy, or agent tool?

That last point matters. A wrapper may convert DeepSeek’s response into its own error format. When possible, reproduce the error with a direct curl request before debugging the rest of your stack.

Minimal Known-Good Request to Compare Against

Use a small request to confirm whether the API key, base URL, model ID, and JSON body are basically correct.

curl https://api.deepseek.com/chat/completions \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer ${DEEPSEEK_API_KEY}" \
  -d '{
    "model": "deepseek-v4-flash",
    "messages": [
      {
        "role": "user",
        "content": "Return the word OK."
      }
    ],
    "stream": false
  }'

The API reference says POST /chat/completions creates a model response for a chat conversation, and it marks messages and model as required body fields. The same reference lists deepseek-v4-flash and deepseek-v4-pro as possible model values.

If this minimal request works, your API key and basic connection are probably fine. Compare your failing request against it and look for extra parameters, malformed message objects, unsupported model names, bad JSON, or wrapper-specific settings.

400 — Invalid Format

A DeepSeek 400 Invalid Format means the request body format is invalid. The official fix is to modify the request body according to the hints in the error message and the API docs.

Common causes

  • Broken JSON syntax.
  • Missing required fields such as model or messages.
  • messages is not an array.
  • A message object is missing role or content.
  • Content-Type: application/json is missing or wrong.
  • The request body is being double-encoded as a string.
  • A proxy or SDK wrapper is changing the payload before it reaches DeepSeek.

Fastest fix

Log the outgoing request body without secrets, then validate it as JSON. Compare it with a minimal known-good request.

Do not log:

Authorization: Bearer sk-...

Log safer debugging fields instead:

{
  "url": "https://api.deepseek.com/chat/completions",
  "method": "POST",
  "model": "deepseek-v4-flash",
  "message_count": 1,
  "stream": false,
  "has_authorization_header": true
}

Should you retry?

No. Retrying the same malformed request will usually return the same 400. Fix the request format first.

401 — Authentication Fails

A DeepSeek 401 Authentication Fails means authentication failed because of the wrong API key, According to the DeepSeek error-code documentation DeepSeek’s API reference states that authentication uses HTTP Bearer Auth, and the first-call documentation shows the API key being sent in the Authorization: Bearer ${DEEPSEEK_API_KEY} header.

Common causes

  • The API key is missing.
  • The environment variable is empty in production.
  • The header is formatted incorrectly.
  • You copied an API key with whitespace or hidden characters.
  • You are using a key from another account, region, workspace, or environment.
  • The key was deleted, rotated, or revoked.
  • Your serverless environment did not receive the secret at runtime.
  • A frontend app is calling the API directly instead of using a backend service.

Fastest fix

Check the exact runtime value source, not only your local .env file.

For example, confirm these conditions:

DEEPSEEK_API_KEY exists: yes
Authorization header present: yes
Header format: Bearer <redacted>
Request made from backend: yes

Never expose a real DeepSeek API key in browser code, logs, screenshots, GitHub issues, or client-side error reports.

Should you retry?

No. A 401 is not a temporary server overload. Retrying will not help until the key or header is fixed.

402 — Insufficient Balance

A DeepSeek 402 Insufficient Balance means the account has run out of balance. The official error-code page instructs users to check their account balance and top up.

DeepSeek’s pricing page says API fees are deducted from topped-up balance or granted balance, and it recommends checking the pricing page for the most recent pricing information because prices may vary.

Common causes

  • The account balance is empty.
  • A payment or top-up was made on a different account.
  • Granted balance was used before topped-up balance.
  • A production job consumed more tokens than expected.
  • You are checking usage by the wrong API key or account.

Fastest fix

Go to the DeepSeek platform billing area and confirm:

  1. The logged-in account is the same account used by the API key.
  2. The account has available balance.
  3. The production workload has not unexpectedly increased token usage.
  4. The failing environment is not using an old key from a different account.

DeepSeek’s FAQ says users can top up online and check billing, and it also explains that detailed usage by API key can be exported from the Usage page.

Should you retry?

No. Retrying without balance will continue to fail. Retry only after the account has usable balance.

422 — Invalid Parameters

A DeepSeek 422 Invalid Parameters means the request contains invalid parameters. The official solution is to modify the request parameters according to the hints in the error message and the API format documentation.

This is different from 400, but the distinction is not always absolute. Depending on how the request is parsed, similar issues may result in either 400 Invalid Format or 422 Invalid Parameters. In general, 400 usually points to request formatting problems, while 422 usually indicates that the request is syntactically valid but contains unsupported or invalid values.

Common causes

  • Unsupported model ID.
  • Parameter value outside the accepted range.
  • Passing a parameter that your selected endpoint does not support.
  • Using a deprecated or compatibility model name after its supported period.
  • Incorrect response_format.
  • Invalid tools, tool_choice, or function schema.
  • Passing stream_options when stream is not enabled.
  • Invalid user_id format.

The chat completions reference lists several parameter constraints, including supported model values, thinking.type values, reasoning_effort values, stream_options usage, and user_id character/length rules.

Fastest fix

Read the exact error body and identify the field name. Then remove optional fields until the request works.

A practical debugging sequence:

  1. Start with only model, messages, and stream.
  2. Add thinking or reasoning_effort only after the base call succeeds.
  3. Add JSON mode, tools, user_id, or streaming options one by one.
  4. If the error returns after adding a field, that field is the likely cause.

Should you retry?

No. A 422 means your parameters need to change. Retrying the same body wastes requests and makes logs noisier.

429 — Rate Limit Reached

A DeepSeek 429 Rate Limit Reached means you are sending requests too quickly. DeepSeek’s official error-code page recommends pacing requests reasonably and says users may temporarily switch to alternative LLM service providers.

DeepSeek’s rate-limit documentation is especially important here. As of July 10, 2026, the official page documents account-level concurrency limits: 500 for deepseek-v4-pro and 2500 for deepseek-v4-flash. It also says a request counts as concurrent from the time it is sent until the response is complete, concurrency is calculated at the account level regardless of which API key is used, and exceeding the limit results in HTTP 429.

Common causes

  • Too many simultaneous requests.
  • No queue in front of the API.
  • Multiple workers, cron jobs, or services sharing one account.
  • Long-running responses increasing active concurrency.
  • Streaming or slow completions keeping connections open.
  • A retry loop that sends more traffic after receiving 429.
  • Assuming each API key has a separate concurrency pool.

Fastest fix

Reduce active concurrency before increasing retries.

A safe approach:

  1. Add a queue.
  2. Set a maximum number of in-flight requests.
  3. Use exponential backoff with jitter for retryable errors.
  4. Track 429 rate separately from other failures.
  5. Avoid retrying all failed requests at the same time.
  6. Consider a fallback provider only for workloads that can tolerate model differences.

Example retry pattern

This is an implementation pattern, not a quoted DeepSeek requirement:

import random
import time

RETRYABLE_STATUS_CODES = {429, 500, 503}

def sleep_before_retry(attempt: int) -> None:
    base_delay = min(2 ** attempt, 30)
    jitter = random.uniform(0, 1)
    time.sleep(base_delay + jitter)

def should_retry(status_code: int) -> bool:
    return status_code in RETRYABLE_STATUS_CODES

For 429, backoff alone is not enough if your active concurrency remains too high. You need to slow the intake rate or reduce in-flight requests.

Should you retry?

Yes, but only after slowing down. Immediate retries can make the problem worse.

500 — Server Error

A DeepSeek 500 Server Error means DeepSeek’s server encountered an issue. The official recommendation is to retry after a brief wait and contact DeepSeek if the issue persists.

Common causes

  • Temporary provider-side issue.
  • Internal failure during request processing.
  • Brief instability in a model-serving path.
  • Rare edge case triggered by a valid request.

Fastest fix

First, confirm the request is not obviously invalid. If the same request sometimes succeeds and sometimes returns 500, treat it as retryable. If every request fails, check the DeepSeek status page and your own network path.

During an incident, check the official DeepSeek Status page and compare the API Service status with the Web Chat Service status. API availability and web chat availability can differ, so always verify the current system status before assuming the problem is in your application.

Should you retry?

Yes, with controlled backoff. Do not retry indefinitely. After a few failed attempts, surface a clear error to the user and keep the request available for later replay if your product supports it.

503 — Server Overloaded

A DeepSeek 503 Server Overloaded means the server is overloaded because of high traffic. The official solution is to retry after a brief wait.

Common causes

  • Temporary high traffic.
  • Provider-side capacity pressure.
  • Request scheduling delays.
  • A workload spike from your own application combined with provider load.

Fastest fix

Pause and retry with jitter. If your application is user-facing, show a friendly temporary message instead of making the user wait silently.

Example user-facing message:

DeepSeek is temporarily busy. Please try again in a moment.

For backend jobs, queue the request and retry later. For real-time applications, consider a fallback model only if the task does not require exact output consistency.

Should you retry?

Yes. A 503 is one of the clearest retryable DeepSeek error codes, but retries should be paced.

429 vs 503: What Is the Difference?

429 usually means your account or application is sending requests too quickly. DeepSeek’s rate-limit page says exceeding account-level concurrency limits returns HTTP 429.

503 means DeepSeek’s servers are overloaded due to high traffic, according to the official error-code page.

SituationMore likely codeWhat to do
Your workers send too many simultaneous requests429Reduce concurrency and queue requests
All customers hit failures during a provider traffic spike503Retry later and check status
Only one tenant or job causes failures429Add per-tenant throttling
A simple request fails during a known service incident503 or 500Backoff and monitor
Every retry happens immediatelyMore 429/503Add jitter and retry limits

DeepSeek API Feels Slow or Returns Empty Lines

Not every strange response is an error code. DeepSeek’s rate-limit documentation says that while a request is waiting, non-streaming requests may continuously return empty lines, and streaming requests may return SSE keep-alive comments such as : keep-alive. It also says these do not affect JSON parsing, but custom HTTP parsers should handle them correctly.

The official FAQ gives the same explanation and notes that non-streaming output returns only after generation is complete, while streaming output improves interactivity.

Practical fixes:

  • Use stream: true for interactive user interfaces.
  • Make sure your HTTP client does not treat keep-alive lines as invalid JSON.
  • Increase read timeouts carefully for long generations.
  • Track time spent waiting for the first token separately from total completion time.
  • Do not classify keep-alive lines as 500 or 503 unless the final HTTP response actually contains that status code.

Safe Logging Checklist for DeepSeek Troubleshooting

Good logs make DeepSeek troubleshooting faster. Unsafe logs leak secrets.

Log these:

  • HTTP status code.
  • Endpoint path.
  • Model ID.
  • Request ID from your own system.
  • Message count.
  • Token estimate if available.
  • Whether streaming was enabled.
  • Retry attempt number.
  • Sanitized error message.
  • Queue wait time.
  • In-flight request count.

Do not log these:

  • Full API key.
  • Full Authorization header.
  • Sensitive user prompts.
  • Private customer data.
  • Raw files or attachments.
  • Full billing information.
  • Secrets from environment variables.

For privacy-sensitive systems, log metadata by default and store full payloads only in a controlled, short-retention debug mode.

Retry vs Fix Decision Table

CodeCategoryRetry strategyPrevention
400Request formatDo not retry unchangedValidate JSON before sending
401AuthenticationDo not retry unchangedCentralize secret management and rotate carefully
402Billing/accountDo not retry until balance is fixedMonitor balance and usage
422ParametersDo not retry unchangedValidate model IDs and parameter ranges
429Rate/concurrencyRetry with backoff after reducing pressureQueue requests and cap concurrency
500Server-sideRetry briefly with backoffAdd retry limits and incident monitoring
503OverloadRetry after delay with jitterAdd fallback behavior for non-critical traffic

Production Strategy for Fewer DeepSeek API Errors

1. Validate before sending

Catch 400 and 422 before they reach DeepSeek whenever possible.

Validate:

  • model
  • messages
  • response_format
  • stream
  • stream_options
  • tools
  • tool_choice
  • user_id
  • JSON syntax
  • required fields

DeepSeek’s chat completion reference provides the current parameter rules and accepted values for many of these fields.

2. Separate retryable and non-retryable errors

A common production mistake is to retry all errors the same way. That makes 400, 401, 402, and 422 more expensive without fixing them.

Use a simple classification:

Fix first: 400, 401, 402, 422
Retry carefully: 429, 500, 503
Investigate separately: timeouts, network errors, SDK wrapper errors

3. Add concurrency control

Because DeepSeek’s current public documentation describes account-level concurrency behavior, production systems should use a queue or worker pool instead of allowing unlimited simultaneous requests.

Useful metrics:

  • Current in-flight DeepSeek requests.
  • Queue length.
  • Average request duration.
  • 429 rate by service and tenant.
  • Retry count by status code.
  • Time to first token for streaming requests.
  • Total response duration.

4. Use jitter, not synchronized retries

If 1,000 jobs all retry exactly five seconds later, you can create a second traffic spike. Add random jitter to spread retries across time.

5. Set a retry budget

A practical retry budget might be:

  • 429: retry a few times with increasing delay, then queue or fail gracefully.
  • 500: retry briefly, then surface an incident-friendly message.
  • 503: retry after a slightly longer delay, then use fallback if appropriate.

Do not hide long failures from users. A clear temporary error is better than a spinner that never ends.

6. Monitor balance before users notice

For 402, alert before the account reaches zero. Track daily token usage and unexpected spikes. DeepSeek’s FAQ notes that usage data can be exported by API key, which can help identify the key or workload responsible for spend.

Troubleshooting Checklist

Use this checklist when you see a DeepSeek API error and need a fast diagnosis.

Request and endpoint

  • Am I using https://api.deepseek.com for OpenAI-compatible requests?
  • Am I using the correct endpoint, such as /chat/completions?
  • Is Content-Type set to application/json?
  • Is the body valid JSON?
  • Are model and messages present?

Authentication

  • Is DEEPSEEK_API_KEY present in the runtime environment?
  • Is the header formatted as Authorization: Bearer <key>?
  • Was the key rotated, revoked, or copied with whitespace?
  • Is the request being made from a secure backend?

Billing

  • Is the account balance available?
  • Is the API key tied to the account you checked?
  • Has usage spiked recently?
  • Are you checking the right environment: dev, staging, or production?

Parameters

  • Is the model ID currently supported?
  • Are optional parameters valid for this endpoint?
  • Did a wrapper add unsupported fields?
  • Are streaming options used only with streaming?
  • Is user_id valid and free of private information?

Rate and server health

  • How many requests are in flight?
  • Are multiple workers sharing one account?
  • Did retries amplify traffic?
  • Is the DeepSeek status page showing an incident?
  • Are errors mostly 429, 500, or 503?

Common DeepSeek Error Code Questions

What are DeepSeek Error Codes?

DeepSeek Error Codes are HTTP-style API errors returned when a DeepSeek API call fails. The official DeepSeek error-code page currently documents 400, 401, 402, 422, 429, 500, and 503.

Which DeepSeek API errors should I retry?

Usually retry 429, 500, and 503, but only with backoff and retry limits. Do not blindly retry 400, 401, 402, or 422; those usually require fixing the request, API key, balance, or parameters.

What does DeepSeek 400 Invalid Format mean?

It means the request body format is invalid. Validate the JSON body, required fields, headers, and SDK serialization before sending the request again.

How do I fix DeepSeek 401 Authentication Fails?

Check that your API key exists, is correct, and is sent as an HTTP Bearer token. DeepSeek’s API reference identifies Bearer Auth as the authentication scheme.

What does DeepSeek 402 Insufficient Balance mean?

It means the account has run out of balance. Check billing and top up if necessary. DeepSeek’s pricing page says API fees are deducted from topped-up or granted balance.

Is DeepSeek 402 the same as a rate limit?

No. 402 is a balance problem. 429 is a request pacing or concurrency problem.

What causes DeepSeek 422 Invalid Parameters?

A 422 means the request contains invalid parameters. Common causes include unsupported model IDs, invalid parameter values, incorrect streaming options, or invalid tool/function settings. The API reference lists current accepted values for key chat completion fields.

What does DeepSeek 429 Rate Limit Reached mean?

It means requests are being sent too quickly. DeepSeek’s current rate-limit page also says exceeding documented account-level concurrency limits returns HTTP 429.

Does DeepSeek publish RPM or TPM limits?

As of July 10, 2026, the public DeepSeek rate-limit page documents concurrency limits for deepseek-v4-pro and deepseek-v4-flash, not a simple public requests-per-minute or tokens-per-minute table on that page.

What is the difference between DeepSeek 500 and 503?

500 means DeepSeek’s server encountered an issue. 503 means the server is overloaded due to high traffic. Both are generally retryable after a short wait, but they should be retried with backoff rather than aggressively.

How do I check whether DeepSeek is down?

Check the official DeepSeek status page and compare API Service status with Web Chat Service status. The API and web chat can behave differently, so do not assume one is down because the other is slow.

Why does DeepSeek web chat feel faster than the API?

DeepSeek’s FAQ says the web service uses streaming output, while the API uses non-streaming output by default when stream=false; non-streaming responses return only after generation is complete.

Why am I receiving empty lines from the DeepSeek API?

DeepSeek says non-streaming requests may return empty lines, and streaming requests may return SSE keep-alive comments while waiting. Your parser should handle those keep-alive signals instead of treating them as malformed JSON.